From ca9211ecdede9bdedb812b2243a4abdb8dacd1b9 Mon Sep 17 00:00:00 2001 From: Dimitry Andric Date: Wed, 7 Jan 2015 19:55:37 +0000 Subject: Import compiler-rt trunk r224034. https://llvm.org/svn/llvm-project/compiler-rt/trunk@224034 --- lib/builtins/ctzdi2.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 lib/builtins/ctzdi2.c (limited to 'lib/builtins/ctzdi2.c') diff --git a/lib/builtins/ctzdi2.c b/lib/builtins/ctzdi2.c new file mode 100644 index 000000000000..db3c6fdc08f1 --- /dev/null +++ b/lib/builtins/ctzdi2.c @@ -0,0 +1,29 @@ +/* ===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------=== + * + * 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 __ctzdi2 for the compiler_rt library. + * + * ===----------------------------------------------------------------------=== + */ + +#include "int_lib.h" + +/* Returns: the number of trailing 0-bits */ + +/* Precondition: a != 0 */ + +COMPILER_RT_ABI si_int +__ctzdi2(di_int a) +{ + dwords x; + x.all = a; + const si_int f = -(x.s.low == 0); + return __builtin_ctz((x.s.high & f) | (x.s.low & ~f)) + + (f & ((si_int)(sizeof(si_int) * CHAR_BIT))); +} -- cgit v1.2.3