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660662f8 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * Linux/PA-RISC Project (http://www.parisc-linux.org/) | |
4 | * | |
5 | * Floating-point emulation code | |
6 | * Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org> | |
1da177e4 LT |
7 | */ |
8 | /* | |
9 | * BEGIN_DESC | |
10 | * | |
11 | * File: | |
12 | * @(#) pa/spmath/fmpyfadd.c $Revision: 1.1 $ | |
13 | * | |
14 | * Purpose: | |
15 | * Double Floating-point Multiply Fused Add | |
16 | * Double Floating-point Multiply Negate Fused Add | |
17 | * Single Floating-point Multiply Fused Add | |
18 | * Single Floating-point Multiply Negate Fused Add | |
19 | * | |
20 | * External Interfaces: | |
21 | * dbl_fmpyfadd(src1ptr,src2ptr,src3ptr,status,dstptr) | |
22 | * dbl_fmpynfadd(src1ptr,src2ptr,src3ptr,status,dstptr) | |
23 | * sgl_fmpyfadd(src1ptr,src2ptr,src3ptr,status,dstptr) | |
24 | * sgl_fmpynfadd(src1ptr,src2ptr,src3ptr,status,dstptr) | |
25 | * | |
26 | * Internal Interfaces: | |
27 | * | |
28 | * Theory: | |
29 | * <<please update with a overview of the operation of this file>> | |
30 | * | |
31 | * END_DESC | |
32 | */ | |
33 | ||
34 | ||
35 | #include "float.h" | |
36 | #include "sgl_float.h" | |
37 | #include "dbl_float.h" | |
38 | ||
39 | ||
40 | /* | |
41 | * Double Floating-point Multiply Fused Add | |
42 | */ | |
43 | ||
44 | int | |
45 | dbl_fmpyfadd( | |
46 | dbl_floating_point *src1ptr, | |
47 | dbl_floating_point *src2ptr, | |
48 | dbl_floating_point *src3ptr, | |
49 | unsigned int *status, | |
50 | dbl_floating_point *dstptr) | |
51 | { | |
52 | unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2, opnd3p1, opnd3p2; | |
53 | register unsigned int tmpresp1, tmpresp2, tmpresp3, tmpresp4; | |
54 | unsigned int rightp1, rightp2, rightp3, rightp4; | |
55 | unsigned int resultp1, resultp2 = 0, resultp3 = 0, resultp4 = 0; | |
56 | register int mpy_exponent, add_exponent, count; | |
57 | boolean inexact = FALSE, is_tiny = FALSE; | |
58 | ||
59 | unsigned int signlessleft1, signlessright1, save; | |
60 | register int result_exponent, diff_exponent; | |
61 | int sign_save, jumpsize; | |
62 | ||
63 | Dbl_copyfromptr(src1ptr,opnd1p1,opnd1p2); | |
64 | Dbl_copyfromptr(src2ptr,opnd2p1,opnd2p2); | |
65 | Dbl_copyfromptr(src3ptr,opnd3p1,opnd3p2); | |
66 | ||
67 | /* | |
68 | * set sign bit of result of multiply | |
69 | */ | |
70 | if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1)) | |
71 | Dbl_setnegativezerop1(resultp1); | |
72 | else Dbl_setzerop1(resultp1); | |
73 | ||
74 | /* | |
75 | * Generate multiply exponent | |
76 | */ | |
77 | mpy_exponent = Dbl_exponent(opnd1p1) + Dbl_exponent(opnd2p1) - DBL_BIAS; | |
78 | ||
79 | /* | |
80 | * check first operand for NaN's or infinity | |
81 | */ | |
82 | if (Dbl_isinfinity_exponent(opnd1p1)) { | |
83 | if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { | |
84 | if (Dbl_isnotnan(opnd2p1,opnd2p2) && | |
85 | Dbl_isnotnan(opnd3p1,opnd3p2)) { | |
86 | if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) { | |
87 | /* | |
88 | * invalid since operands are infinity | |
89 | * and zero | |
90 | */ | |
91 | if (Is_invalidtrap_enabled()) | |
92 | return(OPC_2E_INVALIDEXCEPTION); | |
93 | Set_invalidflag(); | |
94 | Dbl_makequietnan(resultp1,resultp2); | |
95 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
96 | return(NOEXCEPTION); | |
97 | } | |
98 | /* | |
99 | * Check third operand for infinity with a | |
100 | * sign opposite of the multiply result | |
101 | */ | |
102 | if (Dbl_isinfinity(opnd3p1,opnd3p2) && | |
103 | (Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) { | |
104 | /* | |
105 | * invalid since attempting a magnitude | |
106 | * subtraction of infinities | |
107 | */ | |
108 | if (Is_invalidtrap_enabled()) | |
109 | return(OPC_2E_INVALIDEXCEPTION); | |
110 | Set_invalidflag(); | |
111 | Dbl_makequietnan(resultp1,resultp2); | |
112 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
113 | return(NOEXCEPTION); | |
114 | } | |
115 | ||
116 | /* | |
117 | * return infinity | |
118 | */ | |
119 | Dbl_setinfinity_exponentmantissa(resultp1,resultp2); | |
120 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
121 | return(NOEXCEPTION); | |
122 | } | |
123 | } | |
124 | else { | |
125 | /* | |
126 | * is NaN; signaling or quiet? | |
127 | */ | |
128 | if (Dbl_isone_signaling(opnd1p1)) { | |
129 | /* trap if INVALIDTRAP enabled */ | |
130 | if (Is_invalidtrap_enabled()) | |
131 | return(OPC_2E_INVALIDEXCEPTION); | |
132 | /* make NaN quiet */ | |
133 | Set_invalidflag(); | |
134 | Dbl_set_quiet(opnd1p1); | |
135 | } | |
136 | /* | |
137 | * is second operand a signaling NaN? | |
138 | */ | |
139 | else if (Dbl_is_signalingnan(opnd2p1)) { | |
140 | /* trap if INVALIDTRAP enabled */ | |
141 | if (Is_invalidtrap_enabled()) | |
142 | return(OPC_2E_INVALIDEXCEPTION); | |
143 | /* make NaN quiet */ | |
144 | Set_invalidflag(); | |
145 | Dbl_set_quiet(opnd2p1); | |
146 | Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); | |
147 | return(NOEXCEPTION); | |
148 | } | |
149 | /* | |
150 | * is third operand a signaling NaN? | |
151 | */ | |
152 | else if (Dbl_is_signalingnan(opnd3p1)) { | |
153 | /* trap if INVALIDTRAP enabled */ | |
154 | if (Is_invalidtrap_enabled()) | |
155 | return(OPC_2E_INVALIDEXCEPTION); | |
156 | /* make NaN quiet */ | |
157 | Set_invalidflag(); | |
158 | Dbl_set_quiet(opnd3p1); | |
159 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
160 | return(NOEXCEPTION); | |
161 | } | |
162 | /* | |
163 | * return quiet NaN | |
164 | */ | |
165 | Dbl_copytoptr(opnd1p1,opnd1p2,dstptr); | |
166 | return(NOEXCEPTION); | |
167 | } | |
168 | } | |
169 | ||
170 | /* | |
171 | * check second operand for NaN's or infinity | |
172 | */ | |
173 | if (Dbl_isinfinity_exponent(opnd2p1)) { | |
174 | if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { | |
175 | if (Dbl_isnotnan(opnd3p1,opnd3p2)) { | |
176 | if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) { | |
177 | /* | |
178 | * invalid since multiply operands are | |
179 | * zero & infinity | |
180 | */ | |
181 | if (Is_invalidtrap_enabled()) | |
182 | return(OPC_2E_INVALIDEXCEPTION); | |
183 | Set_invalidflag(); | |
184 | Dbl_makequietnan(opnd2p1,opnd2p2); | |
185 | Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); | |
186 | return(NOEXCEPTION); | |
187 | } | |
188 | ||
189 | /* | |
190 | * Check third operand for infinity with a | |
191 | * sign opposite of the multiply result | |
192 | */ | |
193 | if (Dbl_isinfinity(opnd3p1,opnd3p2) && | |
194 | (Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) { | |
195 | /* | |
196 | * invalid since attempting a magnitude | |
197 | * subtraction of infinities | |
198 | */ | |
199 | if (Is_invalidtrap_enabled()) | |
200 | return(OPC_2E_INVALIDEXCEPTION); | |
201 | Set_invalidflag(); | |
202 | Dbl_makequietnan(resultp1,resultp2); | |
203 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
204 | return(NOEXCEPTION); | |
205 | } | |
206 | ||
207 | /* | |
208 | * return infinity | |
209 | */ | |
210 | Dbl_setinfinity_exponentmantissa(resultp1,resultp2); | |
211 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
212 | return(NOEXCEPTION); | |
213 | } | |
214 | } | |
215 | else { | |
216 | /* | |
217 | * is NaN; signaling or quiet? | |
218 | */ | |
219 | if (Dbl_isone_signaling(opnd2p1)) { | |
220 | /* trap if INVALIDTRAP enabled */ | |
221 | if (Is_invalidtrap_enabled()) | |
222 | return(OPC_2E_INVALIDEXCEPTION); | |
223 | /* make NaN quiet */ | |
224 | Set_invalidflag(); | |
225 | Dbl_set_quiet(opnd2p1); | |
226 | } | |
227 | /* | |
228 | * is third operand a signaling NaN? | |
229 | */ | |
230 | else if (Dbl_is_signalingnan(opnd3p1)) { | |
231 | /* trap if INVALIDTRAP enabled */ | |
232 | if (Is_invalidtrap_enabled()) | |
233 | return(OPC_2E_INVALIDEXCEPTION); | |
234 | /* make NaN quiet */ | |
235 | Set_invalidflag(); | |
236 | Dbl_set_quiet(opnd3p1); | |
237 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
238 | return(NOEXCEPTION); | |
239 | } | |
240 | /* | |
241 | * return quiet NaN | |
242 | */ | |
243 | Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); | |
244 | return(NOEXCEPTION); | |
245 | } | |
246 | } | |
247 | ||
248 | /* | |
249 | * check third operand for NaN's or infinity | |
250 | */ | |
251 | if (Dbl_isinfinity_exponent(opnd3p1)) { | |
252 | if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) { | |
253 | /* return infinity */ | |
254 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
255 | return(NOEXCEPTION); | |
256 | } else { | |
257 | /* | |
258 | * is NaN; signaling or quiet? | |
259 | */ | |
260 | if (Dbl_isone_signaling(opnd3p1)) { | |
261 | /* trap if INVALIDTRAP enabled */ | |
262 | if (Is_invalidtrap_enabled()) | |
263 | return(OPC_2E_INVALIDEXCEPTION); | |
264 | /* make NaN quiet */ | |
265 | Set_invalidflag(); | |
266 | Dbl_set_quiet(opnd3p1); | |
267 | } | |
268 | /* | |
269 | * return quiet NaN | |
270 | */ | |
271 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
272 | return(NOEXCEPTION); | |
273 | } | |
274 | } | |
275 | ||
276 | /* | |
277 | * Generate multiply mantissa | |
278 | */ | |
279 | if (Dbl_isnotzero_exponent(opnd1p1)) { | |
280 | /* set hidden bit */ | |
281 | Dbl_clear_signexponent_set_hidden(opnd1p1); | |
282 | } | |
283 | else { | |
284 | /* check for zero */ | |
285 | if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { | |
286 | /* | |
287 | * Perform the add opnd3 with zero here. | |
288 | */ | |
289 | if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) { | |
290 | if (Is_rounding_mode(ROUNDMINUS)) { | |
291 | Dbl_or_signs(opnd3p1,resultp1); | |
292 | } else { | |
293 | Dbl_and_signs(opnd3p1,resultp1); | |
294 | } | |
295 | } | |
296 | /* | |
297 | * Now let's check for trapped underflow case. | |
298 | */ | |
299 | else if (Dbl_iszero_exponent(opnd3p1) && | |
300 | Is_underflowtrap_enabled()) { | |
301 | /* need to normalize results mantissa */ | |
302 | sign_save = Dbl_signextendedsign(opnd3p1); | |
303 | result_exponent = 0; | |
304 | Dbl_leftshiftby1(opnd3p1,opnd3p2); | |
305 | Dbl_normalize(opnd3p1,opnd3p2,result_exponent); | |
306 | Dbl_set_sign(opnd3p1,/*using*/sign_save); | |
307 | Dbl_setwrapped_exponent(opnd3p1,result_exponent, | |
308 | unfl); | |
309 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
310 | /* inexact = FALSE */ | |
311 | return(OPC_2E_UNDERFLOWEXCEPTION); | |
312 | } | |
313 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
314 | return(NOEXCEPTION); | |
315 | } | |
316 | /* is denormalized, adjust exponent */ | |
317 | Dbl_clear_signexponent(opnd1p1); | |
318 | Dbl_leftshiftby1(opnd1p1,opnd1p2); | |
319 | Dbl_normalize(opnd1p1,opnd1p2,mpy_exponent); | |
320 | } | |
321 | /* opnd2 needs to have hidden bit set with msb in hidden bit */ | |
322 | if (Dbl_isnotzero_exponent(opnd2p1)) { | |
323 | Dbl_clear_signexponent_set_hidden(opnd2p1); | |
324 | } | |
325 | else { | |
326 | /* check for zero */ | |
327 | if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { | |
328 | /* | |
329 | * Perform the add opnd3 with zero here. | |
330 | */ | |
331 | if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) { | |
332 | if (Is_rounding_mode(ROUNDMINUS)) { | |
333 | Dbl_or_signs(opnd3p1,resultp1); | |
334 | } else { | |
335 | Dbl_and_signs(opnd3p1,resultp1); | |
336 | } | |
337 | } | |
338 | /* | |
339 | * Now let's check for trapped underflow case. | |
340 | */ | |
341 | else if (Dbl_iszero_exponent(opnd3p1) && | |
342 | Is_underflowtrap_enabled()) { | |
343 | /* need to normalize results mantissa */ | |
344 | sign_save = Dbl_signextendedsign(opnd3p1); | |
345 | result_exponent = 0; | |
346 | Dbl_leftshiftby1(opnd3p1,opnd3p2); | |
347 | Dbl_normalize(opnd3p1,opnd3p2,result_exponent); | |
348 | Dbl_set_sign(opnd3p1,/*using*/sign_save); | |
349 | Dbl_setwrapped_exponent(opnd3p1,result_exponent, | |
350 | unfl); | |
351 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
352 | /* inexact = FALSE */ | |
353 | return(OPC_2E_UNDERFLOWEXCEPTION); | |
354 | } | |
355 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
356 | return(NOEXCEPTION); | |
