| |
| /*============================================================================ |
| |
| 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" |
| |
| extFloat80_t |
| extF80_roundToInt( extFloat80_t a, uint_fast8_t roundingMode, bool exact ) |
| { |
| union { struct extFloat80M s; extFloat80_t f; } uA; |
| uint_fast16_t uiA64, signUI64; |
| int_fast32_t exp; |
| uint_fast64_t sigA; |
| uint_fast16_t uiZ64; |
| uint_fast64_t sigZ; |
| struct exp32_sig64 normExpSig; |
| struct uint128 uiZ; |
| uint_fast64_t lastBitMask, roundBitsMask; |
| union { struct extFloat80M s; extFloat80_t f; } uZ; |
| |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| uA.f = a; |
| uiA64 = uA.s.signExp; |
| signUI64 = uiA64 & packToExtF80UI64( 1, 0 ); |
| exp = expExtF80UI64( uiA64 ); |
| sigA = uA.s.signif; |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| if ( ! (sigA & UINT64_C( 0x8000000000000000 )) && (exp != 0x7FFF) ) { |
| if ( ! sigA ) { |
| uiZ64 = signUI64; |
| sigZ = 0; |
| goto uiZ; |
| } |
| normExpSig = softfloat_normSubnormalExtF80Sig( sigA ); |
| exp += normExpSig.exp; |
| sigA = normExpSig.sig; |
| } |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| if ( 0x403E <= exp ) { |
| if ( exp == 0x7FFF ) { |
| if ( sigA & UINT64_C( 0x7FFFFFFFFFFFFFFF ) ) { |
| uiZ = softfloat_propagateNaNExtF80UI( uiA64, sigA, 0, 0 ); |
| uiZ64 = uiZ.v64; |
| sigZ = uiZ.v0; |
| goto uiZ; |
| } |
| sigZ = UINT64_C( 0x8000000000000000 ); |
| } else { |
| sigZ = sigA; |
| } |
| uiZ64 = signUI64 | exp; |
| goto uiZ; |
| } |
| if ( exp <= 0x3FFE ) { |
| if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact; |
| switch ( roundingMode ) { |
| case softfloat_round_near_even: |
| if ( ! (sigA & UINT64_C( 0x7FFFFFFFFFFFFFFF )) ) break; |
| case softfloat_round_near_maxMag: |
| if ( exp == 0x3FFE ) goto mag1; |
| break; |
| case softfloat_round_min: |
| if ( signUI64 ) goto mag1; |
| break; |
| case softfloat_round_max: |
| if ( ! signUI64 ) goto mag1; |
| break; |
| } |
| uiZ64 = signUI64; |
| sigZ = 0; |
| goto uiZ; |
| mag1: |
| uiZ64 = signUI64 | 0x3FFF; |
| sigZ = UINT64_C( 0x8000000000000000 ); |
| goto uiZ; |
| } |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| uiZ64 = signUI64 | exp; |
| lastBitMask = (uint_fast64_t) 1<<(0x403E - exp); |
| roundBitsMask = lastBitMask - 1; |
| sigZ = sigA; |
| if ( roundingMode == softfloat_round_near_maxMag ) { |
| sigZ += lastBitMask>>1; |
| } else if ( roundingMode == softfloat_round_near_even ) { |
| sigZ += lastBitMask>>1; |
| if ( ! (sigZ & roundBitsMask) ) sigZ &= ~lastBitMask; |
| } else if ( roundingMode != softfloat_round_minMag ) { |
| if ( (signUI64 != 0) ^ (roundingMode == softfloat_round_max) ) { |
| sigZ += roundBitsMask; |
| } |
| } |
| sigZ &= ~roundBitsMask; |
| if ( ! sigZ ) { |
| ++uiZ64; |
| sigZ = UINT64_C( 0x8000000000000000 ); |
| } |
| if ( exact && (sigZ != sigA) ) { |
| softfloat_exceptionFlags |= softfloat_flag_inexact; |
| } |
| uiZ: |
| uZ.s.signExp = uiZ64; |
| uZ.s.signif = sigZ; |
| return uZ.f; |
| |
| } |
| |