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Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/p16_mul.c')
-rw-r--r-- | source/luametatex/source/libraries/softposit/source/p16_mul.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/p16_mul.c b/source/luametatex/source/libraries/softposit/source/p16_mul.c new file mode 100644 index 000000000..bf9c8b967 --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/p16_mul.c @@ -0,0 +1,171 @@ + +/*============================================================================ + +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. + +This C source file was based on SoftFloat IEEE Floating-Point Arithmetic +Package, Release 3d, by John R. Hauser. + +Copyright 2011, 2012, 2013, 2014, 2015, 2016, 2017 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 "platform.h" +#include "internals.h" + + +posit16_t p16_mul( posit16_t pA, posit16_t pB ){ + + union ui16_p16 uA, uB, uZ; + uint_fast16_t uiA, uiB; + uint_fast16_t regA, fracA, regime, tmp; + bool signA, signB, signZ, regSA, regSB, bitNPlusOne=0, bitsMore=0, rcarry; + int_fast8_t expA; + int_fast8_t kA=0; + uint_fast32_t frac32Z; + + uA.p = pA; + uiA = uA.ui; + uB.p = pB; + uiB = uB.ui; + + + //NaR or Zero + if ( uiA==0x8000 || uiB==0x8000 ){ + uZ.ui = 0x8000; + return uZ.p; + } + else if (uiA==0 || uiB==0){ + uZ.ui = 0; + return uZ.p; + } + + signA = signP16UI( uiA ); + signB = signP16UI( uiB ); + signZ = signA ^ signB; + + if(signA) uiA = (-uiA & 0xFFFF); + if(signB) uiB = (-uiB & 0xFFFF); + + regSA = signregP16UI(uiA); + regSB = signregP16UI(uiB); + + tmp = (uiA<<2) & 0xFFFF; + if (regSA){ + while (tmp>>15){ + kA++; + tmp= (tmp<<1) & 0xFFFF; + } + } + else{ + kA=-1; + while (!(tmp>>15)){ + kA--; + tmp= (tmp<<1) & 0xFFFF; + } + tmp&=0x7FFF; + } + expA = tmp>>14; + fracA = (0x4000 | tmp); + + tmp = (uiB<<2) & 0xFFFF; + if (regSB){ + while (tmp>>15){ + kA++; + tmp= (tmp<<1) & 0xFFFF; + } + } + else{ + kA--; + while (!(tmp>>15)){ + kA--; + tmp= (tmp<<1) & 0xFFFF; + } + tmp&=0x7FFF; + } + expA += tmp>>14; + frac32Z = (uint_fast32_t) fracA * (0x4000 | tmp); + + if (expA>1){ + kA++; + expA ^=0x2; + } + + rcarry = frac32Z>>29;//3rd bit of frac32Z + if (rcarry){ + if (expA) kA ++; + expA^=1; + frac32Z>>=1; + } + + if(kA<0){ + regA = (-kA & 0xFFFF); + regSA = 0; + regime = 0x4000>>regA; + } + else{ + regA = kA+1; + regSA=1; + regime = 0x7FFF - (0x7FFF>>regA); + } + + if(regA>14){ + //max or min pos. exp and frac does not matter. + (regSA) ? (uZ.ui= 0x7FFF): (uZ.ui=0x1); + } + else{ + //remove carry and rcarry bits and shift to correct position + frac32Z = (frac32Z&0xFFFFFFF) >> (regA-1); + fracA = (uint_fast16_t) (frac32Z>>16); + + if (regA!=14) bitNPlusOne |= (0x8000 & frac32Z) ; + else if (fracA>0){ + fracA=0; + bitsMore =1; + } + if (regA==14 && expA) bitNPlusOne = 1; + + //sign is always zero + uZ.ui = packToP16UI(regime, regA, expA, fracA); + //n+1 frac bit is 1. Need to check if another bit is 1 too if not round to even + if (bitNPlusOne){ + if (0x7FFF & frac32Z) bitsMore=1; + uZ.ui += (uZ.ui&1) | bitsMore; + } + } + + if (signZ) uZ.ui = -uZ.ui & 0xFFFF; + return uZ.p; +} + + + |