| |
| /*============================================================================ |
| |
| This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic |
| Package, Release 3d, by John R. Hauser. |
| |
| Copyright 2011, 2012, 2013, 2014, 2015, 2016 The Regents of the University of |
| California. All rights reserved. |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions are met: |
| |
| 1. Redistributions of source code must retain the above copyright notice, |
| this list of conditions, and the following disclaimer. |
| |
| 2. Redistributions in binary form must reproduce the above copyright notice, |
| this list of conditions, and the following disclaimer in the documentation |
| and/or other materials provided with the distribution. |
| |
| 3. Neither the name of the University nor the names of its contributors may |
| be used to endorse or promote products derived from this software without |
| specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY |
| EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE |
| DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY |
| DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| =============================================================================*/ |
| |
| #include <stdbool.h> |
| #include <stdint.h> |
| #include "platform.h" |
| #include "internals.h" |
| #include "specialize.h" |
| #include "softfloat.h" |
| |
| float16_t |
| softfloat_mulAddF16( |
| uint_fast16_t uiA, uint_fast16_t uiB, uint_fast16_t uiC, uint_fast8_t op ) |
| { |
| bool signA; |
| int_fast8_t expA; |
| uint_fast16_t sigA; |
| bool signB; |
| int_fast8_t expB; |
| uint_fast16_t sigB; |
| bool signC; |
| int_fast8_t expC; |
| uint_fast16_t sigC; |
| bool signProd; |
| uint_fast16_t magBits, uiZ; |
| struct exp8_sig16 normExpSig; |
| int_fast8_t expProd; |
| uint_fast32_t sigProd; |
| bool signZ; |
| int_fast8_t expZ; |
| uint_fast16_t sigZ; |
| int_fast8_t expDiff; |
| uint_fast32_t sig32Z, sig32C; |
| int_fast8_t shiftDist; |
| union ui16_f16 uZ; |
| |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| signA = signF16UI( uiA ); |
| expA = expF16UI( uiA ); |
| sigA = fracF16UI( uiA ); |
| signB = signF16UI( uiB ); |
| expB = expF16UI( uiB ); |
| sigB = fracF16UI( uiB ); |
| signC = signF16UI( uiC ) ^ (op == softfloat_mulAdd_subC); |
| expC = expF16UI( uiC ); |
| sigC = fracF16UI( uiC ); |
| signProd = signA ^ signB ^ (op == softfloat_mulAdd_subProd); |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| if ( expA == 0x1F ) { |
| if ( sigA || ((expB == 0x1F) && sigB) ) goto propagateNaN_ABC; |
| magBits = expB | sigB; |
| goto infProdArg; |
| } |
| if ( expB == 0x1F ) { |
| if ( sigB ) goto propagateNaN_ABC; |
| magBits = expA | sigA; |
| goto infProdArg; |
| } |
| if ( expC == 0x1F ) { |
| if ( sigC ) { |
| uiZ = 0; |
| goto propagateNaN_ZC; |
| } |
| uiZ = uiC; |
| goto uiZ; |
| } |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| if ( ! expA ) { |
| if ( ! sigA ) goto zeroProd; |
| normExpSig = softfloat_normSubnormalF16Sig( sigA ); |
| expA = normExpSig.exp; |
| sigA = normExpSig.sig; |
| } |
| if ( ! expB ) { |
| if ( ! sigB ) goto zeroProd; |
| normExpSig = softfloat_normSubnormalF16Sig( sigB ); |
| expB = normExpSig.exp; |
| sigB = normExpSig.sig; |
| } |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| expProd = expA + expB - 0xE; |
| sigA = (sigA | 0x0400)<<4; |
| sigB = (sigB | 0x0400)<<4; |
| sigProd = (uint_fast32_t) sigA * sigB; |
| if ( sigProd < 0x20000000 ) { |
| --expProd; |
| sigProd <<= 1; |
| } |
| signZ = signProd; |
| if ( ! expC ) { |
| if ( ! sigC ) { |
| expZ = expProd - 1; |
| sigZ = sigProd>>15 | ((sigProd & 0x7FFF) != 0); |
| goto roundPack; |
| } |
| normExpSig = softfloat_normSubnormalF16Sig( sigC ); |
| expC = normExpSig.exp; |
| sigC = normExpSig.sig; |
| } |
| sigC = (sigC | 0x0400)<<3; |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| expDiff = expProd - expC; |
| if ( signProd == signC ) { |
| /*-------------------------------------------------------------------- |
| *--------------------------------------------------------------------*/ |
| if ( expDiff <= 0 ) { |
| expZ = expC; |
| sigZ = sigC + softfloat_shiftRightJam32( sigProd, 16 - expDiff ); |
| } else { |
| expZ = expProd; |
| sig32Z = |
| sigProd |
| + softfloat_shiftRightJam32( |
| (uint_fast32_t) sigC<<16, expDiff ); |
| sigZ = sig32Z>>16 | ((sig32Z & 0xFFFF) != 0 ); |
| } |
| if ( sigZ < 0x4000 ) { |
| --expZ; |
| sigZ <<= 1; |
| } |
| } else { |
| /*-------------------------------------------------------------------- |
| *--------------------------------------------------------------------*/ |
| sig32C = (uint_fast32_t) sigC<<16; |
| if ( expDiff < 0 ) { |
| signZ = signC; |
| expZ = expC; |
| sig32Z = sig32C - softfloat_shiftRightJam32( sigProd, -expDiff ); |
| } else if ( ! expDiff ) { |
| expZ = expProd; |
| sig32Z = sigProd - sig32C; |
| if ( ! sig32Z ) goto completeCancellation; |
| if ( sig32Z & 0x80000000 ) { |
| signZ = ! signZ; |
| sig32Z = -sig32Z; |
| } |
| } else { |
| expZ = expProd; |
| sig32Z = sigProd - softfloat_shiftRightJam32( sig32C, expDiff ); |
| } |
| shiftDist = softfloat_countLeadingZeros32( sig32Z ) - 1; |
| expZ -= shiftDist; |
| shiftDist -= 16; |
| if ( shiftDist < 0 ) { |
| sigZ = |
| sig32Z>>(-shiftDist) |
| | ((uint32_t) (sig32Z<<(shiftDist & 31)) != 0); |
| } else { |
| sigZ = (uint_fast16_t) sig32Z<<shiftDist; |
| } |
| } |
| roundPack: |
| return softfloat_roundPackToF16( signZ, expZ, sigZ ); |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| propagateNaN_ABC: |
| uiZ = softfloat_propagateNaNF16UI( uiA, uiB ); |
| goto propagateNaN_ZC; |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| infProdArg: |
| if ( magBits ) { |
| uiZ = packToF16UI( signProd, 0x1F, 0 ); |
| if ( expC != 0x1F ) goto uiZ; |
| if ( sigC ) goto propagateNaN_ZC; |
| if ( signProd == signC ) goto uiZ; |
| } |
| softfloat_raiseFlags( softfloat_flag_invalid ); |
| uiZ = defaultNaNF16UI; |
| propagateNaN_ZC: |
| uiZ = softfloat_propagateNaNF16UI( uiZ, uiC ); |
| goto uiZ; |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| zeroProd: |
| uiZ = uiC; |
| if ( ! (expC | sigC) && (signProd != signC) ) { |
| completeCancellation: |
| uiZ = |
| packToF16UI( |
| (softfloat_roundingMode == softfloat_round_min), 0, 0 ); |
| } |
| uiZ: |
| uZ.ui = uiZ; |
| return uZ.f; |
| |
| } |
| |
