KVM: emulator: emulate AAM
[linux-3.10.git] / arch / x86 / math-emu / reg_convert.c
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 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 }