reg_convert.c

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