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252 lines
6.6 KiB
252 lines
6.6 KiB
// 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 <[email protected]> |
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*/ |
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#include "ieee754dp.h" |
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union ieee754dp ieee754dp_fmin(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 ? x : y; |
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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 ? y : x; |
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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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fallthrough; |
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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 x; |
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else if (xs < ys) |
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return y; |
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/* Signs of inputs are the same, 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 y; |
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else if (xe < ye) |
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return x; |
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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 x; |
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else if (xe < ye) |
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return y; |
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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 x; |
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return y; |
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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 y; |
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return x; |
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} |
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union ieee754dp ieee754dp_fmina(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 y; |
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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 x; |
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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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fallthrough; |
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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 y; |
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else if (xe < ye) |
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return x; |
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/* Compare mantissa */ |
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if (xm < ym) |
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return x; |
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else if (xm > ym) |
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return y; |
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else if (xs == 1) |
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return x; |
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return y; |
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}
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