diff options
Diffstat (limited to 'lib/builtins/clzdi2.c')
-rw-r--r-- | lib/builtins/clzdi2.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/lib/builtins/clzdi2.c b/lib/builtins/clzdi2.c new file mode 100644 index 000000000000..b9e64da492bd --- /dev/null +++ b/lib/builtins/clzdi2.c @@ -0,0 +1,29 @@ +/* ===-- clzdi2.c - Implement __clzdi2 -------------------------------------=== + * + * 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 __clzdi2 for the compiler_rt library. + * + * ===----------------------------------------------------------------------=== + */ + +#include "int_lib.h" + +/* Returns: the number of leading 0-bits */ + +/* Precondition: a != 0 */ + +COMPILER_RT_ABI si_int +__clzdi2(di_int a) +{ + dwords x; + x.all = a; + const si_int f = -(x.s.high == 0); + return __builtin_clz((x.s.high & ~f) | (x.s.low & f)) + + (f & ((si_int)(sizeof(si_int) * CHAR_BIT))); +} |