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Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/quire32_fdp_sub.c')
| -rw-r--r-- | source/luametatex/source/libraries/softposit/source/quire32_fdp_sub.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/quire32_fdp_sub.c b/source/luametatex/source/libraries/softposit/source/quire32_fdp_sub.c new file mode 100644 index 000000000..1a132eefd --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/quire32_fdp_sub.c @@ -0,0 +1,205 @@ +/*============================================================================ + +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 <inttypes.h> +#include <string.h> + +#include "platform.h" +#include "internals.h" + +//c-(a*b) + +quire_2_t qX2_fdp_sub( quire_2_t q, posit_2_t pA, posit_2_t pB ){ + union ui512_q32 uQZ; + union ui32_p32 uA, uB; + memcpy(uQZ.ui, q.v, 8*sizeof(uint64_t)); + uA.ui = pA.v; + uB.ui = pB.v; + uQZ.q = q32_fdp_sub(uQZ.q, uA.p, uB.p); + memcpy(q.v, uQZ.ui, 8*sizeof(uint64_t)); + return q; +} + +quire32_t q32_fdp_sub( quire32_t q, posit32_t pA, posit32_t pB ){ + + union ui32_p32 uA, uB; + union ui512_q32 uZ, uZ1, uZ2; + uint_fast32_t uiA, uiB; + uint_fast32_t fracA, tmp; + bool signA, signB, signZ2, regSA, regSB, rcarry; + int_fast32_t expA; + int_fast16_t kA=0, shiftRight=0; + uint_fast64_t frac64Z; + //For sub + bool rcarryb, b1, b2, rcarryZ; + + uZ1.q = q; + + uA.p = pA; + uiA = uA.ui; + uB.p = pB; + uiB = uB.ui; + + uZ2.q = q32Clr(uZ2.q); //set it to zero + //NaR + if (isNaRQ32(q) || isNaRP32UI(uA.ui) || isNaRP32UI(uB.ui)){ + //set to all zeros + uZ2.ui[0]=0x8000000000000000ULL; + return uZ2.q; + } + else if (uiA==0 || uiB==0) + return q; + + //max pos (sign plus and minus) + signA = signP32UI( uiA ); + signB = signP32UI( uiB ); + signZ2 = signA ^ signB; + + if(signA) uiA = (-uiA & 0xFFFFFFFF); + if(signB) uiB = (-uiB & 0xFFFFFFFF); + + regSA = signregP32UI(uiA); + regSB = signregP32UI(uiB); + + tmp = (uiA<<2) & 0xFFFFFFFF; + if (regSA){ + while (tmp>>31){ + kA++; + tmp= (tmp<<1) & 0xFFFFFFFF; + } + } + else{ + kA=-1; + while (!(tmp>>31)){ + kA--; + tmp= (tmp<<1) & 0xFFFFFFFF; + } + tmp&=0x7FFFFFFF; + } + expA = tmp>>29; //to get 2 bits + fracA = ((tmp<<2) | 0x80000000) & 0xFFFFFFFF; + + tmp = (uiB<<2) & 0xFFFFFFFF; + if (regSB){ + while (tmp>>31){ + kA++; + tmp= (tmp<<1) & 0xFFFFFFFF; + } + } + else{ + kA--; + while (!(tmp>>31)){ + kA--; + tmp= (tmp<<1) & 0xFFFFFFFF; + } + tmp&=0x7FFFFFFF; + } + expA += tmp>>29; + frac64Z = (uint_fast64_t) fracA * (((tmp<<2) | 0x80000000) & 0xFFFFFFFF); + + if (expA>3){ + kA++; + expA&=0x3; // -=4 + } + //Will align frac64Z such that hidden bit is the first bit on the left. + rcarry = frac64Z>>63;//1st bit of frac64Z + if (rcarry){ + expA++; + if (expA>3){ + kA ++; + expA&=0x3; + } + //frac64Z>>=1; + } + else + frac64Z<<=1; + + //default dot is between bit 271 and 272, extreme left bit is bit 0. Last right bit is bit 512. + //Minpos is 120 position to the right of binary point (dot) + //Scale = 2^es * k + e => 2k + e + int firstPos = 271 - (kA<<2) - expA; + + //Moving in chunk of 64. If it is in first chunk, a part might be in the chunk right to it. Simply have to handle that. + int i; + for (i=0; i<8; i++){ + if (firstPos<(i+1)*64){ + //Need to check how much of the fraction is in the next 64 bits + shiftRight = firstPos - (i*64); + uZ2.ui[i] = frac64Z >> shiftRight; + if (i!=7 && shiftRight!=0) uZ2.ui[i+1] = frac64Z << (64 - shiftRight); + break; + } + } + + + //This is the only difference from ADD (signZ2) and (!signZ2) + if (!signZ2){ + for (i=7; i>=0; i--){ + if (uZ2.ui[i]>0){ + uZ2.ui[i] = - uZ2.ui[i]; + i--; + while(i>=0){ + uZ2.ui[i] = ~uZ2.ui[i]; + i--; + } + break; + } + } + + } + + //Subtraction + for (i=7; i>=0; i--){ + b1 = uZ1.ui[i] & 0x1; + b2 = uZ2.ui[i] & 0x1; + if (i==7){ + rcarryb = b1 & b2; + uZ.ui[i] = (uZ1.ui[i]>>1) + (uZ2.ui[i]>>1) + rcarryb; + rcarryZ = uZ.ui[i]>>63; + uZ.ui[i] = (uZ.ui[i]<<1 | (b1^b2) ); + } + else{ + int_fast8_t rcarryb3 = b1 + b2 + rcarryZ; + uZ.ui[i] = (uZ1.ui[i]>>1) + (uZ2.ui[i]>>1) + (rcarryb3>>1); + rcarryZ = uZ.ui[i]>>63; + uZ.ui[i] = (uZ.ui[i]<<1 | (rcarryb3 & 0x1) ); + } + + } + + //Exception handling + if (isNaRQ32(uZ.q) ) uZ.q.v[0]=0; + + return uZ.q; +} |