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1da177e4 LT |
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 | */ | |
bb8cc641 | 13 | static inline unsigned long cris_swapnwbrlz(unsigned long w) |
1da177e4 LT |
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 | ||
bb8cc641 | 29 | static inline unsigned long cris_swapwbrlz(unsigned long w) |
1da177e4 LT |
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 | */ | |
bb8cc641 | 43 | static inline unsigned long ffz(unsigned long w) |
1da177e4 LT |
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 | */ | |
bb8cc641 | 54 | static inline unsigned long __ffs(unsigned long word) |
1da177e4 LT |
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 | ||
bb8cc641 | 68 | static inline unsigned long kernel_ffs(unsigned long w) |
1da177e4 LT |
69 | { |
70 | return w ? cris_swapwbrlz (w) + 1 : 0; | |
71 | } | |
72 | ||
73 | #endif |