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Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/c_convertPosit16ToDec.c')
| -rw-r--r-- | source/luametatex/source/libraries/softposit/source/c_convertPosit16ToDec.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/c_convertPosit16ToDec.c b/source/luametatex/source/libraries/softposit/source/c_convertPosit16ToDec.c new file mode 100644 index 000000000..9befa42ed --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/c_convertPosit16ToDec.c @@ -0,0 +1,172 @@ + +/*============================================================================ + +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" + + +double convertP16ToDouble(posit16_t a){ + union ui16_p16 uZ; + //posit16 p16; + double d16; + uZ.p = a; + + if (uZ.ui==0){ + return 0; + } + else if(uZ.ui==0x7FFF){ //maxpos -> 32767 + return 268435456; + } + else if (uZ.ui==0x8001){ //-maxpos -> 32769 + return -268435456; + } + else if (uZ.ui == 0x8000){ //NaR -> 32768 + return NAN; + } + + bool regS, sign; + uint_fast16_t reg, shift=2, frac; + int_fast16_t k=0; + int_fast8_t exp; + double fraction_max; + + sign = signP16UI( uZ.ui ); + if (sign) + uZ.ui = -uZ.ui & 0xFFFF; + regS = signregP16UI( uZ.ui ); + + uint_fast16_t tmp = (uZ.ui<<2) & 0xFFFF; + if (regS){ + while (tmp>>15){ + k++; + shift++; + tmp= (tmp<<1) & 0xFFFF; + } + reg = k+1; + } + else{ + k=-1; + while (!(tmp>>15)){ + k--; + shift++; + tmp= (tmp<<1) & 0xFFFF; + } + tmp&=0x7FFF; + reg =-k; + } + exp = tmp>>14; + frac = (tmp & 0x3FFF) >> shift; + + + fraction_max = pow(2, 13-reg) ; + d16 = (double)( pow(4, k)* pow(2, exp) * (1+((double)frac/fraction_max)) ); + + if (sign) + d16 = -d16; + + return d16; +} + +#ifdef SOFTPOSIT_QUAD + __float128 convertP16ToQuadDec(posit16_t a){ + + union ui16_p16 uZ; + __float128 p16; + uZ.p = a; + + if (uZ.ui==0){ + p16 = 0; + return p16; + } + else if(uZ.ui==0x7FFF){ //maxpos -> 32767 + p16 = 268435456; + return p16; + } + else if (uZ.ui==0x8001){ //-maxpos -> 32769 + p16 = -268435456; + return p16; + } + else if (uZ.ui == 0x8000){ //NaR -> 32768 + p16 = INFINITY; + return p16; + } + + bool regS, sign; + uint_fast16_t reg, shift=2, frac; + int_fast16_t k=0; + int_fast8_t exp; + __float128 fraction_max; + + sign = signP16UI( uZ.ui ); + if (sign) + uZ.ui = -uZ.ui & 0xFFFF; + regS = signregP16UI( uZ.ui ); + + uint_fast16_t tmp = (uZ.ui<<2) & 0xFFFF; + if (regS){ + while (tmp>>15){ + k++; + shift++; + tmp= (tmp<<1) & 0xFFFF; + } + reg = k+1; + } + else{ + k=-1; + while (!(tmp>>15)){ + k--; + shift++; + tmp= (tmp<<1) & 0xFFFF; + } + tmp&=0x7FFF; + reg =-k; + } + exp = tmp>>14; + frac = (tmp & 0x3FFF) >> shift; + + + fraction_max = pow(2, 13-reg) ; + p16 = (__float128)( pow(4, k)* pow(2, exp) * (1+((__float128)frac/fraction_max)) ); + + if (sign) + p16 = -p16; + + return p16; + + } +#endif + |