114 lines
4.8 KiB
C
114 lines
4.8 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 The Regents of the University of
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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_fast64_t f128_to_i64_r_minMag( float128_t a, bool exact )
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{
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union ui128_f128 uA;
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uint_fast64_t uiA64, uiA0;
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bool sign;
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int_fast32_t exp;
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uint_fast64_t sig64, sig0;
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int_fast32_t shiftDist;
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int_fast8_t negShiftDist;
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int_fast64_t absZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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uA.f = a;
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uiA64 = uA.ui.v64;
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uiA0 = uA.ui.v0;
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sign = signF128UI64( uiA64 );
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exp = expF128UI64( uiA64 );
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sig64 = fracF128UI64( uiA64 );
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sig0 = uiA0;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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shiftDist = 0x402F - exp;
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if ( shiftDist < 0 ) {
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/*--------------------------------------------------------------------
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*--------------------------------------------------------------------*/
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if ( shiftDist < -14 ) {
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if (
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(uiA64 == UINT64_C( 0xC03E000000000000 ))
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&& (sig0 < UINT64_C( 0x0002000000000000 ))
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) {
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if ( exact && sig0 ) {
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softfloat_exceptionFlags |= softfloat_flag_inexact;
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}
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return -INT64_C( 0x7FFFFFFFFFFFFFFF ) - 1;
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}
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softfloat_raiseFlags( softfloat_flag_invalid );
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return
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(exp == 0x7FFF) && (sig64 | sig0) ? i64_fromNaN
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: sign ? i64_fromNegOverflow : i64_fromPosOverflow;
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}
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/*--------------------------------------------------------------------
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*--------------------------------------------------------------------*/
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sig64 |= UINT64_C( 0x0001000000000000 );
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negShiftDist = -shiftDist;
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absZ = sig64<<negShiftDist | sig0>>(shiftDist & 63);
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if ( exact && (uint64_t) (sig0<<negShiftDist) ) {
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softfloat_exceptionFlags |= softfloat_flag_inexact;
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}
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} else {
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/*--------------------------------------------------------------------
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*--------------------------------------------------------------------*/
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if ( 49 <= shiftDist ) {
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if ( exact && (exp | sig64 | sig0) ) {
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softfloat_exceptionFlags |= softfloat_flag_inexact;
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}
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return 0;
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}
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/*--------------------------------------------------------------------
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*--------------------------------------------------------------------*/
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sig64 |= UINT64_C( 0x0001000000000000 );
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absZ = sig64>>shiftDist;
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if ( exact && (sig0 || (absZ<<shiftDist != sig64)) ) {
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softfloat_exceptionFlags |= softfloat_flag_inexact;
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}
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}
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return sign ? -absZ : absZ;
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}
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