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74ba9207 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | NetWinder Floating Point Emulator | |
4 | (c) Rebel.COM, 1998,1999 | |
5 | (c) Philip Blundell, 1999, 2001 | |
6 | ||
7 | Direct questions, comments to Scott Bambrough <scottb@netwinder.org> | |
8 | ||
1da177e4 LT |
9 | */ |
10 | ||
1da177e4 LT |
11 | #include "fpa11.h" |
12 | #include "fpopcode.h" | |
13 | #include "fpa11.inl" | |
14 | #include "fpmodule.h" | |
15 | #include "fpmodule.inl" | |
6ec5e7f3 | 16 | #include "softfloat.h" |
1da177e4 | 17 | |
1da177e4 LT |
18 | unsigned int PerformFLT(const unsigned int opcode); |
19 | unsigned int PerformFIX(const unsigned int opcode); | |
20 | ||
21 | static unsigned int PerformComparison(const unsigned int opcode); | |
22 | ||
23 | unsigned int EmulateCPRT(const unsigned int opcode) | |
24 | { | |
25 | ||
26 | if (opcode & 0x800000) { | |
27 | /* This is some variant of a comparison (PerformComparison | |
28 | will sort out which one). Since most of the other CPRT | |
29 | instructions are oddball cases of some sort or other it | |
30 | makes sense to pull this out into a fast path. */ | |
31 | return PerformComparison(opcode); | |
32 | } | |
33 | ||
34 | /* Hint to GCC that we'd like a jump table rather than a load of CMPs */ | |
35 | switch ((opcode & 0x700000) >> 20) { | |
36 | case FLT_CODE >> 20: | |
37 | return PerformFLT(opcode); | |
38 | break; | |
39 | case FIX_CODE >> 20: | |
40 | return PerformFIX(opcode); | |
41 | break; | |
42 | ||
43 | case WFS_CODE >> 20: | |
44 | writeFPSR(readRegister(getRd(opcode))); | |
45 | break; | |
46 | case RFS_CODE >> 20: | |
47 | writeRegister(getRd(opcode), readFPSR()); | |
48 | break; | |
49 | ||
50 | default: | |
51 | return 0; | |
52 | } | |
53 | ||
54 | return 1; | |
55 | } | |
56 | ||
57 | unsigned int PerformFLT(const unsigned int opcode) | |
58 | { | |
59 | FPA11 *fpa11 = GET_FPA11(); | |
f148af25 RP |
60 | struct roundingData roundData; |
61 | ||
62 | roundData.mode = SetRoundingMode(opcode); | |
63 | roundData.precision = SetRoundingPrecision(opcode); | |
64 | roundData.exception = 0; | |
1da177e4 LT |
65 | |
66 | switch (opcode & MASK_ROUNDING_PRECISION) { | |
67 | case ROUND_SINGLE: | |
68 | { | |
69 | fpa11->fType[getFn(opcode)] = typeSingle; | |
f148af25 | 70 | fpa11->fpreg[getFn(opcode)].fSingle = int32_to_float32(&roundData, readRegister(getRd(opcode))); |
1da177e4 LT |
71 | } |
72 | break; | |
73 | ||
74 | case ROUND_DOUBLE: | |
75 | { | |
76 | fpa11->fType[getFn(opcode)] = typeDouble; | |
77 | fpa11->fpreg[getFn(opcode)].fDouble = int32_to_float64(readRegister(getRd(opcode))); | |
78 | } | |
79 | break; | |
80 | ||
81 | #ifdef CONFIG_FPE_NWFPE_XP | |
82 | case ROUND_EXTENDED: | |
83 | { | |
84 | fpa11->fType[getFn(opcode)] = typeExtended; | |
85 | fpa11->fpreg[getFn(opcode)].fExtended = int32_to_floatx80(readRegister(getRd(opcode))); | |
