You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
54 lines
1.6 KiB
54 lines
1.6 KiB
20 years ago
|
/*---------------------------------------------------------------------------+
|
||
|
|
| reg_convert.c |
|
||
|
|
| |
|
||
|
|
| Convert register representation. |
|
||
|
|
| |
|
||
|
|
| Copyright (C) 1992,1993,1994,1996,1997 |
|
||
|
|
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
|
||
|
|
| E-mail billm@suburbia.net |
|
||
|
|
| |
|
||
|
|
| |
|
||
|
|
+---------------------------------------------------------------------------*/
|
||
|
|
|
||
|
|
#include "exception.h"
|
||
|
|
#include "fpu_emu.h"
|
||
|
|
|
||
|
|
|
||
|
|
int FPU_to_exp16(FPU_REG const *a, FPU_REG *x)
|
||
|
|
{
|
||
|
|
int sign = getsign(a);
|
||
|
|
|
||
|
|
*(long long *)&(x->sigl) = *(const long long *)&(a->sigl);
|
||
|
|
|
||
|
|
/* Set up the exponent as a 16 bit quantity. */
|
||
|
|
setexponent16(x, exponent(a));
|
||
|
|
|
||
|
|
if ( exponent16(x) == EXP_UNDER )
|
||
|
|
{
|
||
|
|
/* The number is a de-normal or pseudodenormal. */
|
||
|
|
/* We only deal with the significand and exponent. */
|
||
|
|
|
||
|
|
if (x->sigh & 0x80000000)
|
||
|
|
{
|
||
|
|
/* Is a pseudodenormal. */
|
||
|
|
/* This is non-80486 behaviour because the number
|
||
|
|
loses its 'denormal' identity. */
|
||
|
|
addexponent(x, 1);
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
/* Is a denormal. */
|
||
|
|
addexponent(x, 1);
|
||
|
|
FPU_normalize_nuo(x);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if ( !(x->sigh & 0x80000000) )
|
||
|
|
{
|
||
|
|
EXCEPTION(EX_INTERNAL | 0x180);
|
||
|
|
}
|
||
|
|
|
||
|
|
return sign;
|
||
|
|
}
|
||
|
|
|