kernel/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 }