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

46 lines
1.3 KiB
C

/* ===-- fixdfdi.c - Implement __fixdfdi -----------------------------------===
*
* 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 __fixdfdi for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
#include "int_lib.h"
/* 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 di_int (no range checking performed)
*/
/* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */
ARM_EABI_FNALIAS(d2lz, fixdfdi)
di_int
__fixdfdi(double a)
{
double_bits fb;
fb.f = a;
int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023;
if (e < 0)
return 0;
di_int s = (si_int)(fb.u.s.high & 0x80000000) >> 31;
dwords r;
r.s.high = (fb.u.s.high & 0x000FFFFF) | 0x00100000;
r.s.low = fb.u.s.low;
if (e > 52)
r.all <<= (e - 52);
else
r.all >>= (52 - e);
return (r.all ^ s) - s;
}