| |
| /*============================================================================ |
| |
| This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic |
| Package, Release 3d, by John R. Hauser. |
| |
| Copyright 2011, 2012, 2013, 2014, 2015, 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 "softfloat.h" |
| |
| extFloat80_t |
| softfloat_roundPackToExtF80( |
| bool sign, |
| int_fast32_t exp, |
| uint_fast64_t sig, |
| uint_fast64_t sigExtra, |
| uint_fast8_t roundingPrecision |
| ) |
| { |
| uint_fast8_t roundingMode; |
| bool roundNearEven; |
| uint_fast64_t roundIncrement, roundMask, roundBits; |
| bool isTiny, doIncrement; |
| struct uint64_extra sig64Extra; |
| union { struct extFloat80M s; extFloat80_t f; } uZ; |
| |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| roundingMode = softfloat_roundingMode; |
| roundNearEven = (roundingMode == softfloat_round_near_even); |
| if ( roundingPrecision == 80 ) goto precision80; |
| if ( roundingPrecision == 64 ) { |
| roundIncrement = UINT64_C( 0x0000000000000400 ); |
| roundMask = UINT64_C( 0x00000000000007FF ); |
| } else if ( roundingPrecision == 32 ) { |
| roundIncrement = UINT64_C( 0x0000008000000000 ); |
| roundMask = UINT64_C( 0x000000FFFFFFFFFF ); |
| } else { |
| goto precision80; |
| } |
| sig |= (sigExtra != 0); |
| if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) { |
| roundIncrement = |
| (roundingMode |
| == (sign ? softfloat_round_min : softfloat_round_max)) |
| ? roundMask |
| : 0; |
| } |
| roundBits = sig & roundMask; |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| if ( 0x7FFD <= (uint32_t) (exp - 1) ) { |
| if ( exp <= 0 ) { |
| /*---------------------------------------------------------------- |
| *----------------------------------------------------------------*/ |
| isTiny = |
| (softfloat_detectTininess |
| == softfloat_tininess_beforeRounding) |
| || (exp < 0) |
| || (sig <= (uint64_t) (sig + roundIncrement)); |
| sig = softfloat_shiftRightJam64( sig, 1 - exp ); |
| roundBits = sig & roundMask; |
| if ( roundBits ) { |
| if ( isTiny ) softfloat_raiseFlags( softfloat_flag_underflow ); |
| softfloat_exceptionFlags |= softfloat_flag_inexact; |
| #ifdef SOFTFLOAT_ROUND_ODD |
| if ( roundingMode == softfloat_round_odd ) { |
| sig |= roundMask + 1; |
| } |
| #endif |
| } |
| sig += roundIncrement; |
| exp = ((sig & UINT64_C( 0x8000000000000000 )) != 0); |
| roundIncrement = roundMask + 1; |
| if ( roundNearEven && (roundBits<<1 == roundIncrement) ) { |
| roundMask |= roundIncrement; |
| } |
| sig &= ~roundMask; |
| goto packReturn; |
| } |
| if ( |
| (0x7FFE < exp) |
| || ((exp == 0x7FFE) && ((uint64_t) (sig + roundIncrement) < sig)) |
| ) { |
| goto overflow; |
| } |
| } |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| if ( roundBits ) { |
| softfloat_exceptionFlags |= softfloat_flag_inexact; |
| #ifdef SOFTFLOAT_ROUND_ODD |
| if ( roundingMode == softfloat_round_odd ) { |
| sig = (sig & ~roundMask) | (roundMask + 1); |
| goto packReturn; |
| } |
| #endif |
| } |
| sig = (uint64_t) (sig + roundIncrement); |
| if ( sig < roundIncrement ) { |
| ++exp; |
| sig = UINT64_C( 0x8000000000000000 ); |
| } |
| roundIncrement = roundMask + 1; |
