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Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/s_mulAddP8.c')
| -rw-r--r-- | source/luametatex/source/libraries/softposit/source/s_mulAddP8.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/s_mulAddP8.c b/source/luametatex/source/libraries/softposit/source/s_mulAddP8.c new file mode 100644 index 000000000..a99756678 --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/s_mulAddP8.c @@ -0,0 +1,243 @@ + +/*============================================================================ + +This C source file is part of the SoftPosit Posit Arithmetic Package +by S. H. Leong (Cerlane). + +Copyright 2017, 2018 A*STAR. 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 "platform.h" +#include "internals.h" + +//softposit_mulAdd_subC => (uiA*uiB)-uiC +//softposit_mulAdd_subProd => uiC - (uiA*uiB) +//Default is always op==0 +posit8_t softposit_mulAddP8( uint_fast8_t uiA, uint_fast8_t uiB, uint_fast8_t uiC, uint_fast8_t op ){ + + + union ui8_p8 uZ; + uint_fast8_t regZ, fracA, fracZ, regime, tmp; + bool signA, signB, signC, signZ, regSA, regSB, regSC, regSZ, bitNPlusOne=0, bitsMore=0, rcarry; + int_fast8_t kA=0, kC=0, kZ=0, shiftRight; + uint_fast16_t frac16C, frac16Z; + + //NaR + if ( uiA==0x80 || uiB==0x80 || uiC==0x80 ){ + uZ.ui = 0x80; + return uZ.p; + } + else if (uiA==0 || uiB==0){ + if (op == softposit_mulAdd_subC) + uZ.ui = -uiC; + else + uZ.ui = uiC; + return uZ.p; + } + + signA = signP8UI( uiA ); + signB = signP8UI( uiB ); + signC = signP8UI( uiC );//^ (op == softposit_mulAdd_subC); + signZ = signA ^ signB;// ^ (op == softposit_mulAdd_subProd); + + if(signA) uiA = (-uiA & 0xFF); + if(signB) uiB = (-uiB & 0xFF); + if(signC) uiC = (-uiC & 0xFF); + + regSA = signregP8UI(uiA); + regSB = signregP8UI(uiB); + regSC = signregP8UI(uiC); + + tmp = (uiA<<2) & 0xFF; + if (regSA){ + while (tmp>>7){ + kA++; + tmp= (tmp<<1) & 0xFF; + } + } + else{ + kA=-1; + while (!(tmp>>7)){ + kA--; + tmp= (tmp<<1) & 0xFF; + } + tmp&=0x7F; + } + fracA = (0x80 | tmp); //use first bit here for hidden bit to get more bits + + tmp = (uiB<<2) & 0xFF; + if (regSB){ + while (tmp>>7){ + kA++; + tmp= (tmp<<1) & 0xFF; + } + } + else{ + kA--; + while (!(tmp>>7)){ + kA--; + tmp= (tmp<<1) & 0xFF; + } + tmp&=0x7F; + } + frac16Z = (uint_fast16_t) fracA * (0x80 | tmp); + + rcarry = frac16Z>>15;//1st bit of frac16Z + if (rcarry){ + kA++; + frac16Z>>=1; + } + + if (uiC!=0){ + tmp = (uiC<<2) & 0xFF; + if (regSC){ + while (tmp>>7){ + kC++; + tmp= (tmp<<1) & 0xFF; + } + } + else{ + kC=-1; + while (!(tmp>>7)){ + kC--; + tmp= (tmp<<1) & 0xFF; + } + tmp&=0x7F; + } + frac16C = (0x80 | tmp) <<7 ; + shiftRight = (kA-kC); + + if (shiftRight<0){ // |uiC| > |Prod| + if (shiftRight<=-15) { + bitsMore = 1; + frac16Z=0; + } + else if (((frac16Z<<(16+shiftRight))&0xFFFF)!=0) bitsMore = 1; + if (signZ==signC) + frac16Z = frac16C + (frac16Z>>-shiftRight); + else {//different signs + frac16Z = frac16C - (frac16Z>>-shiftRight) ; + signZ=signC; + if (bitsMore) frac16Z-=1; + } + kZ = kC; + + } + else if (shiftRight>0){// |uiC| < |Prod| + + if(shiftRight>=15){ + bitsMore = 1; + frac16C = 0; + } + else if (((frac16C<<(16-shiftRight))&0xFFFF)!=0) bitsMore = 1; + if (signZ==signC) + frac16Z += (frac16C>>shiftRight); + else{ + frac16Z -= (frac16C>>shiftRight); + if (bitsMore) frac16Z-=1; + } + kZ = kA; + } + else{ + if(frac16C==frac16Z && signZ!=signC ){ //check if same number + uZ.ui = 0; + return uZ.p; + } + else{ + if (signZ==signC) + frac16Z += frac16C; + else{ + if (frac16Z<frac16C){ + frac16Z = frac16C - frac16Z; + signZ = signC; + } + else{ + frac16Z -= frac16C; + } + } + } + kZ = kA;// actually can be kC too, no diff + } + + rcarry = 0x8000 & frac16Z; //first left bit + if(rcarry){ + kZ ++; + frac16Z=(frac16Z>>1)&0x7FFF; + } + else { + + //for subtract cases + if (frac16Z!=0){ + while((frac16Z>>14)==0){ + kZ--; + frac16Z<<=1; + } + } + } + + } + else{ + kZ = kA; + } + + if(kZ<0){ + regZ = (-kZ & 0xFF); + regSZ = 0; + regime = 0x40>>regZ; + } + else{ + regZ = kZ+1; + regSZ=1; + regime = 0x7F - (0x7F>>regZ); + } + + if(regZ>6){ + //max or min pos. exp and frac does not matter. + (regSZ) ? (uZ.ui= 0x7F): (uZ.ui=0x1); + } + else{ + //remove hidden bits + frac16Z &= 0x3FFF; + + fracZ = (frac16Z >> regZ) >> 8; + + bitNPlusOne = ((frac16Z>>regZ) & 0x80); + uZ.ui = packToP8UI(regime, fracZ); + + if (bitNPlusOne){ + if ( (frac16Z<<(9-regZ)) &0xFFFF ) bitsMore =1; + uZ.ui += (uZ.ui&1) | bitsMore; + } + } + + if (signZ) uZ.ui = -uZ.ui & 0xFF; + return uZ.p; + +} + |