357 | } | |
358 | /* is denormalized; want to normalize */ | |
359 | Dbl_clear_signexponent(opnd2p1); | |
360 | Dbl_leftshiftby1(opnd2p1,opnd2p2); | |
361 | Dbl_normalize(opnd2p1,opnd2p2,mpy_exponent); | |
362 | } | |
363 | ||
364 | /* Multiply the first two source mantissas together */ | |
365 | ||
366 | /* | |
367 | * The intermediate result will be kept in tmpres, | |
368 | * which needs enough room for 106 bits of mantissa, | |
369 | * so lets call it a Double extended. | |
370 | */ | |
371 | Dblext_setzero(tmpresp1,tmpresp2,tmpresp3,tmpresp4); | |
372 | ||
373 | /* | |
374 | * Four bits at a time are inspected in each loop, and a | |
375 | * simple shift and add multiply algorithm is used. | |
376 | */ | |
377 | for (count = DBL_P-1; count >= 0; count -= 4) { | |
378 | Dblext_rightshiftby4(tmpresp1,tmpresp2,tmpresp3,tmpresp4); | |
379 | if (Dbit28p2(opnd1p2)) { | |
380 | /* Fourword_add should be an ADD followed by 3 ADDC's */ | |
381 | Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, | |
382 | opnd2p1<<3 | opnd2p2>>29, opnd2p2<<3, 0, 0); | |
383 | } | |
384 | if (Dbit29p2(opnd1p2)) { | |
385 | Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, | |
386 | opnd2p1<<2 | opnd2p2>>30, opnd2p2<<2, 0, 0); | |
387 | } | |
388 | if (Dbit30p2(opnd1p2)) { | |
389 | Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, | |
390 | opnd2p1<<1 | opnd2p2>>31, opnd2p2<<1, 0, 0); | |
391 | } | |
392 | if (Dbit31p2(opnd1p2)) { | |
393 | Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, | |
394 | opnd2p1, opnd2p2, 0, 0); | |
395 | } | |
396 | Dbl_rightshiftby4(opnd1p1,opnd1p2); | |
397 | } | |
398 | if (Is_dexthiddenoverflow(tmpresp1)) { | |
399 | /* result mantissa >= 2 (mantissa overflow) */ | |
400 | mpy_exponent++; | |
401 | Dblext_rightshiftby1(tmpresp1,tmpresp2,tmpresp3,tmpresp4); | |
402 | } | |
403 | ||
404 | /* | |
405 | * Restore the sign of the mpy result which was saved in resultp1. | |
406 | * The exponent will continue to be kept in mpy_exponent. | |
407 | */ | |
408 | Dblext_set_sign(tmpresp1,Dbl_sign(resultp1)); | |
409 | ||
410 | /* | |
411 | * No rounding is required, since the result of the multiply | |
412 | * is exact in the extended format. | |
413 | */ | |
414 | ||
415 | /* | |
416 | * Now we are ready to perform the add portion of the operation. | |
417 | * | |
418 | * The exponents need to be kept as integers for now, since the | |
419 | * multiply result might not fit into the exponent field. We | |
420 | * can't overflow or underflow because of this yet, since the | |
421 | * add could bring the final result back into range. | |
422 | */ | |
423 | add_exponent = Dbl_exponent(opnd3p1); | |
424 | ||
425 | /* | |
426 | * Check for denormalized or zero add operand. | |
427 | */ | |
428 | if (add_exponent == 0) { | |
429 | /* check for zero */ | |
430 | if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) { | |
431 | /* right is zero */ | |
432 | /* Left can't be zero and must be result. | |
433 | * | |
434 | * The final result is now in tmpres and mpy_exponent, | |
435 | * and needs to be rounded and squeezed back into | |
436 | * double precision format from double extended. | |
437 | */ | |
438 | result_exponent = mpy_exponent; | |
439 | Dblext_copy(tmpresp1,tmpresp2,tmpresp3,tmpresp4, | |
440 | resultp1,resultp2,resultp3,resultp4); | |
441 | sign_save = Dbl_signextendedsign(resultp1);/*save sign*/ | |
442 | goto round; | |
443 | } | |
444 | ||
445 | /* | |
446 | * Neither are zeroes. | |
447 | * Adjust exponent and normalize add operand. | |
448 | */ | |
449 | sign_save = Dbl_signextendedsign(opnd3p1); /* save sign */ | |
450 | Dbl_clear_signexponent(opnd3p1); | |
451 | Dbl_leftshiftby1(opnd3p1,opnd3p2); | |
452 | Dbl_normalize(opnd3p1,opnd3p2,add_exponent); | |
453 | Dbl_set_sign(opnd3p1,sign_save); /* restore sign */ | |
454 | } else { | |
455 | Dbl_clear_exponent_set_hidden(opnd3p1); | |
456 | } | |
457 | /* | |
458 | * Copy opnd3 to the double extended variable called right. | |
459 | */ | |
460 | Dbl_copyto_dblext(opnd3p1,opnd3p2,rightp1,rightp2,rightp3,rightp4); | |
461 | ||
462 | /* | |
463 | * A zero "save" helps discover equal operands (for later), | |
464 | * and is used in swapping operands (if needed). | |
465 | */ | |
466 | Dblext_xortointp1(tmpresp1,rightp1,/*to*/save); | |
467 | ||
468 | /* | |
469 | * Compare magnitude of operands. | |
470 | */ | |
471 | Dblext_copytoint_exponentmantissap1(tmpresp1,signlessleft1); | |
472 | Dblext_copytoint_exponentmantissap1(rightp1,signlessright1); | |
473 | if (mpy_exponent < add_exponent || mpy_exponent == add_exponent && | |
474 | Dblext_ismagnitudeless(tmpresp2,rightp2,signlessleft1,signlessright1)){ | |
475 | /* | |
476 | * Set the left operand to the larger one by XOR swap. | |
477 | * First finish the first word "save". | |
478 | */ | |
479 | Dblext_xorfromintp1(save,rightp1,/*to*/rightp1); | |
480 | Dblext_xorfromintp1(save,tmpresp1,/*to*/tmpresp1); | |
481 | Dblext_swap_lower(tmpresp2,tmpresp3,tmpresp4, | |
482 | rightp2,rightp3,rightp4); | |
483 | /* also setup exponents used in rest of routine */ | |
484 | diff_exponent = add_exponent - mpy_exponent; | |
485 | result_exponent = add_exponent; | |
486 | } else { | |
487 | /* also setup exponents used in rest of routine */ | |
488 | diff_exponent = mpy_exponent - add_exponent; | |
489 | result_exponent = mpy_exponent; | |
490 | } | |
491 | /* Invariant: left is not smaller than right. */ | |
492 | ||
493 | /* | |
494 | * Special case alignment of operands that would force alignment | |
495 | * beyond the extent of the extension. A further optimization | |
496 | * could special case this but only reduces the path length for | |
497 | * this infrequent case. | |
498 | */ | |
499 | if (diff_exponent > DBLEXT_THRESHOLD) { | |
500 | diff_exponent = DBLEXT_THRESHOLD; | |
501 | } | |
502 | ||
503 | /* Align right operand by shifting it to the right */ | |
504 | Dblext_clear_sign(rightp1); | |
505 | Dblext_right_align(rightp1,rightp2,rightp3,rightp4, | |
506 | /*shifted by*/diff_exponent); | |
507 | ||
508 | /* Treat sum and difference of the operands separately. */ | |
509 | if ((int)save < 0) { | |
510 | /* | |
511 | * Difference of the two operands. Overflow can occur if the | |
512 | * multiply overflowed. A borrow can occur out of the hidden | |
513 | * bit and force a post normalization phase. | |
514 | */ | |
515 | Dblext_subtract(tmpresp1,tmpresp2,tmpresp3,tmpresp4, | |
516 | rightp1,rightp2,rightp3,rightp4, | |
517 | resultp1,resultp2,resultp3,resultp4); | |
518 | sign_save = Dbl_signextendedsign(resultp1); | |
519 | if (Dbl_iszero_hidden(resultp1)) { | |
520 | /* Handle normalization */ | |
25985edc | 521 | /* A straightforward algorithm would now shift the |
1da177e4 LT |
522 | * result and extension left until the hidden bit |
523 | * becomes one. Not all of the extension bits need | |
524 | * participate in the shift. Only the two most | |
525 | * significant bits (round and guard) are needed. | |
526 | * If only a single shift is needed then the guard | |
527 | * bit becomes a significant low order bit and the | |
528 | * extension must participate in the rounding. | |
529 | * If more than a single shift is needed, then all | |
530 | * bits to the right of the guard bit are zeros, | |
531 | * and the guard bit may or may not be zero. */ | |
532 | Dblext_leftshiftby1(resultp1,resultp2,resultp3, | |
533 | resultp4); | |
534 | ||
535 | /* Need to check for a zero result. The sign and | |
536 | * exponent fields have already been zeroed. The more | |
537 | * efficient test of the full object can be used. | |
538 | */ | |
539 | if(Dblext_iszero(resultp1,resultp2,resultp3,resultp4)){ | |
540 | /* Must have been "x-x" or "x+(-x)". */ | |
541 | if (Is_rounding_mode(ROUNDMINUS)) | |
542 | Dbl_setone_sign(resultp1); | |
543 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
544 | return(NOEXCEPTION); | |
545 | } | |
546 | result_exponent--; | |
547 | ||
548 | /* Look to see if normalization is finished. */ | |
549 | if (Dbl_isone_hidden(resultp1)) { | |
550 | /* No further normalization is needed */ | |
551 | goto round; | |
552 | } | |
553 | ||
554 | /* Discover first one bit to determine shift amount. | |
555 | * Use a modified binary search. We have already | |
556 | * shifted the result one position right and still | |
557 | * not found a one so the remainder of the extension | |
558 | * must be zero and simplifies rounding. */ | |
559 | /* Scan bytes */ | |
560 | while (Dbl_iszero_hiddenhigh7mantissa(resultp1)) { | |
561 | Dblext_leftshiftby8(resultp1,resultp2,resultp3,resultp4); | |
562 | result_exponent -= 8; | |
563 | } | |
564 | /* Now narrow it down to the nibble */ | |
565 | if (Dbl_iszero_hiddenhigh3mantissa(resultp1)) { | |
566 | /* The lower nibble contains the | |
567 | * normalizing one */ | |
568 | Dblext_leftshiftby4(resultp1,resultp2,resultp3,resultp4); | |
569 | result_exponent -= 4; | |
570 | } | |
571 | /* Select case where first bit is set (already | |
572 | * normalized) otherwise select the proper shift. */ | |
573 | jumpsize = Dbl_hiddenhigh3mantissa(resultp1); | |
574 | if (jumpsize <= 7) switch(jumpsize) { | |
575 | case 1: | |
576 | Dblext_leftshiftby3(resultp1,resultp2,resultp3, | |
577 | resultp4); | |
578 | result_exponent -= 3; | |
579 | break; | |
580 | case 2: | |
581 | case 3: | |
582 | Dblext_leftshiftby2(resultp1,resultp2,resultp3, | |
583 | resultp4); | |
584 | result_exponent -= 2; | |
585 | break; | |
586 | case 4: | |
587 | case 5: | |
588 | case 6: | |
589 | case 7: | |
590 | Dblext_leftshiftby1(resultp1,resultp2,resultp3, | |
591 | resultp4); | |
592 | result_exponent -= 1; | |
593 | break; | |
594 | } | |
595 | } /* end if (hidden...)... */ | |
596 | /* Fall through and round */ | |
597 | } /* end if (save < 0)... */ | |
598 | else { | |
599 | /* Add magnitudes */ | |
600 | Dblext_addition(tmpresp1,tmpresp2,tmpresp3,tmpresp4, | |
601 | rightp1,rightp2,rightp3,rightp4, | |
602 | /*to*/resultp1,resultp2,resultp3,resultp4); | |
603 | sign_save = Dbl_signextendedsign(resultp1); | |
604 | if (Dbl_isone_hiddenoverflow(resultp1)) { | |
605 | /* Prenormalization required. */ | |
606 | Dblext_arithrightshiftby1(resultp1,resultp2,resultp3, | |
607 | resultp4); | |
608 | result_exponent++; | |
609 | } /* end if hiddenoverflow... */ | |
610 | } /* end else ...add magnitudes... */ | |
611 | ||
612 | /* Round the result. If the extension and lower two words are | |
613 | * all zeros, then the result is exact. Otherwise round in the | |
614 | * correct direction. Underflow is possible. If a postnormalization | |
615 | * is necessary, then the mantissa is all zeros so no shift is needed. | |
616 | */ | |
617 | round: | |
618 | if (result_exponent <= 0 && !Is_underflowtrap_enabled()) { | |
619 | Dblext_denormalize(resultp1,resultp2,resultp3,resultp4, | |
620 | result_exponent,is_tiny); | |
621 | } | |
622 | Dbl_set_sign(resultp1,/*using*/sign_save); | |
623 | if (Dblext_isnotzero_mantissap3(resultp3) || | |
624 | Dblext_isnotzero_mantissap4(resultp4)) { | |
625 | inexact = TRUE; | |
626 | switch(Rounding_mode()) { | |
627 | case ROUNDNEAREST: /* The default. */ | |
628 | if (Dblext_isone_highp3(resultp3)) { | |
629 | /* at least 1/2 ulp */ | |
630 | if (Dblext_isnotzero_low31p3(resultp3) || | |
631 | Dblext_isnotzero_mantissap4(resultp4) || | |
632 | Dblext_isone_lowp2(resultp2)) { | |
633 | /* either exactly half way and odd or | |
634 | * more than 1/2ulp */ | |
635 | Dbl_increment(resultp1,resultp2); | |
636 | } | |
637 | } | |
638 | break; | |
639 | ||
640 | case ROUNDPLUS: | |
641 | if (Dbl_iszero_sign(resultp1)) { | |
642 | /* Round up positive results */ | |
643 | Dbl_increment(resultp1,resultp2); | |
644 | } | |
645 | break; | |
646 | ||
647 | case ROUNDMINUS: | |
648 | if (Dbl_isone_sign(resultp1)) { | |
649 | /* Round down negative results */ | |
650 | Dbl_increment(resultp1,resultp2); | |
651 | } | |
652 | ||
653 | case ROUNDZERO:; | |
654 | /* truncate is simple */ | |
655 | } /* end switch... */ | |
656 | if (Dbl_isone_hiddenoverflow(resultp1)) result_exponent++; | |
657 | } | |
658 | if (result_exponent >= DBL_INFINITY_EXPONENT) { | |
