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/* $NetBSD: fpu_int.c,v 1.1 1995/11/03 04:47:14 briggs Exp $ */
/*
* Copyright (c) 1995 Ken Nakata
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)fpu_int.c
*/
#include <sys/types.h>
#include <machine/reg.h>
#include "fpu_arith.h"
#include "fpu_emulate.h"
/* FINTRZ - always round to zero */
struct fpn *
fpu_intrz(fe)
struct fpemu *fe;
{
register struct fpn *x = &fe->fe_f2;
register int sh, clr, mask, i;
/* special cases first */
if (x->fp_class != FPC_NUM) {
return x;
}
/* when |x| < 1.0 */
if (x->fp_exp < 0) {
x->fp_class = FPC_ZERO;
x->fp_mant[0] = x->fp_mant[1] = x->fp_mant[2] = x->fp_mant[3] = 0;
return x;
}
/* real work */
sh = FP_NMANT - 1 - x->fp_exp;
if (sh <= 0) {
return x;
}
clr = 3 - sh / 32;
mask = (0xffffffff << (sh % 32));
for (i = 3; i > clr; i--) {
x->fp_mant[i] = 0;
}
x->fp_mant[i] &= mask;
return x;
}
/* FINT */
struct fpn *
fpu_int(fe)
struct fpemu *fe;
{
register struct fpn *x = &fe->fe_f2;
register int rsh, lsh, wsh, i;
/* special cases first */
if (x->fp_class != FPC_NUM) {
return x;
}
/* even if we have exponent == -1, we still have possiblity
that the result >= 1.0 when mantissa ~= 1.0 and rounded up */
if (x->fp_exp < -1) {
x->fp_class = FPC_ZERO;
x->fp_mant[0] = x->fp_mant[1] = x->fp_mant[2] = x->fp_mant[3] = 0;
return x;
}
/* real work */
rsh = FP_NMANT - 1 - x->fp_exp;
if (rsh - FP_NG <= 0) {
return x;
}
fpu_shr(x, rsh - FP_NG); /* shift to the right */
if (round(fe, x) == 1 /* rounded up */ &&
x->fp_mant[3 - (FP_NMANT-rsh)/32] & (1 << ((FP_NMANT-rsh)%32))
/* x >= 2.0 */) {
rsh--; /* reduce shift count by 1 */
x->fp_exp++; /* adjust exponent */
}
/* shift it back to the left */
wsh = rsh / 32;
lsh = rsh % 32;
rsh = 32 - lsh;
for (i = 0; i + wsh < 3; i++) {
x->fp_mant[i] = (x->fp_mant[i+wsh] << lsh) | (x->fp_mant[i+wsh+1] >> rsh);
}
x->fp_mant[i++] = (x->fp_mant[i+wsh] << lsh);
for (; i < 4; i++) {
x->fp_mant[i] = 0;
}
return x;
}
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