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

46 lines
1.3 KiB
C

/* ===-- fixunsdfdi.c - Implement __fixunsdfdi -----------------------------===
*
* The LLVM Compiler Infrastructure
*
* This file is distributed under the University of Illinois Open Source
* License. See LICENSE.TXT for details.
*
* ===----------------------------------------------------------------------===
*
* This file implements __fixunsdfdi for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
#include "int_lib.h"
/* Returns: convert a to a unsigned long long, rounding toward zero.
* Negative values all become zero.
*/
/* Assumption: double is a IEEE 64 bit floating point type
* du_int is a 64 bit integral type
* value in double is representable in du_int or is negative
* (no range checking performed)
*/
/* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */
du_int
__fixunsdfdi(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;
udwords 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;
}