66 строки
1.5 KiB
C
66 строки
1.5 KiB
C
/* IEEE754 floating point arithmetic
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* double precision: common utilities
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*/
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/*
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* MIPS floating point support
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* Copyright (C) 1994-2000 Algorithmics Ltd.
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*
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* This program is free software; you can distribute it and/or modify it
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* under the terms of the GNU General Public License (Version 2) as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "ieee754dp.h"
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union ieee754dp ieee754dp_flong(s64 x)
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{
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u64 xm;
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int xe;
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int xs;
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ieee754_clearcx();
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if (x == 0)
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return ieee754dp_zero(0);
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if (x == 1 || x == -1)
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return ieee754dp_one(x < 0);
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if (x == 10 || x == -10)
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return ieee754dp_ten(x < 0);
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xs = (x < 0);
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if (xs) {
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if (x == (1ULL << 63))
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xm = (1ULL << 63); /* max neg can't be safely negated */
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else
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xm = -x;
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} else {
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xm = x;
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}
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/* normalize */
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xe = DP_FBITS + 3;
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if (xm >> (DP_FBITS + 1 + 3)) {
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/* shunt out overflow bits */
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while (xm >> (DP_FBITS + 1 + 3)) {
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XDPSRSX1();
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}
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} else {
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/* normalize in grs extended double precision */
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while ((xm >> (DP_FBITS + 3)) == 0) {
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xm <<= 1;
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xe--;
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}
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}
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return ieee754dp_format(xs, xe, xm);
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}
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