llvm-project/compiler-rt/lib/ctzti2.c

33 lines
823 B
C

//===-- ctzti2.c - Implement __ctzti2 -------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements __ctzti2 for the compiler_rt library.
//
//===----------------------------------------------------------------------===//
#if __x86_64
#include "int_lib.h"
// Returns: the number of trailing 0-bits
// Precondition: a != 0
si_int
__ctzti2(ti_int a)
{
twords x;
x.all = a;
const di_int f = -(x.low == 0);
return __builtin_ctzll((x.high & f) | (x.low & ~f)) +
((si_int)f & ((si_int)(sizeof(di_int) * CHAR_BIT)));
}
#endif