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Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/p32_to_pX1.c')
-rw-r--r-- | source/luametatex/source/libraries/softposit/source/p32_to_pX1.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/p32_to_pX1.c b/source/luametatex/source/libraries/softposit/source/p32_to_pX1.c new file mode 100644 index 000000000..ec74b6f56 --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/p32_to_pX1.c @@ -0,0 +1,131 @@ + +/*============================================================================ + +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" + + +posit_1_t p32_to_pX1( posit32_t pA, int x ){ + + union ui32_p32 uA; + union ui32_pX1 uZ; + uint_fast32_t uiA, tmp, regime; + uint_fast32_t exp_frac32A=0; + bool sign, regSA, bitNPlusOne, bitsMore; + int_fast8_t kA=0, regA; + + if (x<2 || x>32){ + uZ.ui = 0x80000000; + return uZ.p; + } + + uA.p = pA; + uiA = uA.ui; + + if (uiA==0x80000000 || uiA==0 ){ + uZ.ui = uiA; + return uZ.p; + } + + sign = signP32UI( uiA ); + if (sign) uiA = -uiA & 0xFFFFFFFF; + + if (x==2){ + uZ.ui=(uiA>0)?(0x40000000):(0); + } + else { + regSA = signregP32UI(uiA); + + 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; +//printf("kA: %d\n", kA); +//printBinary(&exp_frac32A, 32); + if(kA<0){ + regA = (-kA)<<1; + if (exp_frac32A&0x80000000) regA--; + exp_frac32A = (exp_frac32A<<1) &0xFFFFFFFF; + regSA = 0; + regime = 0x40000000>>regA; + } + else{ + regA = (kA<<1)+1; + if (exp_frac32A&0x80000000) regA++; + exp_frac32A = (exp_frac32A<<1) &0xFFFFFFFF; + regSA=1; + regime = 0x7FFFFFFF - (0x7FFFFFFF>>regA); + } + + if(regA>(x-2)){ + //max or min pos. exp and frac does not matter. + uZ.ui=(regSA) ? (0x7FFFFFFF & ((int32_t)0x80000000>>(x-1)) ): (0x1 << (32-x)); + } + else{ + + bitNPlusOne = (exp_frac32A >>(regA+33-x))&0x1; + bitsMore = exp_frac32A&(0x7FFFFFFF>>(x-regA-2)); + + if (regA<30) exp_frac32A >>=(2+regA); + else exp_frac32A=0; + uZ.ui = regime + (exp_frac32A & ((int32_t)0x80000000>>(x-1)) ); + + if (uZ.ui==0) uZ.ui = 0x1<<(32-x); + else if (bitNPlusOne){ + uZ.ui += (uint32_t)(((uZ.ui>>(32-x))&1) | bitsMore) << (32-x) ; + } + } + + } + if (sign) uZ.ui = (-uZ.ui & 0xFFFFFFFF); + return uZ.p; +} + |