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
FPU_to_exp16(FPU_REG const * a,FPU_REG * x)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
54