659 | /* trap if OVERFLOWTRAP enabled */ | |
660 | if (Is_overflowtrap_enabled()) { | |
661 | /* | |
662 | * Adjust bias of result | |
663 | */ | |
664 | Dbl_setwrapped_exponent(resultp1,result_exponent,ovfl); | |
665 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
666 | if (inexact) | |
667 | if (Is_inexacttrap_enabled()) | |
668 | return (OPC_2E_OVERFLOWEXCEPTION | | |
669 | OPC_2E_INEXACTEXCEPTION); | |
670 | else Set_inexactflag(); | |
671 | return (OPC_2E_OVERFLOWEXCEPTION); | |
672 | } | |
673 | inexact = TRUE; | |
674 | Set_overflowflag(); | |
675 | /* set result to infinity or largest number */ | |
676 | Dbl_setoverflow(resultp1,resultp2); | |
677 | ||
678 | } else if (result_exponent <= 0) { /* underflow case */ | |
679 | if (Is_underflowtrap_enabled()) { | |
680 | /* | |
681 | * Adjust bias of result | |
682 | */ | |
683 | Dbl_setwrapped_exponent(resultp1,result_exponent,unfl); | |
684 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
685 | if (inexact) | |
686 | if (Is_inexacttrap_enabled()) | |
687 | return (OPC_2E_UNDERFLOWEXCEPTION | | |
688 | OPC_2E_INEXACTEXCEPTION); | |
689 | else Set_inexactflag(); | |
690 | return(OPC_2E_UNDERFLOWEXCEPTION); | |
691 | } | |
692 | else if (inexact && is_tiny) Set_underflowflag(); | |
693 | } | |
694 | else Dbl_set_exponent(resultp1,result_exponent); | |
695 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
696 | if (inexact) | |
697 | if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION); | |
698 | else Set_inexactflag(); | |
699 | return(NOEXCEPTION); | |
700 | } | |
701 | ||
702 | /* | |
703 | * Double Floating-point Multiply Negate Fused Add | |
704 | */ | |
705 | ||
706 | dbl_fmpynfadd(src1ptr,src2ptr,src3ptr,status,dstptr) | |
707 | ||
708 | dbl_floating_point *src1ptr, *src2ptr, *src3ptr, *dstptr; | |
709 | unsigned int *status; | |
710 | { | |
711 | unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2, opnd3p1, opnd3p2; | |
712 | register unsigned int tmpresp1, tmpresp2, tmpresp3, tmpresp4; | |
713 | unsigned int rightp1, rightp2, rightp3, rightp4; | |
714 | unsigned int resultp1, resultp2 = 0, resultp3 = 0, resultp4 = 0; | |
715 | register int mpy_exponent, add_exponent, count; | |
716 | boolean inexact = FALSE, is_tiny = FALSE; | |
717 | ||
718 | unsigned int signlessleft1, signlessright1, save; | |
719 | register int result_exponent, diff_exponent; | |
720 | int sign_save, jumpsize; | |
721 | ||
722 | Dbl_copyfromptr(src1ptr,opnd1p1,opnd1p2); | |
723 | Dbl_copyfromptr(src2ptr,opnd2p1,opnd2p2); | |
724 | Dbl_copyfromptr(src3ptr,opnd3p1,opnd3p2); | |
725 | ||
726 | /* | |
727 | * set sign bit of result of multiply | |
728 | */ | |
729 | if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1)) | |
730 | Dbl_setzerop1(resultp1); | |
731 | else | |
732 | Dbl_setnegativezerop1(resultp1); | |
733 | ||
734 | /* | |
735 | * Generate multiply exponent | |
736 | */ | |
737 | mpy_exponent = Dbl_exponent(opnd1p1) + Dbl_exponent(opnd2p1) - DBL_BIAS; | |
738 | ||
739 | /* | |
740 | * check first operand for NaN's or infinity | |
741 | */ | |
742 | if (Dbl_isinfinity_exponent(opnd1p1)) { | |
743 | if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { | |
744 | if (Dbl_isnotnan(opnd2p1,opnd2p2) && | |
745 | Dbl_isnotnan(opnd3p1,opnd3p2)) { | |
746 | if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) { | |
747 | /* | |
748 | * invalid since operands are infinity | |
749 | * and zero | |
750 | */ | |
751 | if (Is_invalidtrap_enabled()) | |
752 | return(OPC_2E_INVALIDEXCEPTION); | |
753 | Set_invalidflag(); | |
754 | Dbl_makequietnan(resultp1,resultp2); | |
755 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
756 | return(NOEXCEPTION); | |
757 | } | |
758 | /* | |
759 | * Check third operand for infinity with a | |
760 | * sign opposite of the multiply result | |
761 | */ | |
762 | if (Dbl_isinfinity(opnd3p1,opnd3p2) && | |
763 | (Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) { | |
764 | /* | |
765 | * invalid since attempting a magnitude | |
766 | * subtraction of infinities | |
767 | */ | |
768 | if (Is_invalidtrap_enabled()) | |
769 | return(OPC_2E_INVALIDEXCEPTION); | |
770 | Set_invalidflag(); | |
771 | Dbl_makequietnan(resultp1,resultp2); | |
772 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
773 | return(NOEXCEPTION); | |
774 | } | |
775 | ||
776 | /* | |
777 | * return infinity | |
778 | */ | |
779 | Dbl_setinfinity_exponentmantissa(resultp1,resultp2); | |
780 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
781 | return(NOEXCEPTION); | |
782 | } | |
783 | } | |
784 | else { | |
785 | /* | |
786 | * is NaN; signaling or quiet? | |
787 | */ | |
788 | if (Dbl_isone_signaling(opnd1p1)) { | |
789 | /* trap if INVALIDTRAP enabled */ | |
790 | if (Is_invalidtrap_enabled()) | |
791 | return(OPC_2E_INVALIDEXCEPTION); | |
792 | /* make NaN quiet */ | |
793 | Set_invalidflag(); | |
794 | Dbl_set_quiet(opnd1p1); | |
795 | } | |
796 | /* | |
797 | * is second operand a signaling NaN? | |
798 | */ | |
799 | else if (Dbl_is_signalingnan(opnd2p1)) { | |
800 | /* trap if INVALIDTRAP enabled */ | |
801 | if (Is_invalidtrap_enabled()) | |
802 | return(OPC_2E_INVALIDEXCEPTION); | |
803 | /* make NaN quiet */ | |
804 | Set_invalidflag(); | |
805 | Dbl_set_quiet(opnd2p1); | |
806 | Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); | |
807 | return(NOEXCEPTION); | |
808 | } | |
809 | /* | |
810 | * is third operand a signaling NaN? | |
811 | */ | |
812 | else if (Dbl_is_signalingnan(opnd3p1)) { | |
813 | /* trap if INVALIDTRAP enabled */ | |
814 | if (Is_invalidtrap_enabled()) | |
815 | return(OPC_2E_INVALIDEXCEPTION); | |
816 | /* make NaN quiet */ | |
817 | Set_invalidflag(); | |
818 | Dbl_set_quiet(opnd3p1); | |
819 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
820 | return(NOEXCEPTION); | |
821 | } | |
822 | /* | |
823 | * return quiet NaN | |
824 | */ | |
825 | Dbl_copytoptr(opnd1p1,opnd1p2,dstptr); | |
826 | return(NOEXCEPTION); | |
827 | } | |
828 | } | |
829 | ||
830 | /* | |
831 | * check second operand for NaN's or infinity | |
832 | */ | |
833 | if (Dbl_isinfinity_exponent(opnd2p1)) { | |
834 | if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { | |
835 | if (Dbl_isnotnan(opnd3p1,opnd3p2)) { | |
836 | if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) { | |
837 | /* | |
838 | * invalid since multiply operands are | |
839 | * zero & infinity | |
840 | */ | |
841 | if (Is_invalidtrap_enabled()) | |
842 | return(OPC_2E_INVALIDEXCEPTION); | |
843 | Set_invalidflag(); | |
844 | Dbl_makequietnan(opnd2p1,opnd2p2); | |
845 | Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); | |
846 | return(NOEXCEPTION); | |
847 | } | |
848 | ||
849 | /* | |
850 | * Check third operand for infinity with a | |
851 | * sign opposite of the multiply result | |
852 | */ | |
853 | if (Dbl_isinfinity(opnd3p1,opnd3p2) && | |
854 | (Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) { | |
855 | /* | |
856 | * invalid since attempting a magnitude | |
857 | * subtraction of infinities | |
858 | */ | |
859 | if (Is_invalidtrap_enabled()) | |
860 | return(OPC_2E_INVALIDEXCEPTION); | |
861 | Set_invalidflag(); | |
862 | Dbl_makequietnan(resultp1,resultp2); | |
863 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
864 | return(NOEXCEPTION); | |
865 | } | |
866 | ||
867 | /* | |
868 | * return infinity | |
869 | */ | |
870 | Dbl_setinfinity_exponentmantissa(resultp1,resultp2); | |
871 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
872 | return(NOEXCEPTION); | |
873 | } | |
874 | } | |
875 | else { | |
876 | /* | |
877 | * is NaN; signaling or quiet? | |
878 | */ | |
879 | if (Dbl_isone_signaling(opnd2p1)) { | |
880 | /* trap if INVALIDTRAP enabled */ | |
881 | if (Is_invalidtrap_enabled()) | |
882 | return(OPC_2E_INVALIDEXCEPTION); | |
883 | /* make NaN quiet */ | |
884 | Set_invalidflag(); | |
885 | Dbl_set_quiet(opnd2p1); | |
886 | } | |
887 | /* | |
888 | * is third operand a signaling NaN? | |
889 | */ | |
890 | else if (Dbl_is_signalingnan(opnd3p1)) { | |
891 | /* trap if INVALIDTRAP enabled */ | |
892 | if (Is_invalidtrap_enabled()) | |
893 | return(OPC_2E_INVALIDEXCEPTION); | |
894 | /* make NaN quiet */ | |
895 | Set_invalidflag(); | |
896 | Dbl_set_quiet(opnd3p1); | |
897 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
898 | return(NOEXCEPTION); | |
899 | } | |
900 | /* | |
901 | * return quiet NaN | |
902 | */ | |
903 | Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); | |
904 | return(NOEXCEPTION); | |
905 | } | |
906 | } | |
907 | ||
908 | /* | |
909 | * check third operand for NaN's or infinity | |
910 | */ | |
911 | if (Dbl_isinfinity_exponent(opnd3p1)) { | |
912 | if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) { | |
913 | /* return infinity */ | |
914 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
915 | return(NOEXCEPTION); | |
916 | } else { | |
917 | /* | |
918 | * is NaN; signaling or quiet? | |
919 | */ | |
920 | if (Dbl_isone_signaling(opnd3p1)) { | |
921 | /* trap if INVALIDTRAP enabled */ | |
922 | if (Is_invalidtrap_enabled()) | |
923 | return(OPC_2E_INVALIDEXCEPTION); | |
924 | /* make NaN quiet */ | |
925 | Set_invalidflag(); | |
926 | Dbl_set_quiet(opnd3p1); | |
927 | } | |
928 | /* | |
929 | * return quiet NaN | |
930 | */ | |
931 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
932 | return(NOEXCEPTION); | |
933 | } | |
934 | } | |
935 | ||
936 | /* | |
937 | * Generate multiply mantissa | |
938 | */ | |
939 | if (Dbl_isnotzero_exponent(opnd1p1)) { | |
940 | /* set hidden bit */ | |
941 | Dbl_clear_signexponent_set_hidden(opnd1p1); | |
942 | } | |
943 | else { | |
944 | /* check for zero */ | |
945 | if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { | |
946 | /* | |
947 | * Perform the add opnd3 with zero here. | |
948 | */ | |
949 | if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) { | |
950 | if (Is_rounding_mode(ROUNDMINUS)) { | |
951 | Dbl_or_signs(opnd3p1,resultp1); | |
952 | } else { | |
953 | Dbl_and_signs(opnd3p1,resultp1); | |
954 | } | |
955 | } | |
956 | /* | |
957 | * Now let's check for trapped underflow case. | |
958 | */ | |
959 | else if (Dbl_iszero_exponent(opnd3p1) && | |
960 | Is_underflowtrap_enabled()) { | |
961 | /* need to normalize results mantissa */ | |
962 | sign_save = Dbl_signextendedsign(opnd3p1); | |
963 | result_exponent = 0; | |
964 | Dbl_leftshiftby1(opnd3p1,opnd3p2); | |
965 | Dbl_normalize(opnd3p1,opnd3p2,result_exponent); | |
966 | Dbl_set_sign(opnd3p1,/*using*/sign_save); | |
967 | Dbl_setwrapped_exponent(opnd3p1,result_exponent, | |
968 | unfl); | |
969 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
970 | /* inexact = FALSE */ | |
971 | return(OPC_2E_UNDERFLOWEXCEPTION); | |
972 | } | |
973 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
974 | return(NOEXCEPTION); | |
975 | } | |
976 | /* is denormalized, adjust exponent */ | |
977 | Dbl_clear_signexponent(opnd1p1); | |
978 | Dbl_leftshiftby1(opnd1p1,opnd1p2); | |
979 | Dbl_normalize(opnd1p1,opnd1p2,mpy_exponent); | |
980 | } | |
981 | /* opnd2 needs to have hidden bit set with msb in hidden bit */ | |
982 | if (Dbl_isnotzero_exponent(opnd2p1)) { | |
983 | Dbl_clear_signexponent_set_hidden(opnd2p1); | |
984 | } | |
985 | else { | |
986 | /* check for zero */ | |
987 | if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { | |
988 | /* | |
989 | * Perform the add opnd3 with zero here. | |
990 | */ | |
991 | if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) { | |
992 | if (Is_rounding_mode(ROUNDMINUS)) { | |
993 | Dbl_or_signs(opnd3p1,resultp1); | |
994 | } else { | |
995 | Dbl_and_signs(opnd3p1,resultp1); | |
996 | } | |
997 | } | |
998 | /* | |
999 | * Now let's check for trapped underflow case. | |
1000 | */ | |
1001 | else if (Dbl_iszero_exponent(opnd3p1) && | |
1002 | Is_underflowtrap_enabled()) { | |
1003 | /* need to normalize results mantissa */ | |
1004 | sign_save = Dbl_signextendedsign(opnd3p1); | |
1005 | result_exponent = 0; | |
1006 | Dbl_leftshiftby1(opnd3p1,opnd3p2); | |
1007 | Dbl_normalize(opnd3p1,opnd3p2,result_exponent); | |
