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Diffstat (limited to 'softfloat/f128_roundToInt.c')
| -rw-r--r-- | softfloat/f128_roundToInt.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/softfloat/f128_roundToInt.c b/softfloat/f128_roundToInt.c new file mode 100644 index 0000000..8ae084b --- /dev/null +++ b/softfloat/f128_roundToInt.c @@ -0,0 +1,172 @@ + +/*============================================================================ + +This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic +Package, Release 3e, by John R. Hauser. + +Copyright 2011, 2012, 2013, 2014, 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 <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 lastBitMask0, roundBitsMask; + bool roundNearEven; + uint_fast64_t lastBitMask64; + 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; + } + /*-------------------------------------------------------------------- + *--------------------------------------------------------------------*/ + lastBitMask0 = (uint_fast64_t) 2<<(0x406E - exp); + roundBitsMask = lastBitMask0 - 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, lastBitMask0>>1 ); + if ( roundNearEven && !(uiZ.v0 & roundBitsMask) ) { + uiZ.v0 &= ~lastBitMask0; + } + } + } else if ( + roundingMode + == (signF128UI64( uiZ.v64 ) ? softfloat_round_min + : softfloat_round_max) + ) { + uiZ = softfloat_add128( uiZ.v64, uiZ.v0, 0, roundBitsMask ); + } + uiZ.v0 &= ~roundBitsMask; + lastBitMask64 = !lastBitMask0; + } else { + /*-------------------------------------------------------------------- + *--------------------------------------------------------------------*/ + if ( exp < 0x3FFF ) { + if ( !((uiA64 & UINT64_C( 0x7FFFFFFFFFFFFFFF )) | uiA0) ) return a; + if ( exact ) softfloat_raiseFlags( 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; +#ifdef SOFTFLOAT_ROUND_ODD + case softfloat_round_odd: + uiZ.v64 |= packToF128UI64( 0, 0x3FFF, 0 ); + break; +#endif + } + goto uiZ; + } + /*-------------------------------------------------------------------- + *--------------------------------------------------------------------*/ + uiZ.v64 = uiA64; + uiZ.v0 = 0; + lastBitMask64 = (uint_fast64_t) 1<<(0x402F - exp); + roundBitsMask = lastBitMask64 - 1; + if ( roundingMode == softfloat_round_near_maxMag ) { + uiZ.v64 += lastBitMask64>>1; + } else if ( roundingMode == softfloat_round_near_even ) { + uiZ.v64 += lastBitMask64>>1; + if ( !((uiZ.v64 & roundBitsMask) | uiA0) ) { + uiZ.v64 &= ~lastBitMask64; + } + } else if ( + roundingMode + == (signF128UI64( uiZ.v64 ) ? softfloat_round_min + : softfloat_round_max) + ) { + uiZ.v64 = (uiZ.v64 | (uiA0 != 0)) + roundBitsMask; + } + uiZ.v64 &= ~roundBitsMask; + lastBitMask0 = 0; + } + if ( (uiZ.v64 != uiA64) || (uiZ.v0 != uiA0) ) { +#ifdef SOFTFLOAT_ROUND_ODD + if ( roundingMode == softfloat_round_odd ) { + uiZ.v64 |= lastBitMask64; + uiZ.v0 |= lastBitMask0; + } +#endif + if ( exact ) softfloat_raiseFlags( softfloat_flag_inexact ); + } + uiZ: + uZ.ui = uiZ; + return uZ.f; + +} + |