86 | } | |
87 | break; | |
88 | #endif | |
89 | ||
90 | default: | |
91 | return 0; | |
92 | } | |
93 | ||
f148af25 RP |
94 | if (roundData.exception) |
95 | float_raise(roundData.exception); | |
96 | ||
1da177e4 LT |
97 | return 1; |
98 | } | |
99 | ||
100 | unsigned int PerformFIX(const unsigned int opcode) | |
101 | { | |
102 | FPA11 *fpa11 = GET_FPA11(); | |
103 | unsigned int Fn = getFm(opcode); | |
f148af25 | 104 | struct roundingData roundData; |
1da177e4 | 105 | |
f148af25 RP |
106 | roundData.mode = SetRoundingMode(opcode); |
107 | roundData.precision = SetRoundingPrecision(opcode); | |
108 | roundData.exception = 0; | |
1da177e4 LT |
109 | |
110 | switch (fpa11->fType[Fn]) { | |
111 | case typeSingle: | |
112 | { | |
f148af25 | 113 | writeRegister(getRd(opcode), float32_to_int32(&roundData, fpa11->fpreg[Fn].fSingle)); |
1da177e4 LT |
114 | } |
115 | break; | |
116 | ||
117 | case typeDouble: | |
118 | { | |
f148af25 | 119 | writeRegister(getRd(opcode), float64_to_int32(&roundData, fpa11->fpreg[Fn].fDouble)); |
1da177e4 LT |
120 | } |
121 | break; | |
122 | ||
123 | #ifdef CONFIG_FPE_NWFPE_XP | |
124 | case typeExtended: | |
125 | { | |
f148af25 | 126 | writeRegister(getRd(opcode), floatx80_to_int32(&roundData, fpa11->fpreg[Fn].fExtended)); |
1da177e4 LT |
127 | } |
128 | break; | |
129 | #endif | |
130 | ||
131 | default: | |
132 | return 0; | |
133 | } | |
134 | ||
f148af25 RP |
135 | if (roundData.exception) |
136 | float_raise(roundData.exception); | |
137 | ||
1da177e4 LT |
138 | return 1; |
139 | } | |
140 | ||
141 | /* This instruction sets the flags N, Z, C, V in the FPSR. */ | |
142 | static unsigned int PerformComparison(const unsigned int opcode) | |
143 | { | |
144 | FPA11 *fpa11 = GET_FPA11(); | |
145 | unsigned int Fn = getFn(opcode), Fm = getFm(opcode); | |
146 | int e_flag = opcode & 0x400000; /* 1 if CxFE */ | |
147 | int n_flag = opcode & 0x200000; /* 1 if CNxx */ | |
148 | unsigned int flags = 0; | |
149 | ||
150 | #ifdef CONFIG_FPE_NWFPE_XP | |
151 | floatx80 rFn, rFm; | |
152 | ||
153 | /* Check for unordered condition and convert all operands to 80-bit | |
154 | format. | |
155 | ?? Might be some mileage in avoiding this conversion if possible. | |
156 | Eg, if both operands are 32-bit, detect this and do a 32-bit | |
157 | comparison (cheaper than an 80-bit one). */ | |
158 | switch (fpa11->fType[Fn]) { | |
159 | case typeSingle: | |
160 | //printk("single.\n"); | |
161 | if (float32_is_nan(fpa11->fpreg[Fn].fSingle)) | |
162 | goto unordered; | |
163 | rFn = float32_to_floatx80(fpa11->fpreg[Fn].fSingle); | |
164 | break; | |
165 | ||
166 | case typeDouble: | |
167 | //printk("double.\n"); | |
168 | if (float64_is_nan(fpa11->fpreg[Fn].fDouble)) | |
169 | goto unordered; | |
170 | rFn = float64_to_floatx80(fpa11->fpreg[Fn].fDouble); | |
171 | break; | |
172 | ||
173 | case typeExtended: | |
174 | //printk("extended.\n"); | |