1008 | Dbl_set_sign(opnd3p1,/*using*/sign_save); | |
1009 | Dbl_setwrapped_exponent(opnd3p1,result_exponent, | |
1010 | unfl); | |
1011 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
1012 | /* inexact = FALSE */ | |
1013 | return(OPC_2E_UNDERFLOWEXCEPTION); | |
1014 | } | |
1015 | Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); | |
1016 | return(NOEXCEPTION); | |
1017 | } | |
1018 | /* is denormalized; want to normalize */ | |
1019 | Dbl_clear_signexponent(opnd2p1); | |
1020 | Dbl_leftshiftby1(opnd2p1,opnd2p2); | |
1021 | Dbl_normalize(opnd2p1,opnd2p2,mpy_exponent); | |
1022 | } | |
1023 | ||
1024 | /* Multiply the first two source mantissas together */ | |
1025 | ||
1026 | /* | |
1027 | * The intermediate result will be kept in tmpres, | |
1028 | * which needs enough room for 106 bits of mantissa, | |
1029 | * so lets call it a Double extended. | |
1030 | */ | |
1031 | Dblext_setzero(tmpresp1,tmpresp2,tmpresp3,tmpresp4); | |
1032 | ||
1033 | /* | |
1034 | * Four bits at a time are inspected in each loop, and a | |
1035 | * simple shift and add multiply algorithm is used. | |
1036 | */ | |
1037 | for (count = DBL_P-1; count >= 0; count -= 4) { | |
1038 | Dblext_rightshiftby4(tmpresp1,tmpresp2,tmpresp3,tmpresp4); | |
1039 | if (Dbit28p2(opnd1p2)) { | |
1040 | /* Fourword_add should be an ADD followed by 3 ADDC's */ | |
1041 | Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, | |
1042 | opnd2p1<<3 | opnd2p2>>29, opnd2p2<<3, 0, 0); | |
1043 | } | |
1044 | if (Dbit29p2(opnd1p2)) { | |
1045 | Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, | |
1046 | opnd2p1<<2 | opnd2p2>>30, opnd2p2<<2, 0, 0); | |
1047 | } | |
1048 | if (Dbit30p2(opnd1p2)) { | |
1049 | Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, | |
1050 | opnd2p1<<1 | opnd2p2>>31, opnd2p2<<1, 0, 0); | |
1051 | } | |
1052 | if (Dbit31p2(opnd1p2)) { | |
1053 | Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, | |
1054 | opnd2p1, opnd2p2, 0, 0); | |
1055 | } | |
1056 | Dbl_rightshiftby4(opnd1p1,opnd1p2); | |
1057 | } | |
1058 | if (Is_dexthiddenoverflow(tmpresp1)) { | |
1059 | /* result mantissa >= 2 (mantissa overflow) */ | |
1060 | mpy_exponent++; | |
1061 | Dblext_rightshiftby1(tmpresp1,tmpresp2,tmpresp3,tmpresp4); | |
1062 | } | |
1063 | ||
1064 | /* | |
1065 | * Restore the sign of the mpy result which was saved in resultp1. | |
1066 | * The exponent will continue to be kept in mpy_exponent. | |
1067 | */ | |
1068 | Dblext_set_sign(tmpresp1,Dbl_sign(resultp1)); | |
1069 | ||
1070 | /* | |
1071 | * No rounding is required, since the result of the multiply | |
1072 | * is exact in the extended format. | |
1073 | */ | |
1074 | ||
1075 | /* | |
1076 | * Now we are ready to perform the add portion of the operation. | |
1077 | * | |
1078 | * The exponents need to be kept as integers for now, since the | |
1079 | * multiply result might not fit into the exponent field. We | |
1080 | * can't overflow or underflow because of this yet, since the | |
1081 | * add could bring the final result back into range. | |
1082 | */ | |
1083 | add_exponent = Dbl_exponent(opnd3p1); | |
1084 | ||
1085 | /* | |
1086 | * Check for denormalized or zero add operand. | |
1087 | */ | |
1088 | if (add_exponent == 0) { | |
1089 | /* check for zero */ | |
1090 | if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) { | |
1091 | /* right is zero */ | |
1092 | /* Left can't be zero and must be result. | |
1093 | * | |
1094 | * The final result is now in tmpres and mpy_exponent, | |
1095 | * and needs to be rounded and squeezed back into | |
1096 | * double precision format from double extended. | |
1097 | */ | |
1098 | result_exponent = mpy_exponent; | |
1099 | Dblext_copy(tmpresp1,tmpresp2,tmpresp3,tmpresp4, | |
1100 | resultp1,resultp2,resultp3,resultp4); | |
1101 | sign_save = Dbl_signextendedsign(resultp1);/*save sign*/ | |
1102 | goto round; | |
1103 | } | |
1104 | ||
1105 | /* | |
1106 | * Neither are zeroes. | |
1107 | * Adjust exponent and normalize add operand. | |
1108 | */ | |
1109 | sign_save = Dbl_signextendedsign(opnd3p1); /* save sign */ | |
1110 | Dbl_clear_signexponent(opnd3p1); | |
1111 | Dbl_leftshiftby1(opnd3p1,opnd3p2); | |
1112 | Dbl_normalize(opnd3p1,opnd3p2,add_exponent); | |
1113 | Dbl_set_sign(opnd3p1,sign_save); /* restore sign */ | |
1114 | } else { | |
1115 | Dbl_clear_exponent_set_hidden(opnd3p1); | |
1116 | } | |
1117 | /* | |
1118 | * Copy opnd3 to the double extended variable called right. | |
1119 | */ | |
1120 | Dbl_copyto_dblext(opnd3p1,opnd3p2,rightp1,rightp2,rightp3,rightp4); | |
1121 | ||
1122 | /* | |
1123 | * A zero "save" helps discover equal operands (for later), | |
1124 | * and is used in swapping operands (if needed). | |
1125 | */ | |
1126 | Dblext_xortointp1(tmpresp1,rightp1,/*to*/save); | |
1127 | ||
1128 | /* | |
1129 | * Compare magnitude of operands. | |
1130 | */ | |
1131 | Dblext_copytoint_exponentmantissap1(tmpresp1,signlessleft1); | |
1132 | Dblext_copytoint_exponentmantissap1(rightp1,signlessright1); | |
1133 | if (mpy_exponent < add_exponent || mpy_exponent == add_exponent && | |
1134 | Dblext_ismagnitudeless(tmpresp2,rightp2,signlessleft1,signlessright1)){ | |
1135 | /* | |
1136 | * Set the left operand to the larger one by XOR swap. | |
1137 | * First finish the first word "save". | |
1138 | */ | |
1139 | Dblext_xorfromintp1(save,rightp1,/*to*/rightp1); | |
1140 | Dblext_xorfromintp1(save,tmpresp1,/*to*/tmpresp1); | |
1141 | Dblext_swap_lower(tmpresp2,tmpresp3,tmpresp4, | |
1142 | rightp2,rightp3,rightp4); | |
1143 | /* also setup exponents used in rest of routine */ | |
1144 | diff_exponent = add_exponent - mpy_exponent; | |
1145 | result_exponent = add_exponent; | |
1146 | } else { | |
1147 | /* also setup exponents used in rest of routine */ | |
1148 | diff_exponent = mpy_exponent - add_exponent; | |
1149 | result_exponent = mpy_exponent; | |
1150 | } | |
1151 | /* Invariant: left is not smaller than right. */ | |
1152 | ||
1153 | /* | |
1154 | * Special case alignment of operands that would force alignment | |
1155 | * beyond the extent of the extension. A further optimization | |
1156 | * could special case this but only reduces the path length for | |
1157 | * this infrequent case. | |
1158 | */ | |
1159 | if (diff_exponent > DBLEXT_THRESHOLD) { | |
1160 | diff_exponent = DBLEXT_THRESHOLD; | |
1161 | } | |
1162 | ||
1163 | /* Align right operand by shifting it to the right */ | |
1164 | Dblext_clear_sign(rightp1); | |
1165 | Dblext_right_align(rightp1,rightp2,rightp3,rightp4, | |
1166 | /*shifted by*/diff_exponent); | |
1167 | ||
1168 | /* Treat sum and difference of the operands separately. */ | |
1169 | if ((int)save < 0) { | |
1170 | /* | |
1171 | * Difference of the two operands. Overflow can occur if the | |
1172 | * multiply overflowed. A borrow can occur out of the hidden | |
1173 | * bit and force a post normalization phase. | |
1174 | */ | |
1175 | Dblext_subtract(tmpresp1,tmpresp2,tmpresp3,tmpresp4, | |
1176 | rightp1,rightp2,rightp3,rightp4, | |
1177 | resultp1,resultp2,resultp3,resultp4); | |
1178 | sign_save = Dbl_signextendedsign(resultp1); | |
1179 | if (Dbl_iszero_hidden(resultp1)) { | |
1180 | /* Handle normalization */ | |
25985edc | 1181 | /* A straightforward algorithm would now shift the |
1da177e4 LT |
1182 | * result and extension left until the hidden bit |
1183 | * becomes one. Not all of the extension bits need | |
1184 | * participate in the shift. Only the two most | |
1185 | * significant bits (round and guard) are needed. | |
1186 | * If only a single shift is needed then the guard | |
1187 | * bit becomes a significant low order bit and the | |
1188 | * extension must participate in the rounding. | |
1189 | * If more than a single shift is needed, then all | |
1190 | * bits to the right of the guard bit are zeros, | |
1191 | * and the guard bit may or may not be zero. */ | |
1192 | Dblext_leftshiftby1(resultp1,resultp2,resultp3, | |
1193 | resultp4); | |
1194 | ||
1195 | /* Need to check for a zero result. The sign and | |
1196 | * exponent fields have already been zeroed. The more | |
1197 | * efficient test of the full object can be used. | |
1198 | */ | |
1199 | if (Dblext_iszero(resultp1,resultp2,resultp3,resultp4)) { | |
1200 | /* Must have been "x-x" or "x+(-x)". */ | |
1201 | if (Is_rounding_mode(ROUNDMINUS)) | |
1202 | Dbl_setone_sign(resultp1); | |
1203 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
1204 | return(NOEXCEPTION); | |
1205 | } | |
1206 | result_exponent--; | |
1207 | ||
1208 | /* Look to see if normalization is finished. */ | |
1209 | if (Dbl_isone_hidden(resultp1)) { | |
1210 | /* No further normalization is needed */ | |
1211 | goto round; | |
1212 | } | |
1213 | ||
1214 | /* Discover first one bit to determine shift amount. | |
1215 | * Use a modified binary search. We have already | |
1216 | * shifted the result one position right and still | |
1217 | * not found a one so the remainder of the extension | |
1218 | * must be zero and simplifies rounding. */ | |
1219 | /* Scan bytes */ | |
1220 | while (Dbl_iszero_hiddenhigh7mantissa(resultp1)) { | |
1221 | Dblext_leftshiftby8(resultp1,resultp2,resultp3,resultp4); | |
1222 | result_exponent -= 8; | |
1223 | } | |
1224 | /* Now narrow it down to the nibble */ | |
1225 | if (Dbl_iszero_hiddenhigh3mantissa(resultp1)) { | |
1226 | /* The lower nibble contains the | |
1227 | * normalizing one */ | |
1228 | Dblext_leftshiftby4(resultp1,resultp2,resultp3,resultp4); | |
1229 | result_exponent -= 4; | |
1230 | } | |
1231 | /* Select case where first bit is set (already | |
1232 | * normalized) otherwise select the proper shift. */ | |
1233 | jumpsize = Dbl_hiddenhigh3mantissa(resultp1); | |
1234 | if (jumpsize <= 7) switch(jumpsize) { | |
1235 | case 1: | |
1236 | Dblext_leftshiftby3(resultp1,resultp2,resultp3, | |
1237 | resultp4); | |
1238 | result_exponent -= 3; | |
1239 | break; | |
1240 | case 2: | |
1241 | case 3: | |
1242 | Dblext_leftshiftby2(resultp1,resultp2,resultp3, | |
1243 | resultp4); | |
1244 | result_exponent -= 2; | |
1245 | break; | |
1246 | case 4: | |
1247 | case 5: | |
1248 | case 6: | |
1249 | case 7: | |
1250 | Dblext_leftshiftby1(resultp1,resultp2,resultp3, | |
1251 | resultp4); | |
1252 | result_exponent -= 1; | |
1253 | break; | |
1254 | } | |
1255 | } /* end if (hidden...)... */ | |
1256 | /* Fall through and round */ | |
1257 | } /* end if (save < 0)... */ | |
1258 | else { | |
1259 | /* Add magnitudes */ | |
1260 | Dblext_addition(tmpresp1,tmpresp2,tmpresp3,tmpresp4, | |
1261 | rightp1,rightp2,rightp3,rightp4, | |
1262 | /*to*/resultp1,resultp2,resultp3,resultp4); | |
1263 | sign_save = Dbl_signextendedsign(resultp1); | |
1264 | if (Dbl_isone_hiddenoverflow(resultp1)) { | |
1265 | /* Prenormalization required. */ | |
1266 | Dblext_arithrightshiftby1(resultp1,resultp2,resultp3, | |
1267 | resultp4); | |
1268 | result_exponent++; | |
1269 | } /* end if hiddenoverflow... */ | |
1270 | } /* end else ...add magnitudes... */ | |
1271 | ||
1272 | /* Round the result. If the extension and lower two words are | |
1273 | * all zeros, then the result is exact. Otherwise round in the | |
1274 | * correct direction. Underflow is possible. If a postnormalization | |
1275 | * is necessary, then the mantissa is all zeros so no shift is needed. | |
1276 | */ | |
1277 | round: | |
1278 | if (result_exponent <= 0 && !Is_underflowtrap_enabled()) { | |
1279 | Dblext_denormalize(resultp1,resultp2,resultp3,resultp4, | |
1280 | result_exponent,is_tiny); | |
1281 | } | |
1282 | Dbl_set_sign(resultp1,/*using*/sign_save); | |
1283 | if (Dblext_isnotzero_mantissap3(resultp3) || | |
1284 | Dblext_isnotzero_mantissap4(resultp4)) { | |
1285 | inexact = TRUE; | |
1286 | switch(Rounding_mode()) { | |
1287 | case ROUNDNEAREST: /* The default. */ | |
1288 | if (Dblext_isone_highp3(resultp3)) { | |
1289 | /* at least 1/2 ulp */ | |
1290 | if (Dblext_isnotzero_low31p3(resultp3) || | |
1291 | Dblext_isnotzero_mantissap4(resultp4) || | |
1292 | Dblext_isone_lowp2(resultp2)) { | |
1293 | /* either exactly half way and odd or | |
1294 | * more than 1/2ulp */ | |
1295 | Dbl_increment(resultp1,resultp2); | |
