| // 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" |
| |
| float64_t |
| softfloat_subMagsF64( uint_fast64_t uiA, uint_fast64_t uiB, bool signZ ) |
| { |
| int_fast16_t expA; |
| uint_fast64_t sigA; |
| int_fast16_t expB; |
| uint_fast64_t sigB; |
| int_fast16_t expDiff; |
| uint_fast64_t uiZ; |
| int_fast16_t expZ; |
| uint_fast64_t sigZ; |
| union ui64_f64 uZ; |
| |
| expA = expF64UI( uiA ); |
| sigA = fracF64UI( uiA ); |
| expB = expF64UI( uiB ); |
| sigB = fracF64UI( uiB ); |
| expDiff = expA - expB; |
| sigA <<= 10; |
| sigB <<= 10; |
| if ( 0 < expDiff ) goto expABigger; |
| if ( expDiff < 0 ) goto expBBigger; |
| if ( expA == 0x7FF ) { |
| if ( sigA | sigB ) goto propagateNaN; |
| softfloat_raiseFlags( softfloat_flag_invalid ); |
| uiZ = defaultNaNF64UI; |
| goto uiZ; |
| } |
| if ( ! expA ) { |
| expA = 1; |
| expB = 1; |
| } |
| if ( sigB < sigA ) goto aBigger; |
| if ( sigA < sigB ) goto bBigger; |
| uiZ = packToF64UI( softfloat_roundingMode == softfloat_round_min, 0, 0 ); |
| goto uiZ; |
| expBBigger: |
| if ( expB == 0x7FF ) { |
| if ( sigB ) goto propagateNaN; |
| uiZ = packToF64UI( signZ ^ 1, 0x7FF, 0 ); |
| goto uiZ; |
| } |
| sigA += expA ? UINT64_C( 0x4000000000000000 ) : sigA; |
| sigA = softfloat_shiftRightJam64( sigA, -expDiff ); |
| sigB |= UINT64_C( 0x4000000000000000 ); |
| bBigger: |
| signZ ^= 1; |
| expZ = expB; |
| sigZ = sigB - sigA; |
| goto normRoundPack; |
| expABigger: |
| if ( expA == 0x7FF ) { |
| if ( sigA ) goto propagateNaN; |
| uiZ = uiA; |
| goto uiZ; |
| } |
| sigB += expB ? UINT64_C( 0x4000000000000000 ) : sigB; |
| sigB = softfloat_shiftRightJam64( sigB, expDiff ); |
| sigA |= UINT64_C( 0x4000000000000000 ); |
| aBigger: |
| expZ = expA; |
| sigZ = sigA - sigB; |
| normRoundPack: |
| return softfloat_normRoundPackToF64( signZ, expZ - 1, sigZ ); |
| propagateNaN: |
| uiZ = softfloat_propagateNaNF64UI( uiA, uiB ); |
| uiZ: |
| uZ.ui = uiZ; |
| return uZ.f; |
| |
| } |
| |