llvm-project/compiler-rt/lib/builtins/fixxfdi.c

45 lines
1.3 KiB
C

/* ===-- fixxfdi.c - Implement __fixxfdi -----------------------------------===
*
* 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 __fixxfdi for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
#if !_ARCH_PPC
#include "int_lib.h"
/* Returns: convert a to a signed long long, rounding toward zero. */
/* Assumption: long double is an intel 80 bit floating point type padded with 6 bytes
* su_int is a 32 bit integral type
* value in long double is representable in di_int (no range checking performed)
*/
/* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
* 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
*/
COMPILER_RT_ABI di_int
__fixxfdi(long double a)
{
long_double_bits fb;
fb.f = a;
int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
if (e < 0)
return 0;
di_int s = -(si_int)((fb.u.high.s.low & 0x00008000) >> 15);
di_int r = fb.u.low.all;
r = (du_int)r >> (63 - e);
return (r ^ s) - s;
}
#endif /* !_ARCH_PPC */