1/* asm/arch/bitops.h for Linux/CRISv10 */ 2 3#ifndef _CRIS_ARCH_BITOPS_H 4#define _CRIS_ARCH_BITOPS_H 5 6/* 7 * Helper functions for the core of the ff[sz] functions, wrapping the 8 * syntactically awkward asms. The asms compute the number of leading 9 * zeroes of a bits-in-byte and byte-in-word and word-in-dword-swapped 10 * number. They differ in that the first function also inverts all bits 11 * in the input. 12 */ 13static inline unsigned long cris_swapnwbrlz(unsigned long w) 14{ 15 /* Let's just say we return the result in the same register as the 16 input. Saying we clobber the input but can return the result 17 in another register: 18 ! __asm__ ("swapnwbr %2\n\tlz %2,%0" 19 ! : "=r,r" (res), "=r,X" (dummy) : "1,0" (w)); 20 confuses gcc (sched.c, gcc from cris-dist-1.14). */ 21 22 unsigned long res; 23 __asm__ ("swapnwbr %0 \n\t" 24 "lz %0,%0" 25 : "=r" (res) : "0" (w)); 26 return res; 27} 28 29static inline unsigned long cris_swapwbrlz(unsigned long w) 30{ 31 unsigned res; 32 __asm__ ("swapwbr %0 \n\t" 33 "lz %0,%0" 34 : "=r" (res) 35 : "0" (w)); 36 return res; 37} 38 39/* 40 * ffz = Find First Zero in word. Undefined if no zero exists, 41 * so code should check against ~0UL first.. 42 */ 43static inline unsigned long ffz(unsigned long w) 44{ 45 return cris_swapnwbrlz(w); 46} 47 48/** 49 * __ffs - find first bit in word. 50 * @word: The word to search 51 * 52 * Undefined if no bit exists, so code should check against 0 first. 53 */ 54static inline unsigned long __ffs(unsigned long word) 55{ 56 return cris_swapnwbrlz(~word); 57} 58 59/** 60 * ffs - find first bit set 61 * @x: the word to search 62 * 63 * This is defined the same way as 64 * the libc and compiler builtin ffs routines, therefore 65 * differs in spirit from the above ffz (man ffs). 66 */ 67 68static inline unsigned long kernel_ffs(unsigned long w) 69{ 70 return w ? cris_swapwbrlz (w) + 1 : 0; 71} 72 73#endif 74