Eyck Jentzsch
dcaf5467e8
(http://www.jhauser.us/arithmetic/SoftFloat.html) with RISCV specialization and cmake build
127 lines
4.7 KiB
C
127 lines
4.7 KiB
C
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/*============================================================================
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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 "platform.h"
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#include "internals.h"
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#include "specialize.h"
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float32_t softfloat_addMagsF32( uint_fast32_t uiA, uint_fast32_t uiB )
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{
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int_fast16_t expA;
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uint_fast32_t sigA;
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int_fast16_t expB;
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uint_fast32_t sigB;
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int_fast16_t expDiff;
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uint_fast32_t uiZ;
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bool signZ;
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int_fast16_t expZ;
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uint_fast32_t sigZ;
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union ui32_f32 uZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expA = expF32UI( uiA );
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sigA = fracF32UI( uiA );
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expB = expF32UI( uiB );
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sigB = fracF32UI( uiB );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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expDiff = expA - expB;
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if ( ! expDiff ) {
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/*--------------------------------------------------------------------
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*--------------------------------------------------------------------*/
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if ( ! expA ) {
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uiZ = uiA + sigB;
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goto uiZ;
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}
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if ( expA == 0xFF ) {
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if ( sigA | sigB ) goto propagateNaN;
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uiZ = uiA;
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goto uiZ;
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}
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signZ = signF32UI( uiA );
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expZ = expA;
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sigZ = 0x01000000 + sigA + sigB;
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if ( ! (sigZ & 1) && (expZ < 0xFE) ) {
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uiZ = packToF32UI( signZ, expZ, sigZ>>1 );
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goto uiZ;
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}
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sigZ <<= 6;
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} else {
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/*--------------------------------------------------------------------
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*--------------------------------------------------------------------*/
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signZ = signF32UI( uiA );
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sigA <<= 6;
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sigB <<= 6;
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if ( expDiff < 0 ) {
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if ( expB == 0xFF ) {
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if ( sigB ) goto propagateNaN;
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uiZ = packToF32UI( signZ, 0xFF, 0 );
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goto uiZ;
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}
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expZ = expB;
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sigA += expA ? 0x20000000 : sigA;
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sigA = softfloat_shiftRightJam32( sigA, -expDiff );
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} else {
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if ( expA == 0xFF ) {
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if ( sigA ) goto propagateNaN;
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uiZ = uiA;
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goto uiZ;
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}
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expZ = expA;
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sigB += expB ? 0x20000000 : sigB;
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sigB = softfloat_shiftRightJam32( sigB, expDiff );
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}
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sigZ = 0x20000000 + sigA + sigB;
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if ( sigZ < 0x40000000 ) {
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--expZ;
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sigZ <<= 1;
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}
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}
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return softfloat_roundPackToF32( signZ, expZ, sigZ );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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propagateNaN:
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uiZ = softfloat_propagateNaNF32UI( uiA, uiB );
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uiZ:
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uZ.ui = uiZ;
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return uZ.f;
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}
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