minix/sys/external/bsd/compiler_rt/dist/lib/fixdfti.c

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/* ===-- fixdfti.c - Implement __fixdfti -----------------------------------===
*
* The LLVM Compiler Infrastructure
*
* This file is dual licensed under the MIT and the University of Illinois Open
* Source Licenses. See LICENSE.TXT for details.
*
* ===----------------------------------------------------------------------===
*
* This file implements __fixdfti for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
#include "int_lib.h"
#if __x86_64
/* Returns: convert a to a signed long long, rounding toward zero. */
/* Assumption: double is a IEEE 64 bit floating point type
* su_int is a 32 bit integral type
* value in double is representable in ti_int (no range checking performed)
*/
/* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */
ti_int
__fixdfti(double a)
{
double_bits fb;
fb.f = a;
int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023;
if (e < 0)
return 0;
ti_int s = (si_int)(fb.u.s.high & 0x80000000) >> 31;
ti_int r = 0x0010000000000000uLL | (0x000FFFFFFFFFFFFFuLL & fb.u.all);
if (e > 52)
r <<= (e - 52);
else
r >>= (52 - e);
return (r ^ s) - s;
}
#endif