diff options
Diffstat (limited to 'softfloat/f64_roundToInt.c')
| -rw-r--r--[-rwxr-xr-x] | softfloat/f64_roundToInt.c | 113 |
1 files changed, 72 insertions, 41 deletions
diff --git a/softfloat/f64_roundToInt.c b/softfloat/f64_roundToInt.c index ef16dfa..94fe40d 100755..100644 --- a/softfloat/f64_roundToInt.c +++ b/softfloat/f64_roundToInt.c @@ -1,4 +1,39 @@ +/*============================================================================ + +This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic +Package, Release 3a, 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 <stdbool.h> #include <stdint.h> #include "platform.h" @@ -6,70 +41,66 @@ #include "specialize.h" #include "softfloat.h" -float64_t f64_roundToInt( float64_t a, int_fast8_t roundingMode, bool exact ) +float64_t f64_roundToInt( float64_t a, uint_fast8_t roundingMode, bool exact ) { union ui64_f64 uA; uint_fast64_t uiA; - int_fast16_t expA; - uint_fast64_t uiZ; - bool signA; - uint_fast64_t lastBitMask, roundBitsMask; + int_fast16_t exp; + uint_fast64_t uiZ, lastBitMask, roundBitsMask; union ui64_f64 uZ; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ uA.f = a; uiA = uA.ui; - expA = expF64UI( uiA ); - if ( 0x433 <= expA ) { - if ( ( expA == 0x7FF ) && fracF64UI( uiA ) ) { - uiZ = softfloat_propagateNaNF64UI( uiA, 0 ); - goto uiZ; - } - return a; - } - if ( expA <= 0x3FE ) { - if ( ! ( uiA & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) ) return a; + exp = expF64UI( uiA ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( exp <= 0x3FE ) { + if ( ! (uiA & UINT64_C( 0x7FFFFFFFFFFFFFFF )) ) return a; if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact; - signA = signF64UI( uiA ); + uiZ = uiA & packToF64UI( 1, 0, 0 ); switch ( roundingMode ) { - case softfloat_round_nearest_even: - if ( ( expA == 0x3FE ) && fracF64UI( uiA ) ) { - uiZ = packToF64UI( signA, 0x3FF, 0 ); - goto uiZ; - } + case softfloat_round_near_even: + if ( ! fracF64UI( uiA ) ) break; + case softfloat_round_near_maxMag: + if ( exp == 0x3FE ) uiZ |= packToF64UI( 0, 0x3FF, 0 ); break; case softfloat_round_min: - uiZ = signA ? UINT64_C( 0xBFF0000000000000 ) : 0; - goto uiZ; + if ( uiZ ) uiZ = packToF64UI( 1, 0x3FF, 0 ); + break; case softfloat_round_max: - uiZ = - signA ? UINT64_C( 0x8000000000000000 ) - : UINT64_C( 0x3FF0000000000000 ); - goto uiZ; - case softfloat_round_nearest_maxMag: - if ( expA == 0x3FE ) { - uiZ = packToF64UI( signA, 0x3FF, 0 ); - goto uiZ; - } + if ( ! uiZ ) uiZ = packToF64UI( 0, 0x3FF, 0 ); break; } - uiZ = packToF64UI( signA, 0, 0 ); goto uiZ; } - lastBitMask = (uint_fast64_t) 1<<( 0x433 - expA ); - roundBitsMask = lastBitMask - 1; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( 0x433 <= exp ) { + if ( (exp == 0x7FF) && fracF64UI( uiA ) ) { + uiZ = softfloat_propagateNaNF64UI( uiA, 0 ); + goto uiZ; + } + return a; + } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ uiZ = uiA; - if ( roundingMode == softfloat_round_nearest_maxMag ) { + lastBitMask = (uint_fast64_t) 1<<(0x433 - 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; + if ( ! (uiZ & roundBitsMask) ) uiZ &= ~lastBitMask; } else if ( roundingMode != softfloat_round_minMag ) { - if ( signF64UI( uiZ ) ^ ( roundingMode == softfloat_round_max ) ) { + if ( signF64UI( uiZ ) ^ (roundingMode == softfloat_round_max) ) { uiZ += roundBitsMask; } } - uiZ &= ~ roundBitsMask; - if ( exact && ( uiZ != uiA ) ) { + uiZ &= ~roundBitsMask; + if ( exact && (uiZ != uiA) ) { softfloat_exceptionFlags |= softfloat_flag_inexact; } uiZ: |