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Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/ui64_to_p32.c')
| -rw-r--r-- | source/luametatex/source/libraries/softposit/source/ui64_to_p32.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/ui64_to_p32.c b/source/luametatex/source/libraries/softposit/source/ui64_to_p32.c new file mode 100644 index 000000000..c32a00548 --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/ui64_to_p32.c @@ -0,0 +1,82 @@ + +/*============================================================================ + +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. + +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" + +posit32_t ui64_to_p32( uint64_t a ) { + + int_fast8_t k, log2 = 63;//length of bit (e.g. 18445618173802708992) in int (64 but because we have only 64 bits, so one bit off to accommodate that fact) + union ui32_p32 uZ; + uint_fast64_t uiA; + uint_fast64_t mask = 0x8000000000000000, fracA; + uint_fast32_t expA; + + + if ( a > 18445618173802708991ULL)//0xFFFBFFFFFFFFFFFF is the midpoint + uiA = 0x7FFFC000; // P32: 18446744073709552000 + else if ( a < 0x2 ) + uiA = (a << 30); + else { + fracA = a; + while ( !(fracA & mask) ) { + log2--; + fracA <<= 1; + } + + k = (log2 >> 2); + + expA = (log2 & 0x3) << (27 - k); + fracA = (fracA ^ mask); + + uiA = (0x7FFFFFFF ^ (0x3FFFFFFF >> k)) | expA | fracA>>(k+36); + + mask = 0x800000000 << k; //bitNPlusOne + + if (mask & fracA) { + if (((mask - 1) & fracA) | ((mask << 1) & fracA)) uiA++; + } + } + uZ.ui = uiA; + return uZ.p; +} |