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9d5a634946
Based on 1 normalized pattern(s): this program is free software you can distribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 51 franklin st fifth floor boston ma 02110 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 33 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531081038.563233189@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
104 lines
1.8 KiB
C
104 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* IEEE754 floating point arithmetic
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* single precision square root
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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 "ieee754sp.h"
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union ieee754sp ieee754sp_sqrt(union ieee754sp x)
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{
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int ix, s, q, m, t, i;
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unsigned int r;
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COMPXSP;
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/* take care of Inf and NaN */
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EXPLODEXSP;
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ieee754_clearcx();
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FLUSHXSP;
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/* x == INF or NAN? */
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switch (xc) {
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case IEEE754_CLASS_SNAN:
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return ieee754sp_nanxcpt(x);
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case IEEE754_CLASS_QNAN:
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/* sqrt(Nan) = Nan */
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return x;
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case IEEE754_CLASS_ZERO:
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/* sqrt(0) = 0 */
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return x;
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case IEEE754_CLASS_INF:
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if (xs) {
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/* sqrt(-Inf) = Nan */
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ieee754_setcx(IEEE754_INVALID_OPERATION);
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return ieee754sp_indef();
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}
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/* sqrt(+Inf) = Inf */
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return x;
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case IEEE754_CLASS_DNORM:
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case IEEE754_CLASS_NORM:
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if (xs) {
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/* sqrt(-x) = Nan */
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ieee754_setcx(IEEE754_INVALID_OPERATION);
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return ieee754sp_indef();
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}
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break;
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}
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ix = x.bits;
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/* normalize x */
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m = (ix >> 23);
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if (m == 0) { /* subnormal x */
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for (i = 0; (ix & 0x00800000) == 0; i++)
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ix <<= 1;
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m -= i - 1;
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}
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m -= 127; /* unbias exponent */
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ix = (ix & 0x007fffff) | 0x00800000;
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if (m & 1) /* odd m, double x to make it even */
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ix += ix;
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m >>= 1; /* m = [m/2] */
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/* generate sqrt(x) bit by bit */
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ix += ix;
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s = 0;
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q = 0; /* q = sqrt(x) */
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r = 0x01000000; /* r = moving bit from right to left */
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while (r != 0) {
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t = s + r;
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if (t <= ix) {
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s = t + r;
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ix -= t;
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q += r;
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}
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ix += ix;
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r >>= 1;
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}
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if (ix != 0) {
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ieee754_setcx(IEEE754_INEXACT);
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switch (ieee754_csr.rm) {
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case FPU_CSR_RU:
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q += 2;
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break;
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case FPU_CSR_RN:
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q += (q & 1);
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break;
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}
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}
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ix = (q >> 1) + 0x3f000000;
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ix += (m << 23);
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x.bits = ix;
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return x;
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}
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