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Diffstat (limited to 'source/f128_roundToInt.c')
| -rw-r--r-- | source/f128_roundToInt.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/source/f128_roundToInt.c b/source/f128_roundToInt.c new file mode 100644 index 0000000..5b6e0af --- /dev/null +++ b/source/f128_roundToInt.c @@ -0,0 +1,157 @@ + +/*============================================================================ + +This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic +Package, Release 3, by John R. Hauser. + +Copyright 2011, 2012, 2013, 2014 The Regents of the University of California +(Regents). All Rights Reserved. Redistribution and use in source and binary +forms, with or without modification, are permitted provided that the following +conditions are met: + +Redistributions of source code must retain the above copyright notice, +this list of conditions, and the following two paragraphs of disclaimer. +Redistributions in binary form must reproduce the above copyright notice, +this list of conditions, and the following two paragraphs of disclaimer in the +documentation and/or other materials provided with the distribution. Neither +the name of the Regents nor the names of its contributors may be used to +endorse or promote products derived from this software without specific prior +written permission. + +IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, +SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING +OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS +BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED +TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR +PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED +HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE +MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. + +=============================================================================*/ + +#include <stdbool.h> +#include <stdint.h> +#include "platform.h" +#include "internals.h" +#include "specialize.h" +#include "softfloat.h" + +float128_t + f128_roundToInt( float128_t a, uint_fast8_t roundingMode, bool exact ) +{ + union ui128_f128 uA; + uint_fast64_t uiA64, uiA0; + int_fast32_t exp; + struct uint128 uiZ; + uint_fast64_t lastBitMask, roundBitsMask; + bool roundNearEven; + union ui128_f128 uZ; + + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + uA.f = a; + uiA64 = uA.ui.v64; + uiA0 = uA.ui.v0; + exp = expF128UI64( uiA64 ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( 0x402F <= exp ) { + /*-------------------------------------------------------------------- + *--------------------------------------------------------------------*/ + if ( 0x406F <= exp ) { + if ( (exp == 0x7FFF) && (fracF128UI64( uiA64 ) | uiA0) ) { + uiZ = softfloat_propagateNaNF128UI( uiA64, uiA0, 0, 0 ); + goto uiZ; + } + return a; + } + /*-------------------------------------------------------------------- + *--------------------------------------------------------------------*/ + lastBitMask = (uint_fast64_t) 2<<(0x406E - exp); + roundBitsMask = lastBitMask - 1; + uiZ.v64 = uiA64; + uiZ.v0 = uiA0; + roundNearEven = (roundingMode == softfloat_round_near_even); + if ( roundNearEven || (roundingMode == softfloat_round_near_maxMag) ) { + if ( exp == 0x402F ) { + if ( UINT64_C( 0x8000000000000000 ) <= uiZ.v0 ) { + ++uiZ.v64; + if ( + roundNearEven + && (uiZ.v0 == UINT64_C( 0x8000000000000000 )) + ) { + uiZ.v64 &= ~1; + } + } + } else { + uiZ = softfloat_add128( uiZ.v64, uiZ.v0, 0, lastBitMask>>1 ); + if ( roundNearEven && ! (uiZ.v0 & roundBitsMask) ) { + uiZ.v0 &= ~lastBitMask; + } + } + } else if ( roundingMode != softfloat_round_minMag ) { + if ( + signF128UI64( uiZ.v64 ) ^ (roundingMode == softfloat_round_max) + ) { + uiZ = softfloat_add128( uiZ.v64, uiZ.v0, 0, roundBitsMask ); + } + } + uiZ.v0 &= ~roundBitsMask; + } else { + /*-------------------------------------------------------------------- + *--------------------------------------------------------------------*/ + if ( exp < 0x3FFF ) { + if ( ! ((uiA64 & UINT64_C( 0x7FFFFFFFFFFFFFFF )) | uiA0) ) { + return a; + } + if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact; + uiZ.v64 = uiA64 & packToF128UI64( 1, 0, 0 ); + uiZ.v0 = 0; + switch ( roundingMode ) { + case softfloat_round_near_even: + if ( ! (fracF128UI64( uiA64 ) | uiA0) ) break; + case softfloat_round_near_maxMag: + if ( exp == 0x3FFE ) uiZ.v64 |= packToF128UI64( 0, 0x3FFF, 0 ); + break; + case softfloat_round_min: + if ( uiZ.v64 ) uiZ.v64 = packToF128UI64( 1, 0x3FFF, 0 ); + break; + case softfloat_round_max: + if ( ! uiZ.v64 ) uiZ.v64 = packToF128UI64( 0, 0x3FFF, 0 ); + break; + } + goto uiZ; + } + /*-------------------------------------------------------------------- + *--------------------------------------------------------------------*/ + uiZ.v64 = uiA64; + uiZ.v0 = 0; + lastBitMask = (uint_fast64_t) 1<<(0x402F - exp); + roundBitsMask = lastBitMask - 1; + if ( roundingMode == softfloat_round_near_maxMag ) { + uiZ.v64 += lastBitMask>>1; + } else if ( roundingMode == softfloat_round_near_even ) { + uiZ.v64 += lastBitMask>>1; + if ( ! ((uiZ.v64 & roundBitsMask) | uiA0) ) { + uiZ.v64 &= ~lastBitMask; + } + } else if ( roundingMode != softfloat_round_minMag ) { + if ( + signF128UI64( uiZ.v64 ) ^ (roundingMode == softfloat_round_max) + ) { + uiZ.v64 = (uiZ.v64 | (uiA0 != 0)) + roundBitsMask; + } + } + uiZ.v64 &= ~roundBitsMask; + } + if ( exact && ((uiZ.v64 != uiA64) || (uiZ.v0 != uiA0)) ) { + softfloat_exceptionFlags |= softfloat_flag_inexact; + } + uiZ: + uZ.ui = uiZ; + return uZ.f; + +} + |