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Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/c_convertQuire32ToPosit32.c')
| -rw-r--r-- | source/luametatex/source/libraries/softposit/source/c_convertQuire32ToPosit32.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/c_convertQuire32ToPosit32.c b/source/luametatex/source/libraries/softposit/source/c_convertQuire32ToPosit32.c new file mode 100644 index 000000000..c3de4b768 --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/c_convertQuire32ToPosit32.c @@ -0,0 +1,183 @@ + +/*============================================================================ + +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 <math.h> + +#include "platform.h" +#include "internals.h" + + + +posit32_t q32_to_p32(quire32_t qA){ + + union ui512_q32 uZ; + union ui32_p32 uA; + uint_fast32_t regA, fracA = 0, shift=0, regime; + uint_fast64_t frac64A; + bool sign, regSA=0, bitNPlusOne=0, bitsMore=0; + int_fast32_t expA = 0; + int i; + + if (isQ32Zero(qA)){ + uA.ui=0; + return uA.p; + } + //handle NaR + else if (isNaRQ32(qA)){ + uA.ui=0x80000000; + return uA.p; + } + + uZ.q = qA; + + sign = uZ.ui[0]>>63; + + if(sign){ + for (i=7; i>=0; i--){ + if (uZ.ui[i]>0){ + uZ.ui[i] = - uZ.ui[i]; + i--; + while(i>=0){ + uZ.ui[i] = ~uZ.ui[i]; + i--; + } + break; + } + } + } + //minpos and maxpos + + int noLZ =0; + + for (i=0; i<8; i++){ + if (uZ.ui[i]==0){ + noLZ+=64; + } + else{ + uint_fast64_t tmp = uZ.ui[i]; + int noLZtmp = 0; + + while (!(tmp>>63)){ + noLZtmp++; + tmp= (tmp<<1); + } + + noLZ+=noLZtmp; + frac64A = tmp; + if (i!=7 && noLZtmp!=0){ + frac64A+= ( uZ.ui[i+1]>>(64-noLZtmp) ); + if( uZ.ui[i+1] & (((uint64_t)0x1<<(64-noLZtmp))-1) ) + bitsMore=1; + i++; + } + i++; + while(i<8){ + if (uZ.ui[i]>0){ + bitsMore = 1;; + break; + } + i++; + } + break; + } + } + + //default dot is between bit 271 and 272, extreme left bit is bit 0. Last right bit is bit 511. + //Equations derived from quire32_mult last_pos = 271 - (kA<<2) - expA and first_pos = last_pos - frac_len + int kA=(271-noLZ) >> 2; + expA = 271 - noLZ - (kA<<2) ; + + + if(kA<0){ + //regA = (-kA & 0xFFFF); + regA = -kA; + regSA = 0; + regime = 0x40000000>>regA; + } + else{ + regA = kA+1; + regSA=1; + regime = 0x7FFFFFFF - (0x7FFFFFFF>>regA); + } + + + if(regA>30){ + //max or min pos. exp and frac does not matter. + (regSA) ? (uA.ui= 0x7FFFFFFF): (uA.ui=0x1); + } + else{ + + //remove hidden bit + frac64A&=0x7FFFFFFFFFFFFFFF; + + shift = regA+35; //2 es bit, 1 sign bit and 1 r terminating bit , 31+4 + + fracA = frac64A>>shift; + + if (regA<=28){ + bitNPlusOne = (frac64A>>(shift-1)) & 0x1; + expA<<= (28-regA); + if (frac64A<<(65-shift)) bitsMore=1; + + } + else { + if (regA==30){ + bitNPlusOne = expA&0x2; + bitsMore = (expA&0x1); + expA = 0; + } + else if (regA==29){ + bitNPlusOne = expA&0x1; + expA>>=1; //taken care of by the pack algo + } + if (frac64A>0){ + fracA=0; + bitsMore =1; + } + } + + uA.ui = packToP32UI(regime, expA, fracA); + if (bitNPlusOne) + uA.ui += (uA.ui&1) | bitsMore; + + } + if (sign) uA.ui = -uA.ui & 0xFFFFFFFF; + + return uA.p; + +} + + + |