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/*****************************************************************
*
* The Compcert verified compiler
*
* Xavier Leroy, INRIA Paris-Rocquencourt
*
* Copyright (c) 2013 Institut National de Recherche en Informatique et
* en Automatique.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the <organization> nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT
* HOLDER> BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
**********************************************************************/
/* Helper functions for 64-bit integer arithmetic. Reference C implementation */
#include "i64.h"
/* Conversion float64 -> unsigned int64 */
unsigned long long i64_dtou(double d)
{
/* Extract bits of d's representation */
union { double d; unsigned long long i; } buf;
buf.d = d;
unsigned int h = buf.i >> 32;
/* Negative FP numbers convert to 0 */
if ((int) h < 0) return 0ULL;
/* Extract unbiased exponent */
int e = ((h & 0x7FF00000) >> 20) - (1023 + 52);
/* Check range of exponent */
if (e < -52) {
/* d is less than 1.0 */
return 0ULL;
}
if (e >= 64 - 52) {
/* d is greater or equal to 2^64 */
return 0xFFFFFFFFFFFFFFFFULL; /* max unsigned long long */
}
/* Extract true mantissa */
unsigned long long m =
(buf.i & ~0xFFF0000000000000LL) | 0x0010000000000000LL;
/* Shift it appropriately */
if (e >= 0)
return i64_shl(m, e);
else
return i64_shr(m, -e);
}
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