2019-05-31 15:09:55 +07:00
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// SPDX-License-Identifier: GPL-2.0-only
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2005-04-17 05:20:36 +07:00
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/* 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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#include "ieee754dp.h"
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2014-04-16 06:31:11 +07:00
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union ieee754dp ieee754dp_div(union ieee754dp x, union ieee754dp y)
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2005-04-17 05:20:36 +07:00
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{
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2014-04-26 06:49:14 +07:00
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u64 rm;
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int re;
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u64 bm;
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2005-04-17 05:20:36 +07:00
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COMPXDP;
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COMPYDP;
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EXPLODEXDP;
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EXPLODEYDP;
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2014-04-19 05:36:32 +07:00
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ieee754_clearcx();
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2005-04-17 05:20:36 +07:00
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FLUSHXDP;
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FLUSHYDP;
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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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2015-04-04 05:25:34 +07:00
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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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2005-04-17 05:20:36 +07:00
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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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2015-04-04 05:25:34 +07:00
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return ieee754dp_nanxcpt(x);
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2005-04-17 05:20:36 +07:00
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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 y;
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case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
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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 x;
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2014-04-26 06:49:14 +07:00
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/*
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* Infinity handling
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*/
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2005-04-17 05:20:36 +07:00
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case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
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2014-04-19 05:36:32 +07:00
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ieee754_setcx(IEEE754_INVALID_OPERATION);
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2014-04-25 08:19:57 +07:00
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return ieee754dp_indef();
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2005-04-17 05:20:36 +07:00
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case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
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return ieee754dp_zero(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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return ieee754dp_inf(xs ^ ys);
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2014-04-26 06:49:14 +07:00
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/*
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* Zero handling
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*/
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2005-04-17 05:20:36 +07:00
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case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
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2014-04-19 05:36:32 +07:00
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ieee754_setcx(IEEE754_INVALID_OPERATION);
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2014-04-25 08:19:57 +07:00
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return ieee754dp_indef();
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2005-04-17 05:20:36 +07:00
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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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2014-04-19 05:36:32 +07:00
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ieee754_setcx(IEEE754_ZERO_DIVIDE);
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2014-04-25 08:19:57 +07:00
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return ieee754dp_inf(xs ^ ys);
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2005-04-17 05:20:36 +07:00
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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 ieee754dp_zero(xs == ys ? 0 : 1);
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case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
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DPDNORMX;
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MIPS: math-emu: Mark fall throughs in switch statements with a comment
Mark intentional fall throughs in switch statements with a consistent
comment.
In most of the cases, a new comment line containing text "fall through"
is inserted. In some of the cases, existing comment contained a variation
of the text "fall through" (for example, "FALL THROUGH" or "drop through").
In such cases, the existing comment is modified to contain "fall through".
Lastly, in two cases, code segments were described in comments as "fall
througs", but were in reality "breaks out" of switch statement. In such
cases, existing comments are accordingly modified.
Apart from making code easier to follow and debug, this change enables
some static code analysers to interpret newly inserted comments as their
annotations (and, therefore, not issue warnings of type "fall through in
switch statement", which is desireable, since marked fallthroughs are
intentional).
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com>
Cc: Douglas Leung <douglas.leung@mips.com>
Cc: Goran Ferenc <goran.ferenc@mips.com>
Cc: James Hogan <james.hogan@mips.com>
Cc: Maciej W. Rozycki <macro@mips.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Cc: Miodrag Dinic <miodrag.dinic@mips.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Petar Jovanovic <petar.jovanovic@mips.com>
Cc: Raghu Gandham <raghu.gandham@mips.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17588/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-11-02 18:14:05 +07:00
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/* fall through */
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2005-04-17 05:20:36 +07:00
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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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break;
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case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
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break;
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}
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assert(xm & DP_HIDDEN_BIT);
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assert(ym & DP_HIDDEN_BIT);
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/* provide rounding space */
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xm <<= 3;
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ym <<= 3;
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2014-04-26 06:49:14 +07:00
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/* now the dirty work */
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2005-04-17 05:20:36 +07:00
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2014-04-26 06:49:14 +07:00
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rm = 0;
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re = xe - ye;
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2005-04-17 05:20:36 +07:00
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2014-04-26 06:49:14 +07:00
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for (bm = DP_MBIT(DP_FBITS + 2); bm; bm >>= 1) {
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if (xm >= ym) {
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xm -= ym;
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rm |= bm;
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if (xm == 0)
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break;
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2005-04-17 05:20:36 +07:00
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}
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2014-04-26 06:49:14 +07:00
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xm <<= 1;
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}
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rm <<= 1;
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if (xm)
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rm |= 1; /* have remainder, set sticky */
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2005-04-17 05:20:36 +07:00
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2014-04-26 06:49:14 +07:00
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assert(rm);
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/*
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* Normalise rm to rounding precision ?
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*/
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while ((rm >> (DP_FBITS + 3)) == 0) {
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rm <<= 1;
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re--;
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2005-04-17 05:20:36 +07:00
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}
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2014-04-26 06:49:14 +07:00
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return ieee754dp_format(xs == ys ? 0 : 1, re, rm);
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2005-04-17 05:20:36 +07:00
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}
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