arch/i386/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
  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