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Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/p32_to_p16.c')
| -rw-r--r-- | source/luametatex/source/libraries/softposit/source/p32_to_p16.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/p32_to_p16.c b/source/luametatex/source/libraries/softposit/source/p32_to_p16.c new file mode 100644 index 000000000..f547aaef9 --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/p32_to_p16.c @@ -0,0 +1,122 @@ + +/*============================================================================ + +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. + +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 "platform.h" +#include "internals.h" + +posit16_t pX2_to_p16( posit_2_t pA ){ + posit32_t p32 = {.v = pA.v}; + return p32_to_p16(p32); +} + +posit16_t p32_to_p16( posit32_t pA ){ + + union ui32_p32 uA; + union ui16_p16 uZ; + uint_fast32_t uiA, tmp=0, exp_frac32A; + uint_fast16_t regime, exp_frac=0; + bool sign, regSA, bitsMore=0, bitNPlusOne=0; + int_fast16_t kA=0, regA; + + uA.p = pA; + uiA = uA.ui; + + if (uiA==0x80000000 || uiA==0 ){ + uZ.ui = (uint16_t)(uiA>>16); + return uZ.p; + } + + sign = signP32UI( uiA ); + if (sign) uiA = -uiA & 0xFFFFFFFF; + + if (uiA>0x7F600000) uZ.ui = 0x7FFF; + else if (uiA<0x00A00000) uZ.ui = 0x1; + else{ + regSA = signregP32UI(uiA); + + //regime + 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; + } + //exp and frac + exp_frac32A = tmp<<1; +printBinary(&exp_frac32A, 32); +printf("kA: %d\n", kA); + if(kA<0){ + regA = (-kA)<<1; + if (exp_frac32A&0x80000000) regA--; + exp_frac32A = (exp_frac32A<<1) &0xFFFFFFFF; + regSA = 0; + regime = 0x4000>>regA; + } + else{ + regA = (kA<<1)+1; + if (exp_frac32A&0x80000000) regA++; + exp_frac32A = (exp_frac32A<<1) &0xFFFFFFFF; + regSA=1; + regime = 0x7FFF - (0x7FFF>>regA); + } + if ((exp_frac32A>>(17+regA)) & 0x1) bitNPlusOne = 1; + if (regA<14) exp_frac = (uint16_t) (exp_frac32A>>(18+regA)); + + uZ.ui = regime + exp_frac; + if (bitNPlusOne){ + if ((exp_frac32A<<(15-regA)) & 0xFFFFFFFF) bitsMore=1; + uZ.ui += (bitNPlusOne & (uZ.ui&1)) | ( bitNPlusOne & bitsMore); + } + } + + + + + if (sign) uZ.ui = (-uZ.ui & 0xFFFF); + return uZ.p; +} + |