| |
| /*============================================================================ |
| |
| 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" |
| |
| float32_t |
| softfloat_subMagsF32( uint_fast32_t uiA, uint_fast32_t uiB, bool signZ ) |
| { |
| int_fast16_t expA; |
| uint_fast32_t sigA; |
| int_fast16_t expB; |
| uint_fast32_t sigB; |
| int_fast16_t expDiff; |
| uint_fast32_t uiZ; |
| int_fast16_t expZ; |
| uint_fast32_t sigZ; |
| union ui32_f32 uZ; |
| |
| expA = expF32UI( uiA ); |
| sigA = fracF32UI( uiA ); |
| expB = expF32UI( uiB ); |
| sigB = fracF32UI( uiB ); |
| expDiff = expA - expB; |
| sigA <<= 7; |
| sigB <<= 7; |
| if ( 0 < expDiff ) goto expABigger; |
| if ( expDiff < 0 ) goto expBBigger; |
| if ( expA == 0xFF ) { |
| if ( sigA | sigB ) goto propagateNaN; |
| softfloat_raiseFlags( softfloat_flag_invalid ); |
| uiZ = defaultNaNF32UI; |
| goto uiZ; |
| } |
| if ( ! expA ) { |
| expA = 1; |
| expB = 1; |
| } |
| if ( sigB < sigA ) goto aBigger; |
| if ( sigA < sigB ) goto bBigger; |
| uiZ = packToF32UI( softfloat_roundingMode == softfloat_round_min, 0, 0 ); |
| goto uiZ; |
| expBBigger: |
| if ( expB == 0xFF ) { |
| if ( sigB ) goto propagateNaN; |
| uiZ = packToF32UI( signZ ^ 1, 0xFF, 0 ); |
| goto uiZ; |
| } |
| sigA += expA ? 0x40000000 : sigA; |
| sigA = softfloat_shiftRightJam32( sigA, -expDiff ); |
| sigB |= 0x40000000; |
| bBigger: |
| signZ ^= 1; |
| expZ = expB; |
| sigZ = sigB - sigA; |
| goto normRoundPack; |
| expABigger: |
| if ( expA == 0xFF ) { |
| if ( sigA ) goto propagateNaN; |
| uiZ = uiA; |
| goto uiZ; |
| } |
| sigB += expB ? 0x40000000 : sigB; |
| sigB = softfloat_shiftRightJam32( sigB, expDiff ); |
| sigA |= 0x40000000; |
| aBigger: |
| expZ = expA; |
| sigZ = sigA - sigB; |
| normRoundPack: |
| return softfloat_normRoundPackToF32( signZ, expZ - 1, sigZ ); |
| propagateNaN: |
| uiZ = softfloat_propagateNaNF32UI( uiA, uiB ); |
| uiZ: |
| uZ.ui = uiZ; |
| return uZ.f; |
| |
| } |
| |