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Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/c_convertDecToPosit8.c')
| -rw-r--r-- | source/luametatex/source/libraries/softposit/source/c_convertDecToPosit8.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/c_convertDecToPosit8.c b/source/luametatex/source/libraries/softposit/source/c_convertDecToPosit8.c new file mode 100644 index 000000000..16d5f527f --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/c_convertDecToPosit8.c @@ -0,0 +1,211 @@ +/*============================================================================ + +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" + +void checkExtraTwoBitsP8(double f8, double temp, bool * bitsNPlusOne, bool * bitsMore ){ + temp /= 2; + if (temp<=f8){ + *bitsNPlusOne = 1; + f8-=temp; + } + if (f8>0) + *bitsMore = 1; +} +uint_fast16_t convertFractionP8(double f8, uint_fast8_t fracLength, bool * bitsNPlusOne, bool * bitsMore ){ + + uint_fast8_t frac=0; + + if(f8==0) return 0; + else if(f8==INFINITY) return 0x80; + + f8 -= 1; //remove hidden bit + if (fracLength==0) + checkExtraTwoBitsP8(f8, 1.0, bitsNPlusOne, bitsMore); + else{ + double temp = 1; + while (true){ + temp /= 2; + if (temp<=f8){ + f8-=temp; + fracLength--; + frac = (frac<<1) + 1; //shift in one + if (f8==0){ + //put in the rest of the bits + frac <<= (uint_fast8_t)fracLength; + break; + } + + if (fracLength == 0){ + checkExtraTwoBitsP8(f8, temp, bitsNPlusOne, bitsMore); + + break; + } + } + else{ + frac <<= 1; //shift in a zero + fracLength--; + if (fracLength == 0){ + checkExtraTwoBitsP8(f8, temp, bitsNPlusOne, bitsMore); + break; + } + } + } + } + + + //printf("convertfloat: frac:%d f16: %.26f bitsNPlusOne: %d, bitsMore: %d\n", frac, f16, bitsNPlusOne, bitsMore); + + return frac; +} +posit8_t convertDoubleToP8(double f8){ + union ui8_p8 uZ; + bool sign; + uint_fast8_t reg, frac=0; + bool bitNPlusOne=0, bitsMore=0; + + (f8>=0) ? (sign=0) : (sign=1); + // sign: 1 bit, frac: 8 bits, mantisa: 23 bits + //sign = a.parts.sign; + //frac = a.parts.fraction; + //exp = a.parts.exponent; + + if (f8 == 0 ){ + uZ.ui = 0; + return uZ.p; + } + else if(f8 == INFINITY || f8 == -INFINITY || f8 == NAN){ + uZ.ui = 0x80; + return uZ.p; + } + else if (f8 == 1) { + uZ.ui = 0x40; + return uZ.p; + } + else if (f8 == -1){ + uZ.ui = 0xC0; + return uZ.p; + } + else if (f8 >= 64){ + //maxpos + uZ.ui = 0x7F; + return uZ.p; + } + else if (f8 <= -64){ + // -maxpos + uZ.ui = 0x81; + return uZ.p; + } + else if(f8 <= 0.015625 && !sign){ + //minpos + uZ.ui = 0x1; + return uZ.p; + } + else if(f8 >= -0.015625 && sign){ + //-minpos + uZ.ui = 0xFF; + return uZ.p; + } + else if (f8>1 || f8<-1){ + if (sign){ + //Make negative numbers positive for easier computation + f8 = -f8; + } + reg = 1; //because k = m-1; so need to add back 1 + // minpos + if (f8 <= 0.015625){ + uZ.ui = 1; + } + else{ + //regime + while (f8>=2){ + f8 *=0.5; + reg++; + } + + //rounding off regime bits + if (reg>6 ) + uZ.ui= 0x7F; + else{ + int8_t fracLength = 6-reg; + frac = convertFractionP8 (f8, fracLength, &bitNPlusOne, &bitsMore); + uint_fast8_t regime = 0x7F - (0x7F>>reg); + uZ.ui = packToP8UI(regime, frac); + if (bitNPlusOne) + uZ.ui += ((uZ.ui&1) | bitsMore ); + } + if(sign) uZ.ui = -uZ.ui & 0xFF; + } + } + else if (f8 < 1 || f8 > -1 ){ + + if (sign){ + //Make negative numbers positive for easier computation + f8 = -f8; + } + reg = 0; + + //regime + //printf("here we go\n"); + while (f8<1){ + f8 *= 2; + reg++; + } + //rounding off regime bits + if (reg>6 ) + uZ.ui=0x1; + else{ + int_fast8_t fracLength = 6-reg; + frac = convertFractionP8 (f8, fracLength, &bitNPlusOne, &bitsMore); + uint_fast8_t regime = 0x40>>reg; + uZ.ui = packToP8UI(regime, frac); + if (bitNPlusOne) + uZ.ui += ((uZ.ui&1) | bitsMore ); + } + if(sign) uZ.ui = -uZ.ui & 0xFF; + + } + else { + //NaR - for NaN, INF and all other combinations + uZ.ui = 0x80; + } + return uZ.p; +} + + + |