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Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/p16_div.c')
| -rw-r--r-- | source/luametatex/source/libraries/softposit/source/p16_div.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/p16_div.c b/source/luametatex/source/libraries/softposit/source/p16_div.c new file mode 100644 index 000000000..2786234ba --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/p16_div.c @@ -0,0 +1,186 @@ + +/*============================================================================ + +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 <stdlib.h> + +#include "platform.h" +#include "internals.h" + +posit16_t p16_div( posit16_t pA, posit16_t pB ) { + union ui16_p16 uA, uB, uZ; + uint_fast16_t uiA, uiB, fracA, fracB, regA, regime, tmp; + bool signA, signB, signZ, regSA, regSB, bitNPlusOne=0, bitsMore=0, rcarry; + int_fast8_t expA, kA=0; + uint_fast32_t frac32A, frac32Z, rem; + div_t divresult; + + uA.p = pA; + uiA = uA.ui; + uB.p = pB; + uiB = uB.ui; + + //Zero or infinity + if ( uiA==0x8000 || uiB==0x8000 || uiB==0){ +#ifdef SOFTPOSIT_EXACT + uZ.ui.v = 0x8000; + uZ.ui.exact = 0; +#else + uZ.ui = 0x8000; +#endif + return uZ.p; + } + else if (uiA==0){ +#ifdef SOFTPOSIT_EXACT + uZ.ui.v = 0; + if ( (uiA==0 && uiA.ui.exact) || (uiB==0 && uiB.ui.exact) ) + uZ.ui.exact = 1; + else + uZ.ui.exact = 0; +#else + uZ.ui = 0; +#endif + 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); + frac32A = fracA<<14; + + tmp = (uiB<<2) & 0xFFFF; + if (regSB){ + while (tmp>>15){ + kA--; + tmp= (tmp<<1) & 0xFFFF; + } + fracB = (0x4000 | tmp); + } + else{ + kA++; + while (!(tmp>>15)){ + kA++; + tmp= (tmp<<1) & 0xFFFF; + } + tmp&=0x7FFF; + fracB = (0x4000 | (0x7FFF & tmp)); + } + expA -= tmp>>14; + + divresult = div (frac32A,fracB); + frac32Z = divresult.quot; + rem = divresult.rem; + + if (expA<0){ + expA=1; + kA--; + } + if (frac32Z!=0){ + rcarry = frac32Z >> 14; // this is the hidden bit (14th bit) , extreme right bit is bit 0 + if (!rcarry){ + if (expA==0) 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 &= 0x3FFF; + fracA = (uint_fast16_t)frac32Z >> (regA+1); + + if (regA!=14) bitNPlusOne = (frac32Z >> regA) & 0x1; + 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); + + if (bitNPlusOne){ + ( ((1<<regA)-1) & frac32Z ) ? (bitsMore=1) : (bitsMore=0); + if (rem) bitsMore =1; + //n+1 frac bit is 1. Need to check if another bit is 1 too if not round to even + uZ.ui += (uZ.ui&1) | bitsMore; + } + } + if (signZ) uZ.ui = -uZ.ui & 0xFFFF; + + return uZ.p; +} + |