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author | Hans Hagen <pragma@wxs.nl> | 2023-04-27 00:04:07 +0200 |
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committer | Context Git Mirror Bot <phg@phi-gamma.net> | 2023-04-27 00:04:07 +0200 |
commit | 6b25a7a970ba9553adf8077ef2eecb50a5d77818 (patch) | |
tree | f06e40077ba9e55af4bf6cab52313f79f8ea84a8 /source/luametatex/source/libraries/softposit/source/i64_to_p8.c | |
parent | 657457ef4a08c1f000f272e00f654f4064cc37bd (diff) | |
download | context-6b25a7a970ba9553adf8077ef2eecb50a5d77818.tar.gz |
2023-04-26 23:31:00
Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/i64_to_p8.c')
-rw-r--r-- | source/luametatex/source/libraries/softposit/source/i64_to_p8.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/i64_to_p8.c b/source/luametatex/source/libraries/softposit/source/i64_to_p8.c new file mode 100644 index 000000000..646d7e4be --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/i64_to_p8.c @@ -0,0 +1,90 @@ + +/*============================================================================ + +This C source file is part of the SoftPosit Posit Arithmetic Package +by S. H. Leong (Cerlane) and John Gustafson. + +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. + +Copyright 2011, 2012, 2013, 2014, 2015, 2016 The Regents of the University of +California. 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 <stdint.h> + +#include "platform.h" +#include "internals.h" + +posit8_t i64_to_p8( int64_t iA ){ + int_fast8_t k, log2 = 6;//length of bit + union ui8_p8 uZ; + uint_fast8_t uiA; + uint_fast64_t mask = 0x40, fracA; + bool sign; + + if (iA < -48){ //-48 to -MAX_INT rounds to P32 value -268435456 + uZ.ui = 0x81; //-maxpos + return uZ.p; + } + + sign = iA>>63; + if(sign){ + iA = -iA; + } + + if ( iA > 48 ) { + uiA = 0x7F; + } + else if ( iA < 2 ){ + uiA = (iA << 6); + } + else { + fracA = iA; + while ( !(fracA & mask) ) { + log2--; + fracA <<= 1; + } + + k = log2; + + fracA = (fracA ^ mask); + + uiA = (0x7F ^ (0x3F >> k)) | ( fracA >> (k+1) ) ; + + mask = 0x1 << k; //bitNPlusOne + if (mask & fracA) { + if (((mask - 1) & fracA) | ((mask << 1) & fracA)) uiA++; + } + } + (sign) ? (uZ.ui = -uiA &0xFF) : (uZ.ui = uiA); + return uZ.p; +} |