99 lines
3.7 KiB
C
99 lines
3.7 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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int_fast32_t
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softfloat_roundToI32(
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bool sign, uint_fast64_t sig, uint_fast8_t roundingMode, bool exact )
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{
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uint_fast16_t roundIncrement, roundBits;
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uint_fast32_t sig32;
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union { uint32_t ui; int32_t i; } uZ;
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int_fast32_t z;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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roundIncrement = 0x800;
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if (
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(roundingMode != softfloat_round_near_maxMag)
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&& (roundingMode != softfloat_round_near_even)
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) {
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roundIncrement = 0;
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if (
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sign
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? (roundingMode == softfloat_round_min)
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#ifdef SOFTFLOAT_ROUND_ODD
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|| (roundingMode == softfloat_round_odd)
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#endif
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: (roundingMode == softfloat_round_max)
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) {
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roundIncrement = 0xFFF;
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}
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}
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roundBits = sig & 0xFFF;
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sig += roundIncrement;
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if ( sig & UINT64_C( 0xFFFFF00000000000 ) ) goto invalid;
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sig32 = sig>>12;
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if (
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(roundBits == 0x800) && (roundingMode == softfloat_round_near_even)
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) {
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sig32 &= ~(uint_fast32_t) 1;
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}
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uZ.ui = sign ? -sig32 : sig32;
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z = uZ.i;
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if ( z && ((z < 0) ^ sign) ) goto invalid;
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if ( roundBits ) {
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#ifdef SOFTFLOAT_ROUND_ODD
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if ( roundingMode == softfloat_round_odd ) z |= 1;
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#endif
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if ( exact ) softfloat_exceptionFlags |= softfloat_flag_inexact;
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}
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return z;
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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 sign ? i32_fromNegOverflow : i32_fromPosOverflow;
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}
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