1296 | } | |
1297 | } | |
1298 | break; | |
1299 | ||
1300 | case ROUNDPLUS: | |
1301 | if (Dbl_iszero_sign(resultp1)) { | |
1302 | /* Round up positive results */ | |
1303 | Dbl_increment(resultp1,resultp2); | |
1304 | } | |
1305 | break; | |
1306 | ||
1307 | case ROUNDMINUS: | |
1308 | if (Dbl_isone_sign(resultp1)) { | |
1309 | /* Round down negative results */ | |
1310 | Dbl_increment(resultp1,resultp2); | |
1311 | } | |
1312 | ||
1313 | case ROUNDZERO:; | |
1314 | /* truncate is simple */ | |
1315 | } /* end switch... */ | |
1316 | if (Dbl_isone_hiddenoverflow(resultp1)) result_exponent++; | |
1317 | } | |
1318 | if (result_exponent >= DBL_INFINITY_EXPONENT) { | |
1319 | /* Overflow */ | |
1320 | if (Is_overflowtrap_enabled()) { | |
1321 | /* | |
1322 | * Adjust bias of result | |
1323 | */ | |
1324 | Dbl_setwrapped_exponent(resultp1,result_exponent,ovfl); | |
1325 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
1326 | if (inexact) | |
1327 | if (Is_inexacttrap_enabled()) | |
1328 | return (OPC_2E_OVERFLOWEXCEPTION | | |
1329 | OPC_2E_INEXACTEXCEPTION); | |
1330 | else Set_inexactflag(); | |
1331 | return (OPC_2E_OVERFLOWEXCEPTION); | |
1332 | } | |
1333 | inexact = TRUE; | |
1334 | Set_overflowflag(); | |
1335 | Dbl_setoverflow(resultp1,resultp2); | |
1336 | } else if (result_exponent <= 0) { /* underflow case */ | |
1337 | if (Is_underflowtrap_enabled()) { | |
1338 | /* | |
1339 | * Adjust bias of result | |
1340 | */ | |
1341 | Dbl_setwrapped_exponent(resultp1,result_exponent,unfl); | |
1342 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
1343 | if (inexact) | |
1344 | if (Is_inexacttrap_enabled()) | |
1345 | return (OPC_2E_UNDERFLOWEXCEPTION | | |
1346 | OPC_2E_INEXACTEXCEPTION); | |
1347 | else Set_inexactflag(); | |
1348 | return(OPC_2E_UNDERFLOWEXCEPTION); | |
1349 | } | |
1350 | else if (inexact && is_tiny) Set_underflowflag(); | |
1351 | } | |
1352 | else Dbl_set_exponent(resultp1,result_exponent); | |
1353 | Dbl_copytoptr(resultp1,resultp2,dstptr); | |
1354 | if (inexact) | |
1355 | if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION); | |
1356 | else Set_inexactflag(); | |
1357 | return(NOEXCEPTION); | |
1358 | } | |
1359 | ||
1360 | /* | |
1361 | * Single Floating-point Multiply Fused Add | |
1362 | */ | |
1363 | ||
1364 | sgl_fmpyfadd(src1ptr,src2ptr,src3ptr,status,dstptr) | |
1365 | ||
1366 | sgl_floating_point *src1ptr, *src2ptr, *src3ptr, *dstptr; | |
1367 | unsigned int *status; | |
1368 | { | |
1369 | unsigned int opnd1, opnd2, opnd3; | |
1370 | register unsigned int tmpresp1, tmpresp2; | |
1371 | unsigned int rightp1, rightp2; | |
1372 | unsigned int resultp1, resultp2 = 0; | |
1373 | register int mpy_exponent, add_exponent, count; | |
1374 | boolean inexact = FALSE, is_tiny = FALSE; | |
1375 | ||
1376 | unsigned int signlessleft1, signlessright1, save; | |
1377 | register int result_exponent, diff_exponent; | |
1378 | int sign_save, jumpsize; | |
1379 | ||
1380 | Sgl_copyfromptr(src1ptr,opnd1); | |
1381 | Sgl_copyfromptr(src2ptr,opnd2); | |
1382 | Sgl_copyfromptr(src3ptr,opnd3); | |
1383 | ||
1384 | /* | |
1385 | * set sign bit of result of multiply | |
1386 | */ | |
1387 | if (Sgl_sign(opnd1) ^ Sgl_sign(opnd2)) | |
1388 | Sgl_setnegativezero(resultp1); | |
1389 | else Sgl_setzero(resultp1); | |
1390 | ||
1391 | /* | |
1392 | * Generate multiply exponent | |
1393 | */ | |
1394 | mpy_exponent = Sgl_exponent(opnd1) + Sgl_exponent(opnd2) - SGL_BIAS; | |
1395 | ||
1396 | /* | |
1397 | * check first operand for NaN's or infinity | |
1398 | */ | |
1399 | if (Sgl_isinfinity_exponent(opnd1)) { | |
1400 | if (Sgl_iszero_mantissa(opnd1)) { | |
1401 | if (Sgl_isnotnan(opnd2) && Sgl_isnotnan(opnd3)) { | |
1402 | if (Sgl_iszero_exponentmantissa(opnd2)) { | |
1403 | /* | |
1404 | * invalid since operands are infinity | |
1405 | * and zero | |
1406 | */ | |
1407 | if (Is_invalidtrap_enabled()) | |
1408 | return(OPC_2E_INVALIDEXCEPTION); | |
1409 | Set_invalidflag(); | |
1410 | Sgl_makequietnan(resultp1); | |
1411 | Sgl_copytoptr(resultp1,dstptr); | |
1412 | return(NOEXCEPTION); | |
1413 | } | |
1414 | /* | |
1415 | * Check third operand for infinity with a | |
1416 | * sign opposite of the multiply result | |
1417 | */ | |
1418 | if (Sgl_isinfinity(opnd3) && | |
1419 | (Sgl_sign(resultp1) ^ Sgl_sign(opnd3))) { | |
1420 | /* | |
1421 | * invalid since attempting a magnitude | |
1422 | * subtraction of infinities | |
1423 | */ | |
1424 | if (Is_invalidtrap_enabled()) | |
1425 | return(OPC_2E_INVALIDEXCEPTION); | |
1426 | Set_invalidflag(); | |
1427 | Sgl_makequietnan(resultp1); | |
1428 | Sgl_copytoptr(resultp1,dstptr); | |
1429 | return(NOEXCEPTION); | |
1430 | } | |
1431 | ||
1432 | /* | |
1433 | * return infinity | |
1434 | */ | |
1435 | Sgl_setinfinity_exponentmantissa(resultp1); | |
1436 | Sgl_copytoptr(resultp1,dstptr); | |
1437 | return(NOEXCEPTION); | |
1438 | } | |
1439 | } | |
1440 | else { | |
1441 | /* | |
1442 | * is NaN; signaling or quiet? | |
1443 | */ | |
1444 | if (Sgl_isone_signaling(opnd1)) { | |
1445 | /* trap if INVALIDTRAP enabled */ | |
1446 | if (Is_invalidtrap_enabled()) | |
1447 | return(OPC_2E_INVALIDEXCEPTION); | |
1448 | /* make NaN quiet */ | |
1449 | Set_invalidflag(); | |
1450 | Sgl_set_quiet(opnd1); | |
1451 | } | |
1452 | /* | |
1453 | * is second operand a signaling NaN? | |
1454 | */ | |
1455 | else if (Sgl_is_signalingnan(opnd2)) { | |
1456 | /* trap if INVALIDTRAP enabled */ | |
1457 | if (Is_invalidtrap_enabled()) | |
1458 | return(OPC_2E_INVALIDEXCEPTION); | |
1459 | /* make NaN quiet */ | |
1460 | Set_invalidflag(); | |
1461 | Sgl_set_quiet(opnd2); | |
1462 | Sgl_copytoptr(opnd2,dstptr); | |
1463 | return(NOEXCEPTION); | |
1464 | } | |
1465 | /* | |
1466 | * is third operand a signaling NaN? | |
1467 | */ | |
1468 | else if (Sgl_is_signalingnan(opnd3)) { | |
1469 | /* trap if INVALIDTRAP enabled */ | |
1470 | if (Is_invalidtrap_enabled()) | |
1471 | return(OPC_2E_INVALIDEXCEPTION); | |
1472 | /* make NaN quiet */ | |
1473 | Set_invalidflag(); | |
1474 | Sgl_set_quiet(opnd3); | |
1475 | Sgl_copytoptr(opnd3,dstptr); | |
1476 | return(NOEXCEPTION); | |
1477 | } | |
1478 | /* | |
1479 | * return quiet NaN | |
1480 | */ | |
1481 | Sgl_copytoptr(opnd1,dstptr); | |
1482 | return(NOEXCEPTION); | |
1483 | } | |
1484 | } | |
1485 | ||
1486 | /* | |
1487 | * check second operand for NaN's or infinity | |
1488 | */ | |
1489 | if (Sgl_isinfinity_exponent(opnd2)) { | |
1490 | if (Sgl_iszero_mantissa(opnd2)) { | |
1491 | if (Sgl_isnotnan(opnd3)) { | |
1492 | if (Sgl_iszero_exponentmantissa(opnd1)) { | |
1493 | /* | |
1494 | * invalid since multiply operands are | |
1495 | * zero & infinity | |
1496 | */ | |
1497 | if (Is_invalidtrap_enabled()) | |
1498 | return(OPC_2E_INVALIDEXCEPTION); | |
1499 | Set_invalidflag(); | |
1500 | Sgl_makequietnan(opnd2); | |
1501 | Sgl_copytoptr(opnd2,dstptr); | |
1502 | return(NOEXCEPTION); | |
1503 | } | |
1504 | ||
1505 | /* | |
1506 | * Check third operand for infinity with a | |
1507 | * sign opposite of the multiply result | |
1508 | */ | |
1509 | if (Sgl_isinfinity(opnd3) && | |
1510 | (Sgl_sign(resultp1) ^ Sgl_sign(opnd3))) { | |
1511 | /* | |
1512 | * invalid since attempting a magnitude | |
1513 | * subtraction of infinities | |
1514 | */ | |
1515 | if (Is_invalidtrap_enabled()) | |
1516 | return(OPC_2E_INVALIDEXCEPTION); | |
1517 | Set_invalidflag(); | |
1518 | Sgl_makequietnan(resultp1); | |
1519 | Sgl_copytoptr(resultp1,dstptr); | |
1520 | return(NOEXCEPTION); | |
1521 | } | |
1522 | ||
1523 | /* | |
1524 | * return infinity | |
1525 | */ | |
1526 | Sgl_setinfinity_exponentmantissa(resultp1); | |
1527 | Sgl_copytoptr(resultp1,dstptr); | |
1528 | return(NOEXCEPTION); | |
1529 | } | |
1530 | } | |
1531 | else { | |
1532 | /* | |
1533 | * is NaN; signaling or quiet? | |
1534 | */ | |
1535 | if (Sgl_isone_signaling(opnd2)) { | |
1536 | /* trap if INVALIDTRAP enabled */ | |
1537 | if (Is_invalidtrap_enabled()) | |
1538 | return(OPC_2E_INVALIDEXCEPTION); | |
1539 | /* make NaN quiet */ | |
1540 | Set_invalidflag(); | |
1541 | Sgl_set_quiet(opnd2); | |
1542 | } | |
1543 | /* | |
1544 | * is third operand a signaling NaN? | |
1545 | */ | |
1546 | else if (Sgl_is_signalingnan(opnd3)) { | |
1547 | /* trap if INVALIDTRAP enabled */ | |
1548 | if (Is_invalidtrap_enabled()) | |
1549 | return(OPC_2E_INVALIDEXCEPTION); | |
1550 | /* make NaN quiet */ | |
1551 | Set_invalidflag(); | |
1552 | Sgl_set_quiet(opnd3); | |
1553 | Sgl_copytoptr(opnd3,dstptr); | |
1554 | return(NOEXCEPTION); | |
1555 | } | |
1556 | /* | |
1557 | * return quiet NaN | |
1558 | */ | |
1559 | Sgl_copytoptr(opnd2,dstptr); | |
1560 | return(NOEXCEPTION); | |
1561 | } | |
1562 | } | |
1563 | ||
1564 | /* | |
1565 | * check third operand for NaN's or infinity | |
1566 | */ | |
1567 | if (Sgl_isinfinity_exponent(opnd3)) { | |
1568 | if (Sgl_iszero_mantissa(opnd3)) { | |
1569 | /* return infinity */ | |
1570 | Sgl_copytoptr(opnd3,dstptr); | |
1571 | return(NOEXCEPTION); | |
1572 | } else { | |
1573 | /* | |
1574 | * is NaN; signaling or quiet? | |
1575 | */ | |
1576 | if (Sgl_isone_signaling(opnd3)) { | |
1577 | /* trap if INVALIDTRAP enabled */ | |
1578 | if (Is_invalidtrap_enabled()) | |
1579 | return(OPC_2E_INVALIDEXCEPTION); | |
1580 | /* make NaN quiet */ | |
1581 | Set_invalidflag(); | |
1582 | Sgl_set_quiet(opnd3); | |
1583 | } | |
1584 | /* | |
1585 | * return quiet NaN | |
1586 | */ | |
1587 | Sgl_copytoptr(opnd3,dstptr); | |
1588 | return(NOEXCEPTION); | |
1589 | } | |
1590 | } | |
1591 | ||
1592 | /* | |
1593 | * Generate multiply mantissa | |
1594 | */ | |
1595 | if (Sgl_isnotzero_exponent(opnd1)) { | |
1596 | /* set hidden bit */ | |
1597 | Sgl_clear_signexponent_set_hidden(opnd1); | |
1598 | } | |
1599 | else { | |
1600 | /* check for zero */ | |
1601 | if (Sgl_iszero_mantissa(opnd1)) { | |
1602 | /* | |
1603 | * Perform the add opnd3 with zero here. | |
1604 | */ | |
1605 | if (Sgl_iszero_exponentmantissa(opnd3)) { | |
1606 | if (Is_rounding_mode(ROUNDMINUS)) { | |
1607 | Sgl_or_signs(opnd3,resultp1); | |
1608 | } else { | |
1609 | Sgl_and_signs(opnd3,resultp1); | |
1610 | } | |
1611 | } | |
1612 | /* | |
1613 | * Now let's check for trapped underflow case. | |
1614 | */ | |
1615 | else if (Sgl_iszero_exponent(opnd3) && | |
1616 | Is_underflowtrap_enabled()) { | |
1617 | /* need to normalize results mantissa */ | |
1618 | sign_save = Sgl_signextendedsign(opnd3); | |
1619 | result_exponent = 0; | |
1620 | Sgl_leftshiftby1(opnd3); | |
1621 | Sgl_normalize(opnd3,result_exponent); | |
1622 | Sgl_set_sign(opnd3,/*using*/sign_save); | |
1623 | Sgl_setwrapped_exponent(opnd3,result_exponent, | |
1624 | unfl); | |
1625 | Sgl_copytoptr(opnd3,dstptr); | |
1626 | /* inexact = FALSE */ | |
1627 | return(OPC_2E_UNDERFLOWEXCEPTION); | |
1628 | } | |
1629 | Sgl_copytoptr(opnd3,dstptr); | |
1630 | return(NOEXCEPTION); | |
1631 | } | |
1632 | /* is denormalized, adjust exponent */ | |
1633 | Sgl_clear_signexponent(opnd1); | |
1634 | Sgl_leftshiftby1(opnd1); | |
1635 | Sgl_normalize(opnd1,mpy_exponent); | |
1636 | } | |
1637 | /* opnd2 needs to have hidden bit set with msb in hidden bit */ | |
1638 | if (Sgl_isnotzero_exponent(opnd2)) { | |
1639 | Sgl_clear_signexponent_set_hidden(opnd2); | |
1640 | } | |
1641 | else { | |
1642 | /* check for zero */ | |
1643 | if (Sgl_iszero_mantissa(opnd2)) { | |
1644 | /* | |
1645 | * Perform the add opnd3 with zero here. | |
1646 | */ | |
1647 | if (Sgl_iszero_exponentmantissa(opnd3)) { | |
1648 | if (Is_rounding_mode(ROUNDMINUS)) { | |
1649 | Sgl_or_signs(opnd3,resultp1); | |
1650 | } else { | |
1651 | Sgl_and_signs(opnd3,resultp1); | |
1652 | } | |
1653 | } | |
1654 | /* | |
1655 | * Now let's check for trapped underflow case. | |
1656 | */ | |
1657 | else if (Sgl_iszero_exponent(opnd3) && | |
1658 | Is_underflowtrap_enabled()) { | |
1659 | /* need to normalize results mantissa */ | |
1660 | sign_save = Sgl_signextendedsign(opnd3); | |
1661 | result_exponent = 0; | |
1662 | Sgl_leftshiftby1(opnd3); | |
1663 | Sgl_normalize(opnd3,result_exponent); | |
1664 | Sgl_set_sign(opnd3,/*using*/sign_save); | |
