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Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/p16_to_i64.c')
| -rw-r--r-- | source/luametatex/source/libraries/softposit/source/p16_to_i64.c | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/p16_to_i64.c b/source/luametatex/source/libraries/softposit/source/p16_to_i64.c new file mode 100644 index 000000000..d06859443 --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/p16_to_i64.c @@ -0,0 +1,98 @@ + +/*============================================================================ + +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, 2017 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" + +int_fast64_t p16_to_i64( posit16_t pA ){ + union ui16_p16 uA; + int_fast64_t mask, tmp, iZ; + uint_fast16_t scale = 0, uiA; + bool sign, bitLast, bitNPlusOne; + + uA.p = pA; + uiA = uA.ui; + + // NaR + if (uiA==0x8000) return 0; + + sign = uiA>>15; + if (sign) uiA = -uiA & 0xFFFF; + + if (uiA <= 0x3000) + return 0; + else if (uiA < 0x4800) + iZ = 1; + else if (uiA <= 0x5400) + iZ = 2; + else{ + + uiA -= 0x4000; + + while (0x2000 & uiA) { + scale += 2; + uiA = (uiA - 0x2000) << 1; + } + uiA <<= 1; + if (0x2000 & uiA) scale++; + iZ = ((uint64_t)uiA | 0x2000) << 49; + + mask = 0x4000000000000000 >> scale; + + bitLast = (iZ & mask); + mask >>= 1; + tmp = (iZ & mask); + bitNPlusOne = tmp; + iZ ^= tmp; + tmp = iZ & (mask - 1); // bitsMore + iZ ^= tmp; + + if (bitNPlusOne) + if (bitLast | tmp) iZ += (mask << 1); + + iZ = (uint64_t)iZ >> (62 - scale); + + } + if (sign) iZ = -iZ; + return iZ; + +} + |