diff options
Diffstat (limited to 'softfloat/f32_roundToInt.c')
| -rw-r--r--[-rwxr-xr-x] | softfloat/f32_roundToInt.c | 128 |
1 files changed, 84 insertions, 44 deletions
diff --git a/softfloat/f32_roundToInt.c b/softfloat/f32_roundToInt.c index 8c0cef9..89a40f3 100755..100644 --- a/softfloat/f32_roundToInt.c +++ b/softfloat/f32_roundToInt.c @@ -1,5 +1,38 @@ -// See LICENSE.SoftFloat for license details. +/*============================================================================ + +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> @@ -8,69 +41,76 @@ #include "specialize.h" #include "softfloat.h" -float32_t f32_roundToInt( float32_t a, int_fast8_t roundingMode, bool exact ) +float32_t f32_roundToInt( float32_t a, uint_fast8_t roundingMode, bool exact ) { union ui32_f32 uA; uint_fast32_t uiA; - int_fast16_t expA; - uint_fast32_t uiZ; - bool signA; - uint_fast32_t lastBitMask, roundBitsMask; + int_fast16_t exp; + uint_fast32_t uiZ, lastBitMask, roundBitsMask; union ui32_f32 uZ; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ uA.f = a; uiA = uA.ui; - expA = expF32UI( uiA ); - if ( 0x96 <= expA ) { - if ( ( expA == 0xFF ) && fracF32UI( uiA ) ) { - uiZ = softfloat_propagateNaNF32UI( uiA, 0 ); - goto uiZ; - } - return a; - } - if ( expA <= 0x7E ) { - if ( ! (uint32_t) ( uiA<<1 ) ) return a; + exp = expF32UI( uiA ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( exp <= 0x7E ) { + if ( !(uint32_t) (uiA<<1) ) return a; if ( exact ) softfloat_raiseFlags( softfloat_flag_inexact ); - signA = signF32UI( uiA ); + uiZ = uiA & packToF32UI( 1, 0, 0 ); switch ( roundingMode ) { - case softfloat_round_nearest_even: - if ( ( expA == 0x7E ) && fracF32UI( uiA ) ) { - uiZ = packToF32UI( signA, 0x7F, 0 ); - goto uiZ; - } + case softfloat_round_near_even: + if ( !fracF32UI( uiA ) ) break; + case softfloat_round_near_maxMag: + if ( exp == 0x7E ) uiZ |= packToF32UI( 0, 0x7F, 0 ); break; case softfloat_round_min: - uiZ = signA ? 0xBF800000 : 0; - goto uiZ; + if ( uiZ ) uiZ = packToF32UI( 1, 0x7F, 0 ); + break; case softfloat_round_max: - uiZ = signA ? 0x80000000 : 0x3F800000; - goto uiZ; - case softfloat_round_nearest_maxMag: - if ( expA == 0x7E ) { - uiZ = packToF32UI( signA, 0x7F, 0 ); - goto uiZ; - } + if ( !uiZ ) uiZ = packToF32UI( 0, 0x7F, 0 ); + break; +#ifdef SOFTFLOAT_ROUND_ODD + case softfloat_round_odd: + uiZ |= packToF32UI( 0, 0x7F, 0 ); break; +#endif } - uiZ = packToF32UI( signA, 0, 0 ); goto uiZ; } - lastBitMask = (uint_fast32_t) 1<<( 0x96 - expA ); - roundBitsMask = lastBitMask - 1; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( 0x96 <= exp ) { + if ( (exp == 0xFF) && fracF32UI( uiA ) ) { + uiZ = softfloat_propagateNaNF32UI( uiA, 0 ); + goto uiZ; + } + return a; + } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ uiZ = uiA; - if ( roundingMode == softfloat_round_nearest_maxMag ) { + lastBitMask = (uint_fast32_t) 1<<(0x96 - exp); + roundBitsMask = lastBitMask - 1; + if ( roundingMode == softfloat_round_near_maxMag ) { uiZ += lastBitMask>>1; - } else if ( roundingMode == softfloat_round_nearest_even ) { + } else if ( roundingMode == softfloat_round_near_even ) { uiZ += lastBitMask>>1; - if ( ! ( uiZ & roundBitsMask ) ) uiZ &= ~ lastBitMask; - } else if ( roundingMode != softfloat_round_minMag ) { - if ( signF32UI( uiZ ) ^ ( roundingMode == softfloat_round_max ) ) { - uiZ += roundBitsMask; - } + if ( !(uiZ & roundBitsMask) ) uiZ &= ~lastBitMask; + } else if ( + roundingMode + == (signF32UI( uiZ ) ? softfloat_round_min : softfloat_round_max) + ) { + uiZ += roundBitsMask; } - uiZ &= ~ roundBitsMask; - if ( exact && ( uiZ != uiA ) ) { - softfloat_raiseFlags( softfloat_flag_inexact ); + uiZ &= ~roundBitsMask; + if ( uiZ != uiA ) { +#ifdef SOFTFLOAT_ROUND_ODD + if ( roundingMode == softfloat_round_odd ) uiZ |= lastBitMask; +#endif + if ( exact ) softfloat_raiseFlags( softfloat_flag_inexact ); } uiZ: uZ.ui = uiZ; |