1665 | Sgl_setwrapped_exponent(opnd3,result_exponent, | |
1666 | unfl); | |
1667 | Sgl_copytoptr(opnd3,dstptr); | |
1668 | /* inexact = FALSE */ | |
1669 | return(OPC_2E_UNDERFLOWEXCEPTION); | |
1670 | } | |
1671 | Sgl_copytoptr(opnd3,dstptr); | |
1672 | return(NOEXCEPTION); | |
1673 | } | |
1674 | /* is denormalized; want to normalize */ | |
1675 | Sgl_clear_signexponent(opnd2); | |
1676 | Sgl_leftshiftby1(opnd2); | |
1677 | Sgl_normalize(opnd2,mpy_exponent); | |
1678 | } | |
1679 | ||
1680 | /* Multiply the first two source mantissas together */ | |
1681 | ||
1682 | /* | |
1683 | * The intermediate result will be kept in tmpres, | |
1684 | * which needs enough room for 106 bits of mantissa, | |
1685 | * so lets call it a Double extended. | |
1686 | */ | |
1687 | Sglext_setzero(tmpresp1,tmpresp2); | |
1688 | ||
1689 | /* | |
1690 | * Four bits at a time are inspected in each loop, and a | |
1691 | * simple shift and add multiply algorithm is used. | |
1692 | */ | |
1693 | for (count = SGL_P-1; count >= 0; count -= 4) { | |
1694 | Sglext_rightshiftby4(tmpresp1,tmpresp2); | |
1695 | if (Sbit28(opnd1)) { | |
1696 | /* Twoword_add should be an ADD followed by 2 ADDC's */ | |
1697 | Twoword_add(tmpresp1, tmpresp2, opnd2<<3, 0); | |
1698 | } | |
1699 | if (Sbit29(opnd1)) { | |
1700 | Twoword_add(tmpresp1, tmpresp2, opnd2<<2, 0); | |
1701 | } | |
1702 | if (Sbit30(opnd1)) { | |
1703 | Twoword_add(tmpresp1, tmpresp2, opnd2<<1, 0); | |
1704 | } | |
1705 | if (Sbit31(opnd1)) { | |
1706 | Twoword_add(tmpresp1, tmpresp2, opnd2, 0); | |
1707 | } | |
1708 | Sgl_rightshiftby4(opnd1); | |
1709 | } | |
1710 | if (Is_sexthiddenoverflow(tmpresp1)) { | |
1711 | /* result mantissa >= 2 (mantissa overflow) */ | |
1712 | mpy_exponent++; | |
1713 | Sglext_rightshiftby4(tmpresp1,tmpresp2); | |
1714 | } else { | |
1715 | Sglext_rightshiftby3(tmpresp1,tmpresp2); | |
1716 | } | |
1717 | ||
1718 | /* | |
1719 | * Restore the sign of the mpy result which was saved in resultp1. | |
1720 | * The exponent will continue to be kept in mpy_exponent. | |
1721 | */ | |
1722 | Sglext_set_sign(tmpresp1,Sgl_sign(resultp1)); | |
1723 | ||
1724 | /* | |
1725 | * No rounding is required, since the result of the multiply | |
1726 | * is exact in the extended format. | |
1727 | */ | |
1728 | ||
1729 | /* | |
1730 | * Now we are ready to perform the add portion of the operation. | |
1731 | * | |
1732 | * The exponents need to be kept as integers for now, since the | |
1733 | * multiply result might not fit into the exponent field. We | |
1734 | * can't overflow or underflow because of this yet, since the | |
1735 | * add could bring the final result back into range. | |
1736 | */ | |
1737 | add_exponent = Sgl_exponent(opnd3); | |
1738 | ||
1739 | /* | |
1740 | * Check for denormalized or zero add operand. | |
1741 | */ | |
1742 | if (add_exponent == 0) { | |
1743 | /* check for zero */ | |
1744 | if (Sgl_iszero_mantissa(opnd3)) { | |
1745 | /* right is zero */ | |
1746 | /* Left can't be zero and must be result. | |
1747 | * | |
1748 | * The final result is now in tmpres and mpy_exponent, | |
1749 | * and needs to be rounded and squeezed back into | |
1750 | * double precision format from double extended. | |
1751 | */ | |
1752 | result_exponent = mpy_exponent; | |
1753 | Sglext_copy(tmpresp1,tmpresp2,resultp1,resultp2); | |
1754 | sign_save = Sgl_signextendedsign(resultp1);/*save sign*/ | |
1755 | goto round; | |
1756 | } | |
1757 | ||
1758 | /* | |
1759 | * Neither are zeroes. | |
1760 | * Adjust exponent and normalize add operand. | |
1761 | */ | |
1762 | sign_save = Sgl_signextendedsign(opnd3); /* save sign */ | |
1763 | Sgl_clear_signexponent(opnd3); | |
1764 | Sgl_leftshiftby1(opnd3); | |
1765 | Sgl_normalize(opnd3,add_exponent); | |
1766 | Sgl_set_sign(opnd3,sign_save); /* restore sign */ | |
1767 | } else { | |
1768 | Sgl_clear_exponent_set_hidden(opnd3); | |
1769 | } | |
1770 | /* | |
1771 | * Copy opnd3 to the double extended variable called right. | |
1772 | */ | |
1773 | Sgl_copyto_sglext(opnd3,rightp1,rightp2); | |
1774 | ||
1775 | /* | |
1776 | * A zero "save" helps discover equal operands (for later), | |
1777 | * and is used in swapping operands (if needed). | |
1778 | */ | |
1779 | Sglext_xortointp1(tmpresp1,rightp1,/*to*/save); | |
1780 | ||
1781 | /* | |
1782 | * Compare magnitude of operands. | |
1783 | */ | |
1784 | Sglext_copytoint_exponentmantissa(tmpresp1,signlessleft1); | |
1785 | Sglext_copytoint_exponentmantissa(rightp1,signlessright1); | |
1786 | if (mpy_exponent < add_exponent || mpy_exponent == add_exponent && | |
1787 | Sglext_ismagnitudeless(signlessleft1,signlessright1)) { | |
1788 | /* | |
1789 | * Set the left operand to the larger one by XOR swap. | |
1790 | * First finish the first word "save". | |
1791 | */ | |
1792 | Sglext_xorfromintp1(save,rightp1,/*to*/rightp1); | |
1793 | Sglext_xorfromintp1(save,tmpresp1,/*to*/tmpresp1); | |
1794 | Sglext_swap_lower(tmpresp2,rightp2); | |
1795 | /* also setup exponents used in rest of routine */ | |
1796 | diff_exponent = add_exponent - mpy_exponent; | |
1797 | result_exponent = add_exponent; | |
1798 | } else { | |
1799 | /* also setup exponents used in rest of routine */ | |
1800 | diff_exponent = mpy_exponent - add_exponent; | |
1801 | result_exponent = mpy_exponent; | |
1802 | } | |
1803 | /* Invariant: left is not smaller than right. */ | |
1804 | ||
1805 | /* | |
1806 | * Special case alignment of operands that would force alignment | |
1807 | * beyond the extent of the extension. A further optimization | |
1808 | * could special case this but only reduces the path length for | |
1809 | * this infrequent case. | |
1810 | */ | |
1811 | if (diff_exponent > SGLEXT_THRESHOLD) { | |
1812 | diff_exponent = SGLEXT_THRESHOLD; | |
1813 | } | |
1814 | ||
1815 | /* Align right operand by shifting it to the right */ | |
1816 | Sglext_clear_sign(rightp1); | |
1817 | Sglext_right_align(rightp1,rightp2,/*shifted by*/diff_exponent); | |
1818 | ||
1819 | /* Treat sum and difference of the operands separately. */ | |
1820 | if ((int)save < 0) { | |
1821 | /* | |
1822 | * Difference of the two operands. Overflow can occur if the | |
1823 | * multiply overflowed. A borrow can occur out of the hidden | |
1824 | * bit and force a post normalization phase. | |
1825 | */ | |
1826 | Sglext_subtract(tmpresp1,tmpresp2, rightp1,rightp2, | |
1827 | resultp1,resultp2); | |
1828 | sign_save = Sgl_signextendedsign(resultp1); | |
1829 | if (Sgl_iszero_hidden(resultp1)) { | |
1830 | /* Handle normalization */ | |
25985edc | 1831 | /* A straightforward algorithm would now shift the |
1da177e4 LT |
1832 | * result and extension left until the hidden bit |
1833 | * becomes one. Not all of the extension bits need | |
1834 | * participate in the shift. Only the two most | |
1835 | * significant bits (round and guard) are needed. | |
1836 | * If only a single shift is needed then the guard | |
1837 | * bit becomes a significant low order bit and the | |
1838 | * extension must participate in the rounding. | |
1839 | * If more than a single shift is needed, then all | |
1840 | * bits to the right of the guard bit are zeros, | |
1841 | * and the guard bit may or may not be zero. */ | |
1842 | Sglext_leftshiftby1(resultp1,resultp2); | |
1843 | ||
1844 | /* Need to check for a zero result. The sign and | |
1845 | * exponent fields have already been zeroed. The more | |
1846 | * efficient test of the full object can be used. | |
1847 | */ | |
1848 | if (Sglext_iszero(resultp1,resultp2)) { | |
1849 | /* Must have been "x-x" or "x+(-x)". */ | |
1850 | if (Is_rounding_mode(ROUNDMINUS)) | |
1851 | Sgl_setone_sign(resultp1); | |
1852 | Sgl_copytoptr(resultp1,dstptr); | |
1853 | return(NOEXCEPTION); | |
1854 | } | |
1855 | result_exponent--; | |
1856 | ||
1857 | /* Look to see if normalization is finished. */ | |
1858 | if (Sgl_isone_hidden(resultp1)) { | |
1859 | /* No further normalization is needed */ | |
1860 | goto round; | |
1861 | } | |
1862 | ||
1863 | /* Discover first one bit to determine shift amount. | |
1864 | * Use a modified binary search. We have already | |
1865 | * shifted the result one position right and still | |
1866 | * not found a one so the remainder of the extension | |
1867 | * must be zero and simplifies rounding. */ | |
1868 | /* Scan bytes */ | |
1869 | while (Sgl_iszero_hiddenhigh7mantissa(resultp1)) { | |
1870 | Sglext_leftshiftby8(resultp1,resultp2); | |
1871 | result_exponent -= 8; | |
1872 | } | |
1873 | /* Now narrow it down to the nibble */ | |
1874 | if (Sgl_iszero_hiddenhigh3mantissa(resultp1)) { | |
1875 | /* The lower nibble contains the | |
1876 | * normalizing one */ | |
1877 | Sglext_leftshiftby4(resultp1,resultp2); | |
1878 | result_exponent -= 4; | |
1879 | } | |
1880 | /* Select case where first bit is set (already | |
1881 | * normalized) otherwise select the proper shift. */ | |
1882 | jumpsize = Sgl_hiddenhigh3mantissa(resultp1); | |
1883 | if (jumpsize <= 7) switch(jumpsize) { | |
1884 | case 1: | |
1885 | Sglext_leftshiftby3(resultp1,resultp2); | |
1886 | result_exponent -= 3; | |
1887 | break; | |
1888 | case 2: | |
1889 | case 3: | |
1890 | Sglext_leftshiftby2(resultp1,resultp2); | |
1891 | result_exponent -= 2; | |
1892 | break; | |
1893 | case 4: | |
1894 | case 5: | |
1895 | case 6: | |
1896 | case 7: | |
1897 | Sglext_leftshiftby1(resultp1,resultp2); | |
1898 | result_exponent -= 1; | |
1899 | break; | |
1900 | } | |
1901 | } /* end if (hidden...)... */ | |
1902 | /* Fall through and round */ | |
1903 | } /* end if (save < 0)... */ | |
1904 | else { | |
1905 | /* Add magnitudes */ | |
1906 | Sglext_addition(tmpresp1,tmpresp2, | |
1907 | rightp1,rightp2, /*to*/resultp1,resultp2); | |
1908 | sign_save = Sgl_signextendedsign(resultp1); | |
1909 | if (Sgl_isone_hiddenoverflow(resultp1)) { | |
1910 | /* Prenormalization required. */ | |
1911 | Sglext_arithrightshiftby1(resultp1,resultp2); | |
1912 | result_exponent++; | |
1913 | } /* end if hiddenoverflow... */ | |
1914 | } /* end else ...add magnitudes... */ | |
1915 | ||
1916 | /* Round the result. If the extension and lower two words are | |
1917 | * all zeros, then the result is exact. Otherwise round in the | |
1918 | * correct direction. Underflow is possible. If a postnormalization | |
1919 | * is necessary, then the mantissa is all zeros so no shift is needed. | |
1920 | */ | |
1921 | round: | |
1922 | if (result_exponent <= 0 && !Is_underflowtrap_enabled()) { | |
1923 | Sglext_denormalize(resultp1,resultp2,result_exponent,is_tiny); | |
1924 | } | |
1925 | Sgl_set_sign(resultp1,/*using*/sign_save); | |
1926 | if (Sglext_isnotzero_mantissap2(resultp2)) { | |
1927 | inexact = TRUE; | |
1928 | switch(Rounding_mode()) { | |
1929 | case ROUNDNEAREST: /* The default. */ | |
1930 | if (Sglext_isone_highp2(resultp2)) { | |
1931 | /* at least 1/2 ulp */ | |
1932 | if (Sglext_isnotzero_low31p2(resultp2) || | |
1933 | Sglext_isone_lowp1(resultp1)) { | |
1934 | /* either exactly half way and odd or | |
1935 | * more than 1/2ulp */ | |
1936 | Sgl_increment(resultp1); | |
1937 | } | |
1938 | } | |
1939 | break; | |
1940 | ||
1941 | case ROUNDPLUS: | |
1942 | if (Sgl_iszero_sign(resultp1)) { | |
1943 | /* Round up positive results */ | |
1944 | Sgl_increment(resultp1); | |
1945 | } | |
1946 | break; | |
1947 | ||
1948 | case ROUNDMINUS: | |
1949 | if (Sgl_isone_sign(resultp1)) { | |
1950 | /* Round down negative results */ | |
1951 | Sgl_increment(resultp1); | |
1952 | } | |
1953 | ||
1954 | case ROUNDZERO:; | |
1955 | /* truncate is simple */ | |
1956 | } /* end switch... */ | |
1957 | if (Sgl_isone_hiddenoverflow(resultp1)) result_exponent++; | |
1958 | } | |
1959 | if (result_exponent >= SGL_INFINITY_EXPONENT) { | |
1960 | /* Overflow */ | |
1961 | if (Is_overflowtrap_enabled()) { | |
1962 | /* | |
1963 | * Adjust bias of result | |
1964 | */ | |
1965 | Sgl_setwrapped_exponent(resultp1,result_exponent,ovfl); | |
1966 | Sgl_copytoptr(resultp1,dstptr); | |
1967 | if (inexact) | |
1968 | if (Is_inexacttrap_enabled()) | |
1969 | return (OPC_2E_OVERFLOWEXCEPTION | | |
1970 | OPC_2E_INEXACTEXCEPTION); | |
