mirror of https://gitee.com/openkylin/linux.git
255 lines
6.6 KiB
C
255 lines
6.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* IEEE754 floating point arithmetic
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* double precision: MIN{,A}.f
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* MIN : Scalar Floating-Point Minimum
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* MINA: Scalar Floating-Point argument with Minimum Absolute Value
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*
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* MIN.D : FPR[fd] = minNum(FPR[fs],FPR[ft])
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* MINA.D: FPR[fd] = maxNumMag(FPR[fs],FPR[ft])
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*
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* MIPS floating point support
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* Copyright (C) 2015 Imagination Technologies, Ltd.
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* Author: Markos Chandras <markos.chandras@imgtec.com>
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*/
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#include "ieee754dp.h"
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union ieee754dp ieee754dp_fmax(union ieee754dp x, union ieee754dp y)
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{
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COMPXDP;
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COMPYDP;
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EXPLODEXDP;
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EXPLODEYDP;
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FLUSHXDP;
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FLUSHYDP;
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ieee754_clearcx();
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switch (CLPAIR(xc, yc)) {
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
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case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
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return ieee754dp_nanxcpt(y);
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case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
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case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
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case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
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case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
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case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
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case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
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return ieee754dp_nanxcpt(x);
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/*
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* Quiet NaN handling
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*/
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/*
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* The case of both inputs quiet NaNs
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*/
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
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return x;
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/*
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* The cases of exactly one input quiet NaN (numbers
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* are here preferred as returned values to NaNs)
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*/
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
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case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
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return x;
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
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return y;
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/*
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* Infinity and zero handling
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*/
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
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case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
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return xs ? y : x;
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
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case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
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return ys ? x : y;
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
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return ieee754dp_zero(xs & ys);
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
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DPDNORMX;
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/* fall through */
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case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
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DPDNORMY;
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break;
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
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DPDNORMX;
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}
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/* Finally get to do some computation */
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assert(xm & DP_HIDDEN_BIT);
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assert(ym & DP_HIDDEN_BIT);
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/* Compare signs */
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if (xs > ys)
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return y;
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else if (xs < ys)
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return x;
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/* Signs of inputs are equal, let's compare exponents */
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if (xs == 0) {
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/* Inputs are both positive */
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if (xe > ye)
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return x;
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else if (xe < ye)
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return y;
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} else {
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/* Inputs are both negative */
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if (xe > ye)
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return y;
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else if (xe < ye)
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return x;
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}
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/* Signs and exponents of inputs are equal, let's compare mantissas */
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if (xs == 0) {
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/* Inputs are both positive, with equal signs and exponents */
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if (xm <= ym)
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return y;
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return x;
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}
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/* Inputs are both negative, with equal signs and exponents */
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if (xm <= ym)
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return x;
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return y;
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}
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union ieee754dp ieee754dp_fmaxa(union ieee754dp x, union ieee754dp y)
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{
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COMPXDP;
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COMPYDP;
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EXPLODEXDP;
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EXPLODEYDP;
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FLUSHXDP;
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FLUSHYDP;
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ieee754_clearcx();
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switch (CLPAIR(xc, yc)) {
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
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case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
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return ieee754dp_nanxcpt(y);
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case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
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case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
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case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
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case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
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case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
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case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
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return ieee754dp_nanxcpt(x);
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/*
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* Quiet NaN handling
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*/
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/*
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* The case of both inputs quiet NaNs
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*/
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
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return x;
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/*
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* The cases of exactly one input quiet NaN (numbers
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* are here preferred as returned values to NaNs)
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*/
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
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case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
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return x;
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
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return y;
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/*
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* Infinity and zero handling
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*/
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
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return ieee754dp_inf(xs & ys);
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
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case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
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return x;
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case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
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return y;
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
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return ieee754dp_zero(xs & ys);
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
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DPDNORMX;
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/* fall through */
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case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
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DPDNORMY;
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break;
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
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DPDNORMX;
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}
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/* Finally get to do some computation */
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assert(xm & DP_HIDDEN_BIT);
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assert(ym & DP_HIDDEN_BIT);
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/* Compare exponent */
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if (xe > ye)
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return x;
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else if (xe < ye)
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return y;
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/* Compare mantissa */
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if (xm < ym)
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return y;
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else if (xm > ym)
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return x;
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else if (xs == 0)
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return x;
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return y;
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}
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