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
FPU_to_exp16(FPU_REG const * a,FPU_REG * x)16 int FPU_to_exp16(FPU_REG const *a, FPU_REG *x)
17 {
18 int sign = getsign(a);
19
20 *(long long *)&(x->sigl) = *(const long long *)&(a->sigl);
21
22 /* Set up the exponent as a 16 bit quantity. */
23 setexponent16(x, exponent(a));
24
25 if (exponent16(x) == EXP_UNDER) {
26 /* The number is a de-normal or pseudodenormal. */
27 /* We only deal with the significand and exponent. */
28
29 if (x->sigh & 0x80000000) {
30 /* Is a pseudodenormal. */
31 /* This is non-80486 behaviour because the number
32 loses its 'denormal' identity. */
33 addexponent(x, 1);
34 } else {
35 /* Is a denormal. */
36 addexponent(x, 1);
37 FPU_normalize_nuo(x);
38 }
39 }
40
41 if (!(x->sigh & 0x80000000)) {
42 EXCEPTION(EX_INTERNAL | 0x180);
43 }
44
45 return sign;
46 }
47