xref: /minix3/sys/external/bsd/compiler_rt/dist/lib/builtins/clzti2.c (revision 0a6a1f1d05b60e214de2f05a7310ddd1f0e590e7)
1*0a6a1f1dSLionel Sambuc /* ===-- clzti2.c - Implement __clzti2 -------------------------------------===
2*0a6a1f1dSLionel Sambuc  *
3*0a6a1f1dSLionel Sambuc  *      	       The LLVM Compiler Infrastructure
4*0a6a1f1dSLionel Sambuc  *
5*0a6a1f1dSLionel Sambuc  * This file is dual licensed under the MIT and the University of Illinois Open
6*0a6a1f1dSLionel Sambuc  * Source Licenses. See LICENSE.TXT for details.
7*0a6a1f1dSLionel Sambuc  *
8*0a6a1f1dSLionel Sambuc  * ===----------------------------------------------------------------------===
9*0a6a1f1dSLionel Sambuc  *
10*0a6a1f1dSLionel Sambuc  * This file implements __clzti2 for the compiler_rt library.
11*0a6a1f1dSLionel Sambuc  *
12*0a6a1f1dSLionel Sambuc  * ===----------------------------------------------------------------------===
13*0a6a1f1dSLionel Sambuc  */
14*0a6a1f1dSLionel Sambuc 
15*0a6a1f1dSLionel Sambuc #include "int_lib.h"
16*0a6a1f1dSLionel Sambuc 
17*0a6a1f1dSLionel Sambuc #ifdef CRT_HAS_128BIT
18*0a6a1f1dSLionel Sambuc 
19*0a6a1f1dSLionel Sambuc /* Returns: the number of leading 0-bits */
20*0a6a1f1dSLionel Sambuc 
21*0a6a1f1dSLionel Sambuc /* Precondition: a != 0 */
22*0a6a1f1dSLionel Sambuc 
23*0a6a1f1dSLionel Sambuc COMPILER_RT_ABI si_int
__clzti2(ti_int a)24*0a6a1f1dSLionel Sambuc __clzti2(ti_int a)
25*0a6a1f1dSLionel Sambuc {
26*0a6a1f1dSLionel Sambuc     twords x;
27*0a6a1f1dSLionel Sambuc     x.all = a;
28*0a6a1f1dSLionel Sambuc     const di_int f = -(x.s.high == 0);
29*0a6a1f1dSLionel Sambuc     return __builtin_clzll((x.s.high & ~f) | (x.s.low & f)) +
30*0a6a1f1dSLionel Sambuc            ((si_int)f & ((si_int)(sizeof(di_int) * CHAR_BIT)));
31*0a6a1f1dSLionel Sambuc }
32*0a6a1f1dSLionel Sambuc 
33*0a6a1f1dSLionel Sambuc #endif /* CRT_HAS_128BIT */
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