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77 lines
3.0 KiB
C
77 lines
3.0 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 3, by John R. Hauser.
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Copyright 2011, 2012, 2013, 2014, 2015 The Regents of the University of
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California (Regents). All Rights Reserved. Redistribution and use in source
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and binary forms, with or without modification, are permitted provided that
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the following conditions are met:
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Redistributions of source code must retain the above copyright notice,
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this list of conditions, and the following two paragraphs of disclaimer.
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Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions, and the following two paragraphs of disclaimer in the
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documentation and/or other materials provided with the distribution. Neither
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the name of the Regents nor the names of its contributors may be used to
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endorse or promote products derived from this software without specific prior
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written permission.
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IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
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SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING
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OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF REGENTS HAS
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BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED
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TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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PURPOSE. THE SOFTWARE AND ACCOMPANYING DOCUMENTATION, IF ANY, PROVIDED
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HEREUNDER IS PROVIDED "AS IS". REGENTS HAS NO OBLIGATION TO PROVIDE
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MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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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 "softfloat.h"
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int_fast32_t
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softfloat_roundPackToI32(
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bool sign, uint_fast64_t sig, uint_fast8_t roundingMode, bool exact )
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{
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bool roundNearEven;
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uint_fast8_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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roundNearEven = (roundingMode == softfloat_round_near_even);
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roundIncrement = 0x40;
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if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) {
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roundIncrement =
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(roundingMode
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== (sign ? softfloat_round_min : softfloat_round_max))
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? 0x7F
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: 0;
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}
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roundBits = sig & 0x7F;
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sig += roundIncrement;
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if ( sig & UINT64_C( 0xFFFFFF8000000000 ) ) goto invalid;
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sig32 = sig>>7;
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sig32 &= ~(uint_fast32_t) (! (roundBits ^ 0x40) & roundNearEven);
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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 ( exact && roundBits ) {
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softfloat_exceptionFlags |= softfloat_flag_inexact;
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}
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return z;
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invalid:
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softfloat_raiseFlags( softfloat_flag_invalid );
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return sign ? -0x7FFFFFFF - 1 : 0x7FFFFFFF;
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}
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