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

40 lines
1.3 KiB
C

//===-- fixunsdfsi.c - Implement __fixunsdfsi -----------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements __fixunsdfsi for the compiler_rt library.
//
//===----------------------------------------------------------------------===//
#include "int_lib.h"
// Returns: convert a to a unsigned int, rounding toward zero.
// Negative values all become 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 su_int or is negative
// (no range checking performed)
// seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
su_int
__fixunsdfsi(double a)
{
double_bits fb;
fb.f = a;
int e = ((fb.u.high & 0x7FF00000) >> 20) - 1023;
if (e < 0 || (fb.u.high & 0x80000000))
return 0;
return (
0x80000000u |
((fb.u.high & 0x000FFFFF) << 11) |
(fb.u.low >> 21)
) >> (31 - e);
}