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

48 lines
1.2 KiB
C

/* ===-- fixunssfti.c - Implement __fixunssfti -----------------------------===
*
* 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 __fixunssfti for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
#include "int_lib.h"
#if __x86_64
/* Returns: convert a to a unsigned long long, rounding toward zero.
* Negative values all become zero.
*/
/* Assumption: float is a IEEE 32 bit floating point type
* tu_int is a 64 bit integral type
* value in float is representable in tu_int or is negative
* (no range checking performed)
*/
/* seee eeee emmm mmmm mmmm mmmm mmmm mmmm */
tu_int
__fixunssfti(float a)
{
float_bits fb;
fb.f = a;
int e = ((fb.u & 0x7F800000) >> 23) - 127;
if (e < 0 || (fb.u & 0x80000000))
return 0;
tu_int r = (fb.u & 0x007FFFFF) | 0x00800000;
if (e > 23)
r <<= (e - 23);
else
r >>= (23 - e);
return r;
}
#endif