150 lines
5.7 KiB
C
150 lines
5.7 KiB
C
/*============================================================================
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This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
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Package, Release 3e, by John R. Hauser.
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Copyright 2011, 2012, 2013, 2014, 2015, 2016 The Regents of the University of
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California. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright notice,
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this list of conditions, and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions, and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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3. Neither the name of the University nor the names of its contributors may
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be used to endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
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DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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=============================================================================*/
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#include <stdbool.h>
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#include <stdint.h>
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#include "internals.h"
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#include "specialize.h"
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#include "softfloat.h"
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#define SOFTFLOAT_FAST_DIV32TO16 1
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extern const uint16_t softfloat_approxRecip_1k0s[];
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extern const uint16_t softfloat_approxRecip_1k1s[];
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float16 f16_div(float16 a, float16 b, struct softfloat_status_t *status)
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{
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bool signA;
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int8_t expA;
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uint16_t sigA;
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bool signB;
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int8_t expB;
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uint16_t sigB;
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bool signZ;
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struct exp8_sig16 normExpSig;
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int8_t expZ;
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#ifdef SOFTFLOAT_FAST_DIV32TO16
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uint32_t sig32A;
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uint16_t sigZ;
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#endif
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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signA = signF16UI(a);
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expA = expF16UI(a);
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sigA = fracF16UI(a);
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signB = signF16UI(b);
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expB = expF16UI(b);
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sigB = fracF16UI(b);
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signZ = signA ^ signB;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if (softfloat_denormalsAreZeros(status)) {
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if (!expA) sigA = 0;
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if (!expB) sigB = 0;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if (expA == 0x1F) {
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if (sigA) goto propagateNaN;
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if (expB == 0x1F) {
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if (sigB) goto propagateNaN;
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goto invalid;
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}
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if (sigB && !expB)
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softfloat_raiseFlags(status, softfloat_flag_denormal);
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goto infinity;
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}
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if (expB == 0x1F) {
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if (sigB) goto propagateNaN;
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if (sigA && !expA)
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softfloat_raiseFlags(status, softfloat_flag_denormal);
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goto zero;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if (! expB) {
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if (! sigB) {
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if (! (expA | sigA)) goto invalid;
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softfloat_raiseFlags(status, softfloat_flag_infinite);
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goto infinity;
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}
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softfloat_raiseFlags(status, softfloat_flag_denormal);
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normExpSig = softfloat_normSubnormalF16Sig(sigB);
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expB = normExpSig.exp;
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sigB = normExpSig.sig;
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}
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if (! expA) {
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if (! sigA) goto zero;
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softfloat_raiseFlags(status, softfloat_flag_denormal);
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normExpSig = softfloat_normSubnormalF16Sig(sigA);
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expA = normExpSig.exp;
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sigA = normExpSig.sig;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expZ = expA - expB + 0xE;
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sigA |= 0x0400;
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sigB |= 0x0400;
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#ifdef SOFTFLOAT_FAST_DIV32TO16
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if (sigA < sigB) {
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--expZ;
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sig32A = (uint32_t) sigA<<15;
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} else {
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sig32A = (uint32_t) sigA<<14;
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}
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sigZ = sig32A / sigB;
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if (! (sigZ & 7)) sigZ |= ((uint32_t) sigB * sigZ != sig32A);
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#endif
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return softfloat_roundPackToF16(signZ, expZ, sigZ, status);
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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propagateNaN:
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return softfloat_propagateNaNF16UI(a, b, status);
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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invalid:
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softfloat_raiseFlags(status, softfloat_flag_invalid);
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return defaultNaNF16UI;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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infinity:
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return packToF16UI(signZ, 0x1F, 0);
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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zero:
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return packToF16UI(signZ, 0, 0);
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}
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