1971 | else Set_inexactflag(); | |
1972 | return (OPC_2E_OVERFLOWEXCEPTION); | |
1973 | } | |
1974 | inexact = TRUE; | |
1975 | Set_overflowflag(); | |
1976 | Sgl_setoverflow(resultp1); | |
1977 | } else if (result_exponent <= 0) { /* underflow case */ | |
1978 | if (Is_underflowtrap_enabled()) { | |
1979 | /* | |
1980 | * Adjust bias of result | |
1981 | */ | |
1982 | Sgl_setwrapped_exponent(resultp1,result_exponent,unfl); | |
1983 | Sgl_copytoptr(resultp1,dstptr); | |
1984 | if (inexact) | |
1985 | if (Is_inexacttrap_enabled()) | |
1986 | return (OPC_2E_UNDERFLOWEXCEPTION | | |
1987 | OPC_2E_INEXACTEXCEPTION); | |
1988 | else Set_inexactflag(); | |
1989 | return(OPC_2E_UNDERFLOWEXCEPTION); | |
1990 | } | |
1991 | else if (inexact && is_tiny) Set_underflowflag(); | |
1992 | } | |
1993 | else Sgl_set_exponent(resultp1,result_exponent); | |
1994 | Sgl_copytoptr(resultp1,dstptr); | |
1995 | if (inexact) | |
1996 | if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION); | |
1997 | else Set_inexactflag(); | |
1998 | return(NOEXCEPTION); | |
1999 | } | |
2000 | ||
2001 | /* | |
2002 | * Single Floating-point Multiply Negate Fused Add | |
2003 | */ | |
2004 | ||
2005 | sgl_fmpynfadd(src1ptr,src2ptr,src3ptr,status,dstptr) | |
2006 | ||
2007 | sgl_floating_point *src1ptr, *src2ptr, *src3ptr, *dstptr; | |
2008 | unsigned int *status; | |
2009 | { | |
2010 | unsigned int opnd1, opnd2, opnd3; | |
2011 | register unsigned int tmpresp1, tmpresp2; | |
2012 | unsigned int rightp1, rightp2; | |
2013 | unsigned int resultp1, resultp2 = 0; | |
2014 | register int mpy_exponent, add_exponent, count; | |
2015 | boolean inexact = FALSE, is_tiny = FALSE; | |
2016 | ||
2017 | unsigned int signlessleft1, signlessright1, save; | |
2018 | register int result_exponent, diff_exponent; | |
2019 | int sign_save, jumpsize; | |
2020 | ||
2021 | Sgl_copyfromptr(src1ptr,opnd1); | |
2022 | Sgl_copyfromptr(src2ptr,opnd2); | |
2023 | Sgl_copyfromptr(src3ptr,opnd3); | |
2024 | ||
2025 | /* | |
2026 | * set sign bit of result of multiply | |
2027 | */ | |
2028 | if (Sgl_sign(opnd1) ^ Sgl_sign(opnd2)) | |
2029 | Sgl_setzero(resultp1); | |
2030 | else | |
2031 | Sgl_setnegativezero(resultp1); | |
2032 | ||
2033 | /* | |
2034 | * Generate multiply exponent | |
2035 | */ | |
2036 | mpy_exponent = Sgl_exponent(opnd1) + Sgl_exponent(opnd2) - SGL_BIAS; | |
2037 | ||
2038 | /* | |
2039 | * check first operand for NaN's or infinity | |
2040 | */ | |
2041 | if (Sgl_isinfinity_exponent(opnd1)) { | |
2042 | if (Sgl_iszero_mantissa(opnd1)) { | |
2043 | if (Sgl_isnotnan(opnd2) && Sgl_isnotnan(opnd3)) { | |
2044 | if (Sgl_iszero_exponentmantissa(opnd2)) { | |
2045 | /* | |
2046 | * invalid since operands are infinity | |
2047 | * and zero | |
2048 | */ | |
2049 | if (Is_invalidtrap_enabled()) | |
2050 | return(OPC_2E_INVALIDEXCEPTION); | |
2051 | Set_invalidflag(); | |
2052 | Sgl_makequietnan(resultp1); | |
2053 | Sgl_copytoptr(resultp1,dstptr); | |
2054 | return(NOEXCEPTION); | |
2055 | } | |
2056 | /* | |
2057 | * Check third operand for infinity with a | |
2058 | * sign opposite of the multiply result | |
2059 | */ | |
2060 | if (Sgl_isinfinity(opnd3) && | |
2061 | (Sgl_sign(resultp1) ^ Sgl_sign(opnd3))) { | |
2062 | /* | |
2063 | * invalid since attempting a magnitude | |
2064 | * subtraction of infinities | |
2065 | */ | |
2066 | if (Is_invalidtrap_enabled()) | |
2067 | return(OPC_2E_INVALIDEXCEPTION); | |
2068 | Set_invalidflag(); | |
2069 | Sgl_makequietnan(resultp1); | |
2070 | Sgl_copytoptr(resultp1,dstptr); | |
2071 | return(NOEXCEPTION); | |
2072 | } | |
2073 | ||
2074 | /* | |
2075 | * return infinity | |
2076 | */ | |
2077 | Sgl_setinfinity_exponentmantissa(resultp1); | |
2078 | Sgl_copytoptr(resultp1,dstptr); | |
2079 | return(NOEXCEPTION); | |
2080 | } | |
2081 | } | |
2082 | else { | |
2083 | /* | |
2084 | * is NaN; signaling or quiet? | |
2085 | */ | |
2086 | if (Sgl_isone_signaling(opnd1)) { | |
2087 | /* trap if INVALIDTRAP enabled */ | |
2088 | if (Is_invalidtrap_enabled()) | |
2089 | return(OPC_2E_INVALIDEXCEPTION); | |
2090 | /* make NaN quiet */ | |
2091 | Set_invalidflag(); | |
2092 | Sgl_set_quiet(opnd1); | |
2093 | } | |
2094 | /* | |
2095 | * is second operand a signaling NaN? | |
2096 | */ | |
2097 | else if (Sgl_is_signalingnan(opnd2)) { | |
2098 | /* trap if INVALIDTRAP enabled */ | |
2099 | if (Is_invalidtrap_enabled()) | |
2100 | return(OPC_2E_INVALIDEXCEPTION); | |
2101 | /* make NaN quiet */ | |
2102 | Set_invalidflag(); | |
2103 | Sgl_set_quiet(opnd2); | |
2104 | Sgl_copytoptr(opnd2,dstptr); | |
2105 | return(NOEXCEPTION); | |
2106 | } | |
2107 | /* | |
2108 | * is third operand a signaling NaN? | |
2109 | */ | |
2110 | else if (Sgl_is_signalingnan(opnd3)) { | |
2111 | /* trap if INVALIDTRAP enabled */ | |
2112 | if (Is_invalidtrap_enabled()) | |
2113 | return(OPC_2E_INVALIDEXCEPTION); | |
2114 | /* make NaN quiet */ | |
2115 | Set_invalidflag(); | |
2116 | Sgl_set_quiet(opnd3); | |
2117 | Sgl_copytoptr(opnd3,dstptr); | |
2118 | return(NOEXCEPTION); | |
2119 | } | |
2120 | /* | |
2121 | * return quiet NaN | |
2122 | */ | |
2123 | Sgl_copytoptr(opnd1,dstptr); | |
2124 | return(NOEXCEPTION); | |
2125 | } | |
2126 | } | |
2127 | ||
2128 | /* | |
2129 | * check second operand for NaN's or infinity | |
2130 | */ | |
2131 | if (Sgl_isinfinity_exponent(opnd2)) { | |
2132 | if (Sgl_iszero_mantissa(opnd2)) { | |
2133 | if (Sgl_isnotnan(opnd3)) { | |
2134 | if (Sgl_iszero_exponentmantissa(opnd1)) { | |
2135 | /* | |
2136 | * invalid since multiply operands are | |
2137 | * zero & infinity | |
2138 | */ | |
2139 | if (Is_invalidtrap_enabled()) | |
2140 | return(OPC_2E_INVALIDEXCEPTION); | |
2141 | Set_invalidflag(); | |
2142 | Sgl_makequietnan(opnd2); | |
2143 | Sgl_copytoptr(opnd2,dstptr); | |
2144 | return(NOEXCEPTION); | |
2145 | } | |
2146 | ||
2147 | /* | |
2148 | * Check third operand for infinity with a | |
2149 | * sign opposite of the multiply result | |
2150 | */ | |
2151 | if (Sgl_isinfinity(opnd3) && | |
2152 | (Sgl_sign(resultp1) ^ Sgl_sign(opnd3))) { | |
2153 | /* | |
2154 | * invalid since attempting a magnitude | |
2155 | * subtraction of infinities | |
2156 | */ | |
2157 | if (Is_invalidtrap_enabled()) | |
2158 | return(OPC_2E_INVALIDEXCEPTION); | |
2159 | Set_invalidflag(); | |
2160 | Sgl_makequietnan(resultp1); | |
2161 | Sgl_copytoptr(resultp1,dstptr); | |
2162 | return(NOEXCEPTION); | |
2163 | } | |
2164 | ||
2165 | /* | |
2166 | * return infinity | |
2167 | */ | |
2168 | Sgl_setinfinity_exponentmantissa(resultp1); | |
2169 | Sgl_copytoptr(resultp1,dstptr); | |
2170 | return(NOEXCEPTION); | |
2171 | } | |
2172 | } | |
2173 | else { | |
2174 | /* | |
2175 | * is NaN; signaling or quiet? | |
2176 | */ | |
2177 | if (Sgl_isone_signaling(opnd2)) { | |
2178 | /* trap if INVALIDTRAP enabled */ | |
2179 | if (Is_invalidtrap_enabled()) | |
2180 | return(OPC_2E_INVALIDEXCEPTION); | |
2181 | /* make NaN quiet */ | |
2182 | Set_invalidflag(); | |
2183 | Sgl_set_quiet(opnd2); | |
2184 | } | |
2185 | /* | |
2186 | * is third operand a signaling NaN? | |
2187 | */ | |
2188 | else if (Sgl_is_signalingnan(opnd3)) { | |
2189 | /* trap if INVALIDTRAP enabled */ | |
2190 | if (Is_invalidtrap_enabled()) | |
2191 | return(OPC_2E_INVALIDEXCEPTION); | |
2192 | /* make NaN quiet */ | |
2193 | Set_invalidflag(); | |
2194 | Sgl_set_quiet(opnd3); | |
2195 | Sgl_copytoptr(opnd3,dstptr); | |
2196 | return(NOEXCEPTION); | |
2197 | } | |
2198 | /* | |
2199 | * return quiet NaN | |
2200 | */ | |
2201 | Sgl_copytoptr(opnd2,dstptr); | |
2202 | return(NOEXCEPTION); | |
2203 | } | |
2204 | } | |
2205 | ||
2206 | /* | |
2207 | * check third operand for NaN's or infinity | |
2208 | */ | |
2209 | if (Sgl_isinfinity_exponent(opnd3)) { | |
2210 | if (Sgl_iszero_mantissa(opnd3)) { | |
2211 | /* return infinity */ | |
2212 | Sgl_copytoptr(opnd3,dstptr); | |
2213 | return(NOEXCEPTION); | |
2214 | } else { | |
2215 | /* | |
2216 | * is NaN; signaling or quiet? | |
2217 | */ | |
2218 | if (Sgl_isone_signaling(opnd3)) { | |
2219 | /* trap if INVALIDTRAP enabled */ | |
2220 | if (Is_invalidtrap_enabled()) | |
2221 | return(OPC_2E_INVALIDEXCEPTION); | |
2222 | /* make NaN quiet */ | |
2223 | Set_invalidflag(); | |
2224 | Sgl_set_quiet(opnd3); | |
2225 | } | |
2226 | /* | |
2227 | * return quiet NaN | |
2228 | */ | |
2229 | Sgl_copytoptr(opnd3,dstptr); | |
2230 | return(NOEXCEPTION); | |
2231 | } | |
2232 | } | |
2233 | ||
2234 | /* | |
2235 | * Generate multiply mantissa | |
2236 | */ | |
2237 | if (Sgl_isnotzero_exponent(opnd1)) { | |
2238 | /* set hidden bit */ | |
2239 | Sgl_clear_signexponent_set_hidden(opnd1); | |
2240 | } | |
2241 | else { | |
2242 | /* check for zero */ | |
2243 | if (Sgl_iszero_mantissa(opnd1)) { | |
2244 | /* | |
2245 | * Perform the add opnd3 with zero here. | |
2246 | */ | |
2247 | if (Sgl_iszero_exponentmantissa(opnd3)) { | |
2248 | if (Is_rounding_mode(ROUNDMINUS)) { | |
2249 | Sgl_or_signs(opnd3,resultp1); | |
2250 | } else { | |
2251 | Sgl_and_signs(opnd3,resultp1); | |
2252 | } | |
2253 | } | |
2254 | /* | |
2255 | * Now let's check for trapped underflow case. | |
2256 | */ | |
2257 | else if (Sgl_iszero_exponent(opnd3) && | |
2258 | Is_underflowtrap_enabled()) { | |
2259 | /* need to normalize results mantissa */ | |
2260 | sign_save = Sgl_signextendedsign(opnd3); | |
2261 | result_exponent = 0; | |
2262 | Sgl_leftshiftby1(opnd3); | |
2263 | Sgl_normalize(opnd3,result_exponent); | |
2264 | Sgl_set_sign(opnd3,/*using*/sign_save); | |
2265 | Sgl_setwrapped_exponent(opnd3,result_exponent, | |
2266 | unfl); | |
2267 | Sgl_copytoptr(opnd3,dstptr); | |
2268 | /* inexact = FALSE */ | |
2269 | return(OPC_2E_UNDERFLOWEXCEPTION); | |
2270 | } | |
2271 | Sgl_copytoptr(opnd3,dstptr); | |
2272 | return(NOEXCEPTION); | |
2273 | } | |
2274 | /* is denormalized, adjust exponent */ | |
2275 | Sgl_clear_signexponent(opnd1); | |
2276 | Sgl_leftshiftby1(opnd1); | |
2277 | Sgl_normalize(opnd1,mpy_exponent); | |
2278 | } | |
2279 | /* opnd2 needs to have hidden bit set with msb in hidden bit */ | |
2280 | if (Sgl_isnotzero_exponent(opnd2)) { | |
2281 | Sgl_clear_signexponent_set_hidden(opnd2); | |
2282 | } | |
2283 | else { | |
2284 | /* check for zero */ | |
2285 | if (Sgl_iszero_mantissa(opnd2)) { | |
2286 | /* | |
2287 | * Perform the add opnd3 with zero here. | |
2288 | */ | |
2289 | if (Sgl_iszero_exponentmantissa(opnd3)) { | |
2290 | if (Is_rounding_mode(ROUNDMINUS)) { | |
2291 | Sgl_or_signs(opnd3,resultp1); | |
2292 | } else { | |
2293 | Sgl_and_signs(opnd3,resultp1); | |
2294 | } | |
2295 | } | |
2296 | /* | |
2297 | * Now let's check for trapped underflow case. | |
2298 | */ | |
2299 | else if (Sgl_iszero_exponent(opnd3) && | |
2300 | Is_underflowtrap_enabled()) { | |
2301 | /* need to normalize results mantissa */ | |
2302 | sign_save = Sgl_signextendedsign(opnd3); | |
2303 | result_exponent = 0; | |
2304 | Sgl_leftshiftby1(opnd3); | |
2305 | Sgl_normalize(opnd3,result_exponent); | |
2306 | Sgl_set_sign(opnd3,/*using*/sign_save); | |
2307 | Sgl_setwrapped_exponent(opnd3,result_exponent, | |
2308 | unfl); | |
2309 | Sgl_copytoptr(opnd3,dstptr); | |
2310 | /* inexact = FALSE */ | |
2311 | return(OPC_2E_UNDERFLOWEXCEPTION); | |
2312 | } | |
2313 | Sgl_copytoptr(opnd3,dstptr); | |
2314 | return(NOEXCEPTION); | |
2315 | } | |
2316 | /* is denormalized; want to normalize */ | |
2317 | Sgl_clear_signexponent(opnd2); | |
2318 | Sgl_leftshiftby1(opnd2); | |
2319 | Sgl_normalize(opnd2,mpy_exponent); | |
2320 | } | |
2321 | ||
2322 | /* Multiply the first two source mantissas together */ | |
2323 | ||
2324 | /* | |
2325 | * The intermediate result will be kept in tmpres, | |
2326 | * which needs enough room for 106 bits of mantissa, | |
2327 | * so lets call it a Double extended. | |
2328 | */ | |
2329 | Sglext_setzero(tmpresp1,tmpresp2); | |
2330 | ||
2331 | /* | |
2332 | * Four bits at a time are inspected in each loop, and a | |
2333 | * simple shift and add multiply algorithm is used. | |
2334 | */ | |
2335 | for (count = SGL_P-1; count >= 0; count -= 4) { | |
2336 | Sglext_rightshiftby4(tmpresp1,tmpresp2); | |
