| // SPDX-License-Identifier: BSD-3-Clause |
| |
| /*============================================================================ |
| |
| 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" |
| #include "internals.h" |
| #include "specialize.h" |
| #include "softfloat.h" |
| |
| float128_t f128_rem( float128_t a, float128_t b ) |
| { |
| union ui128_f128 uA; |
| uint_fast64_t uiA64, uiA0; |
| bool signA; |
| int_fast32_t expA; |
| struct uint128 sigA; |
| union ui128_f128 uB; |
| uint_fast64_t uiB64, uiB0; |
| bool signB; |
| int_fast32_t expB; |
| struct uint128 sigB; |
| struct exp32_sig128 normExpSig; |
| struct uint128 rem; |
| int_fast32_t expDiff; |
| uint_fast32_t q, recip32; |
| uint_fast64_t q64; |
| struct uint128 term, altRem, meanRem; |
| bool signRem; |
| struct uint128 uiZ; |
| union ui128_f128 uZ; |
| |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| uA.f = a; |
| uiA64 = uA.ui.v64; |
| uiA0 = uA.ui.v0; |
| signA = signF128UI64( uiA64 ); |
| expA = expF128UI64( uiA64 ); |
| sigA.v64 = fracF128UI64( uiA64 ); |
| sigA.v0 = uiA0; |
| uB.f = b; |
| uiB64 = uB.ui.v64; |
| uiB0 = uB.ui.v0; |
| signB = signF128UI64( uiB64 ); |
| expB = expF128UI64( uiB64 ); |
| sigB.v64 = fracF128UI64( uiB64 ); |
| sigB.v0 = uiB0; |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| if ( expA == 0x7FFF ) { |
| if ( |
| (sigA.v64 | sigA.v0) || ((expB == 0x7FFF) && (sigB.v64 | sigB.v0)) |
| ) { |
| goto propagateNaN; |
| } |
| goto invalid; |
| } |
| if ( expB == 0x7FFF ) { |
| if ( sigB.v64 | sigB.v0 ) goto propagateNaN; |
| return a; |
| } |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| if ( ! expB ) { |
| if ( ! (sigB.v64 | sigB.v0) ) goto invalid; |
| normExpSig = softfloat_normSubnormalF128Sig( sigB.v64, sigB.v0 ); |
| expB = normExpSig.exp; |
| sigB = normExpSig.sig; |
| } |
| if ( ! expA ) { |
| if ( ! (sigA.v64 | sigA.v0) ) return a; |
| normExpSig = softfloat_normSubnormalF128Sig( sigA.v64, sigA.v0 ); |
| expA = normExpSig.exp; |
| sigA = normExpSig.sig; |
| } |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| sigA.v64 |= UINT64_C( 0x0001000000000000 ); |
| sigB.v64 |= UINT64_C( 0x0001000000000000 ); |
| rem = sigA; |
| expDiff = expA - expB; |
| if ( expDiff < 1 ) { |
| if ( expDiff < -1 ) return a; |
| if ( expDiff ) { |
| --expB; |
| sigB = softfloat_add128( sigB.v64, sigB.v0, sigB.v64, sigB.v0 ); |
| q = 0; |
| } else { |
| q = softfloat_le128( sigB.v64, sigB.v0, rem.v64, rem.v0 ); |
| if ( q ) { |
| rem = softfloat_sub128( rem.v64, rem.v0, sigB.v64, sigB.v0 ); |
| } |
| } |
| } else { |
| recip32 = softfloat_approxRecip32_1( sigB.v64>>17 ); |
| expDiff -= 30; |
| for (;;) { |
| q64 = (uint_fast64_t) (uint32_t) (rem.v64>>19) * recip32; |
| if ( expDiff < 0 ) break; |
| q = (q64 + 0x80000000)>>32; |
| rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, 29 ); |
| term = softfloat_mul128By32( sigB.v64, sigB.v0, q ); |
| rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 ); |
| if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) { |
| rem = softfloat_add128( rem.v64, rem.v0, sigB.v64, sigB.v0 ); |
| } |
| expDiff -= 29; |
| } |
| /*-------------------------------------------------------------------- |
| | (`expDiff' cannot be less than -29 here.) |
| *--------------------------------------------------------------------*/ |
| q = (uint32_t) (q64>>32)>>(~expDiff & 31); |
| rem = softfloat_shortShiftLeft128( rem.v64, rem.v0, expDiff + 30 ); |
| term = softfloat_mul128By32( sigB.v64, sigB.v0, q ); |
| rem = softfloat_sub128( rem.v64, rem.v0, term.v64, term.v0 ); |
| if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) { |
| altRem = softfloat_add128( rem.v64, rem.v0, sigB.v64, sigB.v0 ); |
| goto selectRem; |
| } |
| } |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| do { |
| altRem = rem; |
| ++q; |
| rem = softfloat_sub128( rem.v64, rem.v0, sigB.v64, sigB.v0 ); |
| } while ( ! (rem.v64 & UINT64_C( 0x8000000000000000 )) ); |
| selectRem: |
| meanRem = softfloat_add128( rem.v64, rem.v0, altRem.v64, altRem.v0 ); |
| if ( |
| (meanRem.v64 & UINT64_C( 0x8000000000000000 )) |
| || (! (meanRem.v64 | meanRem.v0) && (q & 1)) |
| ) { |
| rem = altRem; |
| } |
| signRem = signA; |
| if ( rem.v64 & UINT64_C( 0x8000000000000000 ) ) { |
| signRem = ! signRem; |
| rem = softfloat_sub128( 0, 0, rem.v64, rem.v0 ); |
| } |
| return softfloat_normRoundPackToF128( signRem, expB - 1, rem.v64, rem.v0 ); |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| propagateNaN: |
| uiZ = softfloat_propagateNaNF128UI( uiA64, uiA0, uiB64, uiB0 ); |
| goto uiZ; |
| /*------------------------------------------------------------------------ |
| *------------------------------------------------------------------------*/ |
| invalid: |
| softfloat_raiseFlags( softfloat_flag_invalid ); |
| uiZ.v64 = defaultNaNF128UI64; |
| uiZ.v0 = defaultNaNF128UI0; |
| uiZ: |
| uZ.ui = uiZ; |
| return uZ.f; |
| |
| } |
| |
