diff options
Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/i32_to_p16.c')
-rw-r--r-- | source/luametatex/source/libraries/softposit/source/i32_to_p16.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/i32_to_p16.c b/source/luametatex/source/libraries/softposit/source/i32_to_p16.c new file mode 100644 index 000000000..c7ec6a24b --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/i32_to_p16.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 "platform.h" +#include "internals.h" + +posit16_t i32_to_p16( int32_t iA ){ + int_fast8_t k, log2 = 25; + union ui16_p16 uZ; + uint_fast16_t uiA; + uint_fast32_t expA, mask = 0x02000000, fracA; + bool sign; + + + if (iA < -134217728){ //-2147483648 to -134217729 rounds to P32 value -268435456 + uZ.ui = 0x8001; //-maxpos + return uZ.p; + } + + sign = iA>>31; + if(sign){ + iA = -iA &0xFFFFFFFF; + } + + if( iA > 134217728 ) { //134217729 to 2147483647 rounds to P32 value 268435456 + uiA = 0x7FFF; //maxpos + } + else if ( iA > 0x02FFFFFF ){ + uiA = 0x7FFE; + } + else if ( iA < 2 ){ + uiA = (iA << 14); + } + else { + fracA = iA; + while ( !(fracA & mask) ) { + log2--; + fracA <<= 1; + } + k = log2 >> 1; + expA = (log2 & 0x1) << (12 - k); + fracA = (fracA ^ mask); + + uiA = (0x7FFF ^ (0x3FFF >> k)) | expA | ( fracA >> (k + 13)); + mask = 0x1000 << k; //bitNPlusOne + if (mask & fracA) { + if (((mask - 1) & fracA) | ((mask << 1) & fracA)) uiA++; + } + } + (sign) ? (uZ.ui = -uiA &0xFFFF) : (uZ.ui = uiA); + return uZ.p; +} |