llvm-project/compiler-rt/lib/fixunsdfsi.c

43 lines
1.3 KiB
C

/* ===-- fixunsdfsi.c - Implement __fixunsdfsi -----------------------------===
*
* 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 __fixunsdfsi for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
#include "int_lib.h"
/* Returns: convert a to a unsigned int, rounding toward zero.
* Negative values all become 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 su_int or is negative
* (no range checking performed)
*/
/* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */
su_int
__fixunsdfsi(double a)
{
double_bits fb;
fb.f = a;
int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023;
if (e < 0 || (fb.u.s.high & 0x80000000))
return 0;
return (
0x80000000u |
((fb.u.s.high & 0x000FFFFF) << 11) |
(fb.u.s.low >> 21)
) >> (31 - e);
}