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Diffstat (limited to 'source/luametatex/source/libraries/softposit/source/i32_to_p32.c')
-rw-r--r-- | source/luametatex/source/libraries/softposit/source/i32_to_p32.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/i32_to_p32.c b/source/luametatex/source/libraries/softposit/source/i32_to_p32.c new file mode 100644 index 000000000..b822d9e39 --- /dev/null +++ b/source/luametatex/source/libraries/softposit/source/i32_to_p32.c @@ -0,0 +1,87 @@ + +/*============================================================================ + +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 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" + + +posit32_t i32_to_p32( int32_t iA ) { + int_fast8_t k, log2 = 31;//length of bit (e.g. 4294966271) in int (32 but because we have only 32 bits, so one bit off to accommodate that fact) + union ui32_p32 uZ; + uint_fast32_t uiA; + uint_fast32_t expA, mask = 0x80000000, fracA; + bool sign; + + if (iA < -2147483135){ //-2147483648 to -2147483136 rounds to P32 value -2147483648 + uZ.ui = 0x80500000; + return uZ.p; + } + + sign = iA>>31; + if(sign) iA = -iA &0xFFFFFFFF; + + if ( iA >2147483135)//2147483136 to 2147483647 rounds to P32 value (2147483648)=> 0x7FB00000 + uiA = 0x7FB00000; + else if ( iA < 0x2 ) + uiA = (iA << 30); + else { + fracA = iA; + while ( !(fracA & mask) ) { + log2--; + fracA <<= 1; + } + k = (log2 >> 2); + expA = (log2 & 0x3) << (27 - k); + fracA = (fracA ^ mask); + uiA = (0x7FFFFFFF ^ (0x3FFFFFFF >> k)) | expA | fracA>>(k+4); + + mask = 0x8 << k; //bitNPlusOne + + if (mask & fracA) + if (((mask - 1) & fracA) | ((mask << 1) & fracA)) uiA++; + + } + (sign) ? (uZ.ui = -uiA &0xFFFFFFFF) : (uZ.ui = uiA); + return uZ.p; +} + + |