| if ( roundNearEven && (roundBits<<1 == roundIncrement) ) { |
| roundMask |= roundIncrement; |
| } |
| sig &= ~roundMask; |
| goto packReturn; |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| precision80: |
| doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra); |
| if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) { |
| doIncrement = |
| (roundingMode |
| == (sign ? softfloat_round_min : softfloat_round_max)) |
| && sigExtra; |
| } |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| if ( 0x7FFD <= (uint32_t) (exp - 1) ) { |
| if ( exp <= 0 ) { |
| /*---------------------------------------------------------------- |
| *----------------------------------------------------------------*/ |
| isTiny = |
| (softfloat_detectTininess |
| == softfloat_tininess_beforeRounding) |
| || (exp < 0) |
| || ! doIncrement |
| || (sig < UINT64_C( 0xFFFFFFFFFFFFFFFF )); |
| sig64Extra = |
| softfloat_shiftRightJam64Extra( sig, sigExtra, 1 - exp ); |
| exp = 0; |
| sig = sig64Extra.v; |
| sigExtra = sig64Extra.extra; |
| if ( sigExtra ) { |
| if ( isTiny ) softfloat_raiseFlags( softfloat_flag_underflow ); |
| softfloat_exceptionFlags |= softfloat_flag_inexact; |
| #ifdef SOFTFLOAT_ROUND_ODD |
| if ( roundingMode == softfloat_round_odd ) { |
| sig |= 1; |
| goto packReturn; |
| } |
| #endif |
| } |
| doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra); |
| if ( |
| ! roundNearEven |
| && (roundingMode != softfloat_round_near_maxMag) |
| ) { |
| doIncrement = |
| (roundingMode |
| == (sign ? softfloat_round_min : softfloat_round_max)) |
| && sigExtra; |
| } |
| if ( doIncrement ) { |
| ++sig; |
| sig &= |
| ~(uint_fast64_t) |
| (! (sigExtra & UINT64_C( 0x7FFFFFFFFFFFFFFF )) |
| & roundNearEven); |
| exp = ((sig & UINT64_C( 0x8000000000000000 )) != 0); |
| } |
| goto packReturn; |
| } |
| if ( |
| (0x7FFE < exp) |
| || ((exp == 0x7FFE) && (sig == UINT64_C( 0xFFFFFFFFFFFFFFFF )) |
| && doIncrement) |
| ) { |
| /*---------------------------------------------------------------- |
| *----------------------------------------------------------------*/ |
| roundMask = 0; |
| overflow: |
| softfloat_raiseFlags( |
| softfloat_flag_overflow | softfloat_flag_inexact ); |
| if ( |
| roundNearEven |
| || (roundingMode == softfloat_round_near_maxMag) |
| || (roundingMode |
| == (sign ? softfloat_round_min : softfloat_round_max)) |
| ) { |
| exp = 0x7FFF; |
| sig = UINT64_C( 0x8000000000000000 ); |
| } else { |
| exp = 0x7FFE; |
| sig = ~roundMask; |
| } |
| goto packReturn; |
| } |
| } |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| if ( sigExtra ) { |
| softfloat_exceptionFlags |= softfloat_flag_inexact; |
| #ifdef SOFTFLOAT_ROUND_ODD |
| if ( roundingMode == softfloat_round_odd ) { |
| sig |= 1; |
| goto packReturn; |
| } |
| #endif |
| } |
| if ( doIncrement ) { |
| ++sig; |
| if ( ! sig ) { |
| ++exp; |
| sig = UINT64_C( 0x8000000000000000 ); |
| } else { |
| sig &= |
| ~(uint_fast64_t) |
| (! (sigExtra & UINT64_C( 0x7FFFFFFFFFFFFFFF )) |
| & roundNearEven); |
| } |
| } |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| packReturn: |
| uZ.s.signExp = packToExtF80UI64( sign, exp ); |
| uZ.s.signif = sig; |
| return uZ.f; |
| |
| } |
| |
