mirror of https://gitee.com/openkylin/linux.git
74 lines
1.7 KiB
C
74 lines
1.7 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 "ieee754sp.h"
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#include "ieee754dp.h"
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union ieee754dp ieee754dp_fsp(union ieee754sp x)
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{
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COMPXSP;
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EXPLODEXSP;
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ieee754_clearcx();
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FLUSHXSP;
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switch (xc) {
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case IEEE754_CLASS_SNAN:
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ieee754_setcx(IEEE754_INVALID_OPERATION);
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return ieee754dp_nanxcpt(ieee754dp_indef());
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case IEEE754_CLASS_QNAN:
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return ieee754dp_nanxcpt(builddp(xs,
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DP_EMAX + 1 + DP_EBIAS,
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((u64) xm
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<< (DP_FBITS -
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SP_FBITS))));
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case IEEE754_CLASS_INF:
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return ieee754dp_inf(xs);
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case IEEE754_CLASS_ZERO:
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return ieee754dp_zero(xs);
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case IEEE754_CLASS_DNORM:
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/* normalize */
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while ((xm >> SP_FBITS) == 0) {
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xm <<= 1;
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xe--;
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}
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break;
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case IEEE754_CLASS_NORM:
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break;
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}
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/*
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* Can't possibly overflow,underflow, or need rounding
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*/
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/* drop the hidden bit */
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xm &= ~SP_HIDDEN_BIT;
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return builddp(xs, xe + DP_EBIAS,
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(u64) xm << (DP_FBITS - SP_FBITS));
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}
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