Eyck Jentzsch
dcaf5467e8
(http://www.jhauser.us/arithmetic/SoftFloat.html) with RISCV specialization and cmake build
104 lines
4.0 KiB
C
104 lines
4.0 KiB
C
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/*============================================================================
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This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
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Package, Release 3e, by John R. Hauser.
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Copyright 2011, 2012, 2013, 2014, 2015, 2016, 2017 The Regents of the
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University of California. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright notice,
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this list of conditions, and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions, and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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3. Neither the name of the University nor the names of its contributors may
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be used to endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
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DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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=============================================================================*/
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#include <stdbool.h>
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#include <stdint.h>
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#include "platform.h"
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#include "internals.h"
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#include "specialize.h"
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#include "softfloat.h"
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uint_fast64_t f64_to_ui64( float64_t a, uint_fast8_t roundingMode, bool exact )
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{
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union ui64_f64 uA;
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uint_fast64_t uiA;
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bool sign;
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int_fast16_t exp;
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uint_fast64_t sig;
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int_fast16_t shiftDist;
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#ifdef SOFTFLOAT_FAST_INT64
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struct uint64_extra sigExtra;
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#else
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uint32_t extSig[3];
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#endif
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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uA.f = a;
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uiA = uA.ui;
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sign = signF64UI( uiA );
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exp = expF64UI( uiA );
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sig = fracF64UI( uiA );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( exp ) sig |= UINT64_C( 0x0010000000000000 );
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shiftDist = 0x433 - exp;
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#ifdef SOFTFLOAT_FAST_INT64
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if ( shiftDist <= 0 ) {
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if ( shiftDist < -11 ) goto invalid;
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sigExtra.v = sig<<-shiftDist;
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sigExtra.extra = 0;
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} else {
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sigExtra = softfloat_shiftRightJam64Extra( sig, 0, shiftDist );
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}
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return
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softfloat_roundToUI64(
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sign, sigExtra.v, sigExtra.extra, roundingMode, exact );
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#else
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extSig[indexWord( 3, 0 )] = 0;
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if ( shiftDist <= 0 ) {
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if ( shiftDist < -11 ) goto invalid;
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sig <<= -shiftDist;
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extSig[indexWord( 3, 2 )] = sig>>32;
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extSig[indexWord( 3, 1 )] = sig;
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} else {
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extSig[indexWord( 3, 2 )] = sig>>32;
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extSig[indexWord( 3, 1 )] = sig;
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softfloat_shiftRightJam96M( extSig, shiftDist, extSig );
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}
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return softfloat_roundMToUI64( sign, extSig, roundingMode, exact );
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#endif
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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invalid:
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softfloat_raiseFlags( softfloat_flag_invalid );
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return
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(exp == 0x7FF) && fracF64UI( uiA ) ? ui64_fromNaN
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: sign ? ui64_fromNegOverflow : ui64_fromPosOverflow;
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}
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