175 | if (floatx80_is_nan(fpa11->fpreg[Fn].fExtended)) | |
176 | goto unordered; | |
177 | rFn = fpa11->fpreg[Fn].fExtended; | |
178 | break; | |
179 | ||
180 | default: | |
181 | return 0; | |
182 | } | |
183 | ||
184 | if (CONSTANT_FM(opcode)) { | |
185 | //printk("Fm is a constant: #%d.\n",Fm); | |
186 | rFm = getExtendedConstant(Fm); | |
187 | if (floatx80_is_nan(rFm)) | |
188 | goto unordered; | |
189 | } else { | |
190 | //printk("Fm = r%d which contains a ",Fm); | |
191 | switch (fpa11->fType[Fm]) { | |
192 | case typeSingle: | |
193 | //printk("single.\n"); | |
194 | if (float32_is_nan(fpa11->fpreg[Fm].fSingle)) | |
195 | goto unordered; | |
196 | rFm = float32_to_floatx80(fpa11->fpreg[Fm].fSingle); | |
197 | break; | |
198 | ||
199 | case typeDouble: | |
200 | //printk("double.\n"); | |
201 | if (float64_is_nan(fpa11->fpreg[Fm].fDouble)) | |
202 | goto unordered; | |
203 | rFm = float64_to_floatx80(fpa11->fpreg[Fm].fDouble); | |
204 | break; | |
205 | ||
206 | case typeExtended: | |
207 | //printk("extended.\n"); | |
208 | if (floatx80_is_nan(fpa11->fpreg[Fm].fExtended)) | |
209 | goto unordered; | |
210 | rFm = fpa11->fpreg[Fm].fExtended; | |
211 | break; | |
212 | ||
213 | default: | |
214 | return 0; | |
215 | } | |
216 | } | |
217 | ||
218 | if (n_flag) | |
219 | rFm.high ^= 0x8000; | |
220 | ||
221 | /* test for less than condition */ | |
222 | if (floatx80_lt(rFn, rFm)) | |
223 | flags |= CC_NEGATIVE; | |
224 | ||
225 | /* test for equal condition */ | |
226 | if (floatx80_eq(rFn, rFm)) | |
227 | flags |= CC_ZERO; | |
228 | ||
229 | /* test for greater than or equal condition */ | |
230 | if (floatx80_lt(rFm, rFn)) | |
231 | flags |= CC_CARRY; | |
232 | ||
233 | #else | |
234 | if (CONSTANT_FM(opcode)) { | |
235 | /* Fm is a constant. Do the comparison in whatever precision | |
236 | Fn happens to be stored in. */ | |
237 | if (fpa11->fType[Fn] == typeSingle) { | |
238 | float32 rFm = getSingleConstant(Fm); | |
239 | float32 rFn = fpa11->fpreg[Fn].fSingle; | |
240 | ||
241 | if (float32_is_nan(rFn)) | |
242 | goto unordered; | |
243 | ||
244 | if (n_flag) | |
245 | rFm ^= 0x80000000; | |
246 | ||
247 | /* test for less than condition */ | |
248 | if (float32_lt_nocheck(rFn, rFm)) | |
249 | flags |= CC_NEGATIVE; | |
250 | ||
251 | /* test for equal condition */ | |
252 | if (float32_eq_nocheck(rFn, rFm)) | |
253 | flags |= CC_ZERO; | |
254 | ||
255 | /* test for greater than or equal condition */ | |
256 | if (float32_lt_nocheck(rFm, rFn)) | |
257 | flags |= CC_CARRY; | |
258 | } else { | |
259 | float64 rFm = getDoubleConstant(Fm); | |
260 | float64 rFn = fpa11->fpreg[Fn].fDouble; | |
261 | ||
262 | if (float64_is_nan(rFn)) | |
263 | goto unordered; | |
264 | ||
265 | if (n_flag) | |
266 | rFm ^= 0x8000000000000000ULL; | |
267 | ||
268 | /* test for less than condition */ | |
269 | if (float64_lt_nocheck(rFn, rFm)) | |
