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

46 lines
1.2 KiB
C

/* ===-- fixsfti.c - Implement __fixsfti -----------------------------------===
*
* 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 __fixsfti for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
#include "int_lib.h"
#if __x86_64
/* Returns: convert a to a signed long long, rounding toward zero. */
/* Assumption: float is a IEEE 32 bit floating point type
* su_int is a 32 bit integral type
* value in float is representable in ti_int (no range checking performed)
*/
/* seee eeee emmm mmmm mmmm mmmm mmmm mmmm */
ti_int
__fixsfti(float a)
{
float_bits fb;
fb.f = a;
int e = ((fb.u & 0x7F800000) >> 23) - 127;
if (e < 0)
return 0;
ti_int s = (si_int)(fb.u & 0x80000000) >> 31;
ti_int r = (fb.u & 0x007FFFFF) | 0x00800000;
if (e > 23)
r <<= (e - 23);
else
r >>= (23 - e);
return (r ^ s) - s;
}
#endif