acrn-kernel/arch/i386/math-emu/reg_convert.c

54 lines
1.6 KiB
C

/*---------------------------------------------------------------------------+
| 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;
}