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1da177e4 LT |
1 | /*---------------------------------------------------------------------------+ |
2 | | reg_convert.c | | |
3 | | | | |
4 | | Convert register representation. | | |
5 | | | | |
6 | | Copyright (C) 1992,1993,1994,1996,1997 | | |
7 | | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia | | |
8 | | E-mail billm@suburbia.net | | |
9 | | | | |
10 | | | | |
11 | +---------------------------------------------------------------------------*/ | |
12 | ||
13 | #include "exception.h" | |
14 | #include "fpu_emu.h" | |
15 | ||
16 | ||
17 | int FPU_to_exp16(FPU_REG const *a, FPU_REG *x) | |
18 | { | |
19 | int sign = getsign(a); | |
20 | ||
21 | *(long long *)&(x->sigl) = *(const long long *)&(a->sigl); | |
22 | ||
23 | /* Set up the exponent as a 16 bit quantity. */ | |
24 | setexponent16(x, exponent(a)); | |
25 | ||
26 | if ( exponent16(x) == EXP_UNDER ) | |
27 | { | |
28 | /* The number is a de-normal or pseudodenormal. */ | |
29 | /* We only deal with the significand and exponent. */ | |
30 | ||
31 | if (x->sigh & 0x80000000) | |
32 | { | |
33 | /* Is a pseudodenormal. */ | |
34 | /* This is non-80486 behaviour because the number | |
35 | loses its 'denormal' identity. */ | |
36 | addexponent(x, 1); | |
37 | } | |
38 | else | |
39 | { | |
40 | /* Is a denormal. */ | |
41 | addexponent(x, 1); | |
42 | FPU_normalize_nuo(x); | |
43 | } | |
44 | } | |
45 | ||
46 | if ( !(x->sigh & 0x80000000) ) | |
47 | { | |
48 | EXCEPTION(EX_INTERNAL | 0x180); | |
49 | } | |
50 | ||
51 | return sign; | |
52 | } | |
53 |