1 /* 2 * include/asm-xtensa/bitops.h 3 * 4 * Atomic operations that C can't guarantee us.Useful for resource counting etc. 5 * 6 * This file is subject to the terms and conditions of the GNU General Public 7 * License. See the file "COPYING" in the main directory of this archive 8 * for more details. 9 * 10 * Copyright (C) 2001 - 2007 Tensilica Inc. 11 */ 12 13 #ifndef _XTENSA_BITOPS_H 14 #define _XTENSA_BITOPS_H 15 16 #ifdef __KERNEL__ 17 18 #ifndef _LINUX_BITOPS_H 19 #error only <linux/bitops.h> can be included directly 20 #endif 21 22 #include <asm/processor.h> 23 #include <asm/byteorder.h> 24 25 #ifdef CONFIG_SMP 26 # error SMP not supported on this architecture 27 #endif 28 29 #define smp_mb__before_clear_bit() barrier() 30 #define smp_mb__after_clear_bit() barrier() 31 32 #include <asm-generic/bitops/atomic.h> 33 #include <asm-generic/bitops/non-atomic.h> 34 35 #if XCHAL_HAVE_NSA 36 37 static inline unsigned long __cntlz (unsigned long x) 38 { 39 int lz; 40 asm ("nsau %0, %1" : "=r" (lz) : "r" (x)); 41 return lz; 42 } 43 44 /* 45 * ffz: Find first zero in word. Undefined if no zero exists. 46 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). 47 */ 48 49 static inline int ffz(unsigned long x) 50 { 51 return 31 - __cntlz(~x & -~x); 52 } 53 54 /* 55 * __ffs: Find first bit set in word. Return 0 for bit 0 56 */ 57 58 static inline int __ffs(unsigned long x) 59 { 60 return 31 - __cntlz(x & -x); 61 } 62 63 /* 64 * ffs: Find first bit set in word. This is defined the same way as 65 * the libc and compiler builtin ffs routines, therefore 66 * differs in spirit from the above ffz (man ffs). 67 */ 68 69 static inline int ffs(unsigned long x) 70 { 71 return 32 - __cntlz(x & -x); 72 } 73 74 /* 75 * fls: Find last (most-significant) bit set in word. 76 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32. 77 */ 78 79 static inline int fls (unsigned int x) 80 { 81 return 32 - __cntlz(x); 82 } 83 84 /** 85 * __fls - find last (most-significant) set bit in a long word 86 * @word: the word to search 87 * 88 * Undefined if no set bit exists, so code should check against 0 first. 89 */ 90 static inline unsigned long __fls(unsigned long word) 91 { 92 return 31 - __cntlz(word); 93 } 94 #else 95 96 /* Use the generic implementation if we don't have the nsa/nsau instructions. */ 97 98 # include <asm-generic/bitops/ffs.h> 99 # include <asm-generic/bitops/__ffs.h> 100 # include <asm-generic/bitops/ffz.h> 101 # include <asm-generic/bitops/fls.h> 102 # include <asm-generic/bitops/__fls.h> 103 104 #endif 105 106 #include <asm-generic/bitops/fls64.h> 107 #include <asm-generic/bitops/find.h> 108 #include <asm-generic/bitops/le.h> 109 110 #include <asm-generic/bitops/ext2-atomic-setbit.h> 111 112 #include <asm-generic/bitops/hweight.h> 113 #include <asm-generic/bitops/lock.h> 114 #include <asm-generic/bitops/sched.h> 115 116 #endif /* __KERNEL__ */ 117 118 #endif /* _XTENSA_BITOPS_H */ 119