| |
| /*============================================================================ |
| |
| 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; |
| |
| } |
| |