270 | flags |= CC_NEGATIVE; | |
271 | ||
272 | /* test for equal condition */ | |
273 | if (float64_eq_nocheck(rFn, rFm)) | |
274 | flags |= CC_ZERO; | |
275 | ||
276 | /* test for greater than or equal condition */ | |
277 | if (float64_lt_nocheck(rFm, rFn)) | |
278 | flags |= CC_CARRY; | |
279 | } | |
280 | } else { | |
281 | /* Both operands are in registers. */ | |
282 | if (fpa11->fType[Fn] == typeSingle | |
283 | && fpa11->fType[Fm] == typeSingle) { | |
284 | float32 rFm = fpa11->fpreg[Fm].fSingle; | |
285 | float32 rFn = fpa11->fpreg[Fn].fSingle; | |
286 | ||
287 | if (float32_is_nan(rFn) | |
288 | || float32_is_nan(rFm)) | |
289 | goto unordered; | |
290 | ||
291 | if (n_flag) | |
292 | rFm ^= 0x80000000; | |
293 | ||
294 | /* test for less than condition */ | |
295 | if (float32_lt_nocheck(rFn, rFm)) | |
296 | flags |= CC_NEGATIVE; | |
297 | ||
298 | /* test for equal condition */ | |
299 | if (float32_eq_nocheck(rFn, rFm)) | |
300 | flags |= CC_ZERO; | |
301 | ||
302 | /* test for greater than or equal condition */ | |
303 | if (float32_lt_nocheck(rFm, rFn)) | |
304 | flags |= CC_CARRY; | |
305 | } else { | |
306 | /* Promote 32-bit operand to 64 bits. */ | |
307 | float64 rFm, rFn; | |
308 | ||
309 | rFm = (fpa11->fType[Fm] == typeSingle) ? | |
310 | float32_to_float64(fpa11->fpreg[Fm].fSingle) | |
311 | : fpa11->fpreg[Fm].fDouble; | |
312 | ||
313 | rFn = (fpa11->fType[Fn] == typeSingle) ? | |
314 | float32_to_float64(fpa11->fpreg[Fn].fSingle) | |
315 | : fpa11->fpreg[Fn].fDouble; | |
316 | ||
317 | if (float64_is_nan(rFn) | |
318 | || float64_is_nan(rFm)) | |
319 | goto unordered; | |
320 | ||
321 | if (n_flag) | |
322 | rFm ^= 0x8000000000000000ULL; | |
323 | ||
324 | /* test for less than condition */ | |
325 | if (float64_lt_nocheck(rFn, rFm)) | |
326 | flags |= CC_NEGATIVE; | |
327 | ||
328 | /* test for equal condition */ | |
329 | if (float64_eq_nocheck(rFn, rFm)) | |
330 | flags |= CC_ZERO; | |
331 | ||
332 | /* test for greater than or equal condition */ | |
333 | if (float64_lt_nocheck(rFm, rFn)) | |
334 | flags |= CC_CARRY; | |
335 | } | |
336 | } | |
337 | ||
338 | #endif | |
339 | ||
340 | writeConditionCodes(flags); | |
341 | ||
342 | return 1; | |
343 | ||
344 | unordered: | |
345 | /* ?? The FPA data sheet is pretty vague about this, in particular | |
346 | about whether the non-E comparisons can ever raise exceptions. | |
347 | This implementation is based on a combination of what it says in | |
348 | the data sheet, observation of how the Acorn emulator actually | |
349 | behaves (and how programs expect it to) and guesswork. */ | |
350 | flags |= CC_OVERFLOW; | |
351 | flags &= ~(CC_ZERO | CC_NEGATIVE); | |
352 | ||
353 | if (BIT_AC & readFPSR()) | |
354 | flags |= CC_CARRY; | |
355 | ||
356 | if (e_flag) | |
357 | float_raise(float_flag_invalid); | |
358 | ||
359 | writeConditionCodes(flags); | |
360 | return 1; | |
361 | } |