| Daniel Dunbar | fd08999 | 2009-06-26 16:47:03 +0000 | [diff] [blame^] | 1 | //===-- clzti2.c - Implement __clzti2 -------------------------------------===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // This file implements __clzti2 for the compiler_rt library. |
| 11 | // |
| 12 | //===----------------------------------------------------------------------===// |
| 13 | |
| 14 | #if __x86_64 |
| 15 | |
| 16 | #include "int_lib.h" |
| 17 | |
| 18 | // Returns: the number of leading 0-bits |
| 19 | |
| 20 | // Precondition: a != 0 |
| 21 | |
| 22 | si_int |
| 23 | __clzti2(ti_int a) |
| 24 | { |
| 25 | twords x; |
| 26 | x.all = a; |
| 27 | const di_int f = -(x.high == 0); |
| 28 | return __builtin_clzll((x.high & ~f) | (x.low & f)) + |
| 29 | ((si_int)f & ((si_int)(sizeof(di_int) * CHAR_BIT))); |
| 30 | } |
| 31 | |
| 32 | #endif |