2337 | if (Sbit28(opnd1)) { | |
2338 | /* Twoword_add should be an ADD followed by 2 ADDC's */ | |
2339 | Twoword_add(tmpresp1, tmpresp2, opnd2<<3, 0); | |
2340 | } | |
2341 | if (Sbit29(opnd1)) { | |
2342 | Twoword_add(tmpresp1, tmpresp2, opnd2<<2, 0); | |
2343 | } | |
2344 | if (Sbit30(opnd1)) { | |
2345 | Twoword_add(tmpresp1, tmpresp2, opnd2<<1, 0); | |
2346 | } | |
2347 | if (Sbit31(opnd1)) { | |
2348 | Twoword_add(tmpresp1, tmpresp2, opnd2, 0); | |
2349 | } | |
2350 | Sgl_rightshiftby4(opnd1); | |
2351 | } | |
2352 | if (Is_sexthiddenoverflow(tmpresp1)) { | |
2353 | /* result mantissa >= 2 (mantissa overflow) */ | |
2354 | mpy_exponent++; | |
2355 | Sglext_rightshiftby4(tmpresp1,tmpresp2); | |
2356 | } else { | |
2357 | Sglext_rightshiftby3(tmpresp1,tmpresp2); | |
2358 | } | |
2359 | ||
2360 | /* | |
2361 | * Restore the sign of the mpy result which was saved in resultp1. | |
2362 | * The exponent will continue to be kept in mpy_exponent. | |
2363 | */ | |
2364 | Sglext_set_sign(tmpresp1,Sgl_sign(resultp1)); | |
2365 | ||
2366 | /* | |
2367 | * No rounding is required, since the result of the multiply | |
2368 | * is exact in the extended format. | |
2369 | */ | |
2370 | ||
2371 | /* | |
2372 | * Now we are ready to perform the add portion of the operation. | |
2373 | * | |
2374 | * The exponents need to be kept as integers for now, since the | |
2375 | * multiply result might not fit into the exponent field. We | |
2376 | * can't overflow or underflow because of this yet, since the | |
2377 | * add could bring the final result back into range. | |
2378 | */ | |
2379 | add_exponent = Sgl_exponent(opnd3); | |
2380 | ||
2381 | /* | |
2382 | * Check for denormalized or zero add operand. | |
2383 | */ | |
2384 | if (add_exponent == 0) { | |
2385 | /* check for zero */ | |
2386 | if (Sgl_iszero_mantissa(opnd3)) { | |
2387 | /* right is zero */ | |
2388 | /* Left can't be zero and must be result. | |
2389 | * | |
2390 | * The final result is now in tmpres and mpy_exponent, | |
2391 | * and needs to be rounded and squeezed back into | |
2392 | * double precision format from double extended. | |
2393 | */ | |
2394 | result_exponent = mpy_exponent; | |
2395 | Sglext_copy(tmpresp1,tmpresp2,resultp1,resultp2); | |
2396 | sign_save = Sgl_signextendedsign(resultp1);/*save sign*/ | |
2397 | goto round; | |
2398 | } | |
2399 | ||
2400 | /* | |
2401 | * Neither are zeroes. | |
2402 | * Adjust exponent and normalize add operand. | |
2403 | */ | |
2404 | sign_save = Sgl_signextendedsign(opnd3); /* save sign */ | |
2405 | Sgl_clear_signexponent(opnd3); | |
2406 | Sgl_leftshiftby1(opnd3); | |
2407 | Sgl_normalize(opnd3,add_exponent); | |
2408 | Sgl_set_sign(opnd3,sign_save); /* restore sign */ | |
2409 | } else { | |
2410 | Sgl_clear_exponent_set_hidden(opnd3); | |
2411 | } | |
2412 | /* | |
2413 | * Copy opnd3 to the double extended variable called right. | |
2414 | */ | |
2415 | Sgl_copyto_sglext(opnd3,rightp1,rightp2); | |
2416 | ||
2417 | /* | |
2418 | * A zero "save" helps discover equal operands (for later), | |
2419 | * and is used in swapping operands (if needed). | |
2420 | */ | |
2421 | Sglext_xortointp1(tmpresp1,rightp1,/*to*/save); | |
2422 | ||
2423 | /* | |
2424 | * Compare magnitude of operands. | |
2425 | */ | |
2426 | Sglext_copytoint_exponentmantissa(tmpresp1,signlessleft1); | |
2427 | Sglext_copytoint_exponentmantissa(rightp1,signlessright1); | |
2428 | if (mpy_exponent < add_exponent || mpy_exponent == add_exponent && | |
2429 | Sglext_ismagnitudeless(signlessleft1,signlessright1)) { | |
2430 | /* | |
2431 | * Set the left operand to the larger one by XOR swap. | |
2432 | * First finish the first word "save". | |
2433 | */ | |
2434 | Sglext_xorfromintp1(save,rightp1,/*to*/rightp1); | |
2435 | Sglext_xorfromintp1(save,tmpresp1,/*to*/tmpresp1); | |
2436 | Sglext_swap_lower(tmpresp2,rightp2); | |
2437 | /* also setup exponents used in rest of routine */ | |
2438 | diff_exponent = add_exponent - mpy_exponent; | |
2439 | result_exponent = add_exponent; | |
2440 | } else { | |
2441 | /* also setup exponents used in rest of routine */ | |
2442 | diff_exponent = mpy_exponent - add_exponent; | |
2443 | result_exponent = mpy_exponent; | |
2444 | } | |
2445 | /* Invariant: left is not smaller than right. */ | |
2446 | ||
2447 | /* | |
2448 | * Special case alignment of operands that would force alignment | |
2449 | * beyond the extent of the extension. A further optimization | |
2450 | * could special case this but only reduces the path length for | |
2451 | * this infrequent case. | |
2452 | */ | |
2453 | if (diff_exponent > SGLEXT_THRESHOLD) { | |
2454 | diff_exponent = SGLEXT_THRESHOLD; | |
2455 | } | |
2456 | ||
2457 | /* Align right operand by shifting it to the right */ | |
2458 | Sglext_clear_sign(rightp1); | |
2459 | Sglext_right_align(rightp1,rightp2,/*shifted by*/diff_exponent); | |
2460 | ||
2461 | /* Treat sum and difference of the operands separately. */ | |
2462 | if ((int)save < 0) { | |
2463 | /* | |
2464 | * Difference of the two operands. Overflow can occur if the | |
2465 | * multiply overflowed. A borrow can occur out of the hidden | |
2466 | * bit and force a post normalization phase. | |
2467 | */ | |
2468 | Sglext_subtract(tmpresp1,tmpresp2, rightp1,rightp2, | |
2469 | resultp1,resultp2); | |
2470 | sign_save = Sgl_signextendedsign(resultp1); | |
2471 | if (Sgl_iszero_hidden(resultp1)) { | |
2472 | /* Handle normalization */ | |
25985edc | 2473 | /* A straightforward algorithm would now shift the |
1da177e4 LT |
2474 | * result and extension left until the hidden bit |
2475 | * becomes one. Not all of the extension bits need | |
2476 | * participate in the shift. Only the two most | |
2477 | * significant bits (round and guard) are needed. | |
2478 | * If only a single shift is needed then the guard | |
2479 | * bit becomes a significant low order bit and the | |
2480 | * extension must participate in the rounding. | |
2481 | * If more than a single shift is needed, then all | |
2482 | * bits to the right of the guard bit are zeros, | |
2483 | * and the guard bit may or may not be zero. */ | |
2484 | Sglext_leftshiftby1(resultp1,resultp2); | |
2485 | ||
2486 | /* Need to check for a zero result. The sign and | |
2487 | * exponent fields have already been zeroed. The more | |
2488 | * efficient test of the full object can be used. | |
2489 | */ | |
2490 | if (Sglext_iszero(resultp1,resultp2)) { | |
2491 | /* Must have been "x-x" or "x+(-x)". */ | |
2492 | if (Is_rounding_mode(ROUNDMINUS)) | |
2493 | Sgl_setone_sign(resultp1); | |
2494 | Sgl_copytoptr(resultp1,dstptr); | |
2495 | return(NOEXCEPTION); | |
2496 | } | |
2497 | result_exponent--; | |
2498 | ||
2499 | /* Look to see if normalization is finished. */ | |
2500 | if (Sgl_isone_hidden(resultp1)) { | |
2501 | /* No further normalization is needed */ | |
2502 | goto round; | |
2503 | } | |
2504 | ||
2505 | /* Discover first one bit to determine shift amount. | |
2506 | * Use a modified binary search. We have already | |
2507 | * shifted the result one position right and still | |
2508 | * not found a one so the remainder of the extension | |
2509 | * must be zero and simplifies rounding. */ | |
2510 | /* Scan bytes */ | |
2511 | while (Sgl_iszero_hiddenhigh7mantissa(resultp1)) { | |
2512 | Sglext_leftshiftby8(resultp1,resultp2); | |
2513 | result_exponent -= 8; | |
2514 | } | |
2515 | /* Now narrow it down to the nibble */ | |
2516 | if (Sgl_iszero_hiddenhigh3mantissa(resultp1)) { | |
2517 | /* The lower nibble contains the | |
2518 | * normalizing one */ | |
2519 | Sglext_leftshiftby4(resultp1,resultp2); | |
2520 | result_exponent -= 4; | |
2521 | } | |
2522 | /* Select case where first bit is set (already | |
2523 | * normalized) otherwise select the proper shift. */ | |
2524 | jumpsize = Sgl_hiddenhigh3mantissa(resultp1); | |
2525 | if (jumpsize <= 7) switch(jumpsize) { | |
2526 | case 1: | |
2527 | Sglext_leftshiftby3(resultp1,resultp2); | |
2528 | result_exponent -= 3; | |
2529 | break; | |
2530 | case 2: | |
2531 | case 3: | |
2532 | Sglext_leftshiftby2(resultp1,resultp2); | |
2533 | result_exponent -= 2; | |
2534 | break; | |
2535 | case 4: | |
2536 | case 5: | |
2537 | case 6: | |
2538 | case 7: | |
2539 | Sglext_leftshiftby1(resultp1,resultp2); | |
2540 | result_exponent -= 1; | |
2541 | break; | |
2542 | } | |
2543 | } /* end if (hidden...)... */ | |
2544 | /* Fall through and round */ | |
2545 | } /* end if (save < 0)... */ | |
2546 | else { | |
2547 | /* Add magnitudes */ | |
2548 | Sglext_addition(tmpresp1,tmpresp2, | |
2549 | rightp1,rightp2, /*to*/resultp1,resultp2); | |
2550 | sign_save = Sgl_signextendedsign(resultp1); | |
2551 | if (Sgl_isone_hiddenoverflow(resultp1)) { | |
2552 | /* Prenormalization required. */ | |
2553 | Sglext_arithrightshiftby1(resultp1,resultp2); | |
2554 | result_exponent++; | |
2555 | } /* end if hiddenoverflow... */ | |
2556 | } /* end else ...add magnitudes... */ | |
2557 | ||
2558 | /* Round the result. If the extension and lower two words are | |
2559 | * all zeros, then the result is exact. Otherwise round in the | |
2560 | * correct direction. Underflow is possible. If a postnormalization | |
2561 | * is necessary, then the mantissa is all zeros so no shift is needed. | |
2562 | */ | |
2563 | round: | |
2564 | if (result_exponent <= 0 && !Is_underflowtrap_enabled()) { | |
2565 | Sglext_denormalize(resultp1,resultp2,result_exponent,is_tiny); | |
2566 | } | |
2567 | Sgl_set_sign(resultp1,/*using*/sign_save); | |
2568 | if (Sglext_isnotzero_mantissap2(resultp2)) { | |
2569 | inexact = TRUE; | |
2570 | switch(Rounding_mode()) { | |
2571 | case ROUNDNEAREST: /* The default. */ | |
2572 | if (Sglext_isone_highp2(resultp2)) { | |
2573 | /* at least 1/2 ulp */ | |
2574 | if (Sglext_isnotzero_low31p2(resultp2) || | |
2575 | Sglext_isone_lowp1(resultp1)) { | |
2576 | /* either exactly half way and odd or | |
2577 | * more than 1/2ulp */ | |
2578 | Sgl_increment(resultp1); | |
2579 | } | |
2580 | } | |
2581 | break; | |
2582 | ||
2583 | case ROUNDPLUS: | |
2584 | if (Sgl_iszero_sign(resultp1)) { | |
2585 | /* Round up positive results */ | |
2586 | Sgl_increment(resultp1); | |
2587 | } | |
2588 | break; | |
2589 | ||
2590 | case ROUNDMINUS: | |
2591 | if (Sgl_isone_sign(resultp1)) { | |
2592 | /* Round down negative results */ | |
2593 | Sgl_increment(resultp1); | |
2594 | } | |
2595 | ||
2596 | case ROUNDZERO:; | |
2597 | /* truncate is simple */ | |
2598 | } /* end switch... */ | |
2599 | if (Sgl_isone_hiddenoverflow(resultp1)) result_exponent++; | |
2600 | } | |
2601 | if (result_exponent >= SGL_INFINITY_EXPONENT) { | |
2602 | /* Overflow */ | |
2603 | if (Is_overflowtrap_enabled()) { | |
2604 | /* | |
2605 | * Adjust bias of result | |
2606 | */ | |
2607 | Sgl_setwrapped_exponent(resultp1,result_exponent,ovfl); | |
2608 | Sgl_copytoptr(resultp1,dstptr); | |
2609 | if (inexact) | |
2610 | if (Is_inexacttrap_enabled()) | |
2611 | return (OPC_2E_OVERFLOWEXCEPTION | | |
2612 | OPC_2E_INEXACTEXCEPTION); | |
2613 | else Set_inexactflag(); | |
2614 | return (OPC_2E_OVERFLOWEXCEPTION); | |
2615 | } | |
2616 | inexact = TRUE; | |
2617 | Set_overflowflag(); | |
2618 | Sgl_setoverflow(resultp1); | |
2619 | } else if (result_exponent <= 0) { /* underflow case */ | |
2620 | if (Is_underflowtrap_enabled()) { | |
2621 | /* | |
2622 | * Adjust bias of result | |
2623 | */ | |
2624 | Sgl_setwrapped_exponent(resultp1,result_exponent,unfl); | |
2625 | Sgl_copytoptr(resultp1,dstptr); | |
2626 | if (inexact) | |
2627 | if (Is_inexacttrap_enabled()) | |
2628 | return (OPC_2E_UNDERFLOWEXCEPTION | | |
2629 | OPC_2E_INEXACTEXCEPTION); | |
2630 | else Set_inexactflag(); | |
2631 | return(OPC_2E_UNDERFLOWEXCEPTION); | |
2632 | } | |
2633 | else if (inexact && is_tiny) Set_underflowflag(); | |
2634 | } | |
2635 | else Sgl_set_exponent(resultp1,result_exponent); | |
2636 | Sgl_copytoptr(resultp1,dstptr); | |
2637 | if (inexact) | |
2638 | if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION); | |
2639 | else Set_inexactflag(); | |
2640 | return(NOEXCEPTION); | |
2641 | } | |
2642 |