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

40 lines
1.1 KiB
C

//===-- fixsfdi.c - Implement __fixsfdi -----------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements __fixsfdi for the compiler_rt library.
//
//===----------------------------------------------------------------------===//
#include "int_lib.h"
// 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 di_int (no range checking performed)
// seee eeee emmm mmmm mmmm mmmm mmmm mmmm
di_int
__fixsfdi(float a)
{
float_bits fb;
fb.f = a;
int e = ((fb.u & 0x7F800000) >> 23) - 127;
if (e < 0)
return 0;
di_int s = (si_int)(fb.u & 0x80000000) >> 31;
di_int r = (fb.u & 0x007FFFFF) | 0x00800000;
if (e > 23)
r <<= (e - 23);
else
r >>= (23 - e);
return (r ^ s) - s;
}