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71 lines
2.6 KiB
C
71 lines
2.6 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 <stdint.h>
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#include "platform.h"
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#ifndef softfloat_countLeadingZeros64
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#define softfloat_countLeadingZeros64 softfloat_countLeadingZeros64
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#include "primitives.h"
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uint_fast8_t softfloat_countLeadingZeros64( uint64_t a )
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{
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uint_fast8_t count;
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uint32_t a32;
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count = 0;
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a32 = a>>32;
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if ( ! a32 ) {
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count = 32;
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a32 = a;
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}
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/*------------------------------------------------------------------------
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| From here, result is current count + count leading zeros of `a32'.
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*------------------------------------------------------------------------*/
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if ( a32 < 0x10000 ) {
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count += 16;
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a32 <<= 16;
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}
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if ( a32 < 0x1000000 ) {
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count += 8;
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a32 <<= 8;
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}
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count += softfloat_countLeadingZeros8[a32>>24];
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return count;
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}
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#endif
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