1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * lib/clz_ctz.c 4 * 5 * Copyright (C) 2013 Chanho Min <chanho.min@lge.com> 6 * 7 * The functions in this file aren't called directly, but are required by 8 * GCC builtins such as __builtin_ctz, and therefore they can't be removed 9 * despite appearing unreferenced in kernel source. 10 * 11 * __c[lt]z[sd]i2 can be overridden by linking arch-specific versions. 12 */ 13 14 #include <linux/export.h> 15 #include <linux/kernel.h> 16 17 int __weak __ctzsi2(int val); 18 int __weak __ctzsi2(int val) 19 { 20 return __ffs(val); 21 } 22 EXPORT_SYMBOL(__ctzsi2); 23 24 int __weak __clzsi2(int val); 25 int __weak __clzsi2(int val) 26 { 27 return 32 - fls(val); 28 } 29 EXPORT_SYMBOL(__clzsi2); 30 31 int __weak __clzdi2(long val); 32 int __weak __ctzdi2(long val); 33 #if BITS_PER_LONG == 32 34 35 int __weak __clzdi2(long val) 36 { 37 return 32 - fls((int)val); 38 } 39 EXPORT_SYMBOL(__clzdi2); 40 41 int __weak __ctzdi2(long val) 42 { 43 return __ffs((u32)val); 44 } 45 EXPORT_SYMBOL(__ctzdi2); 46 47 #elif BITS_PER_LONG == 64 48 49 int __weak __clzdi2(long val) 50 { 51 return 64 - fls64((u64)val); 52 } 53 EXPORT_SYMBOL(__clzdi2); 54 55 int __weak __ctzdi2(long val) 56 { 57 return __ffs64((u64)val); 58 } 59 EXPORT_SYMBOL(__ctzdi2); 60 61 #else 62 #error BITS_PER_LONG not 32 or 64 63 #endif 64