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/* IEEE754 floating point arithmetic
* double precision: common utilities
*/
/*
* MIPS floating point support
* Copyright (C) 1994-2000 Algorithmics Ltd.
* Copyright (C) 2017 Imagination Technologies, Ltd.
* Author: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
*
* This program is free software; you can distribute it and/or modify it
* under the terms of the GNU General Public License (Version 2) as
* published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program.
*/
#include "ieee754dp.h"
union ieee754dp ieee754dp_rint(union ieee754dp x)
{
union ieee754dp ret;
u64 residue;
int sticky;
int round;
int odd;
COMPXDP;
ieee754_clearcx();
EXPLODEXDP;
FLUSHXDP;
if (xc == IEEE754_CLASS_SNAN)
return ieee754dp_nanxcpt(x);
if ((xc == IEEE754_CLASS_QNAN) ||
(xc == IEEE754_CLASS_INF) ||
(xc == IEEE754_CLASS_ZERO))
return x;
if (xe >= DP_FBITS)
return x;
if (xe < -1) {
residue = xm;
round = 0;
sticky = residue != 0;
xm = 0;
} else {
residue = xm << (64 - DP_FBITS + xe);
round = (residue >> 63) != 0;
sticky = (residue << 1) != 0;
xm >>= DP_FBITS - xe;
}
odd = (xm & 0x1) != 0x0;
switch (ieee754_csr.rm) {
case FPU_CSR_RN: /* toward nearest */
if (round && (sticky || odd))
xm++;
break;
case FPU_CSR_RZ: /* toward zero */
break;
case FPU_CSR_RU: /* toward +infinity */
if ((round || sticky) && !xs)
xm++;
break;
case FPU_CSR_RD: /* toward -infinity */
if ((round || sticky) && xs)
xm++;
break;
}
if (round || sticky)
ieee754_setcx(IEEE754_INEXACT);
ret = ieee754dp_flong(xm);
DPSIGN(ret) = xs;
return ret;
}
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