1 #ifndef _ASM_WORD_AT_A_TIME_H
2 #define _ASM_WORD_AT_A_TIME_H
3 
4 /*
5  * This says "generic", but it's actually big-endian only.
6  * Little-endian can use more efficient versions of these
7  * interfaces, see for example
8  *	 arch/x86/include/asm/word-at-a-time.h
9  * for those.
10  */
11 
12 #include <linux/kernel.h>
13 
14 struct word_at_a_time {
15 	const unsigned long high_bits, low_bits;
16 };
17 
18 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) }
19 
20 /* Bit set in the bytes that have a zero */
21 static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c)
22 {
23 	unsigned long mask = (val & c->low_bits) + c->low_bits;
24 	return ~(mask | rhs);
25 }
26 
27 #define create_zero_mask(mask) (mask)
28 
29 static inline long find_zero(unsigned long mask)
30 {
31 	long byte = 0;
32 #ifdef CONFIG_64BIT
33 	if (mask >> 32)
34 		mask >>= 32;
35 	else
36 		byte = 4;
37 #endif
38 	if (mask >> 16)
39 		mask >>= 16;
40 	else
41 		byte += 2;
42 	return (mask >> 8) ? byte : byte + 1;
43 }
44 
45 static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
46 {
47 	unsigned long rhs = val | c->low_bits;
48 	*data = rhs;
49 	return (val + c->high_bits) & ~rhs;
50 }
51 
52 #ifndef zero_bytemask
53 #define zero_bytemask(mask) (~1ul << __fls(mask))
54 #endif
55 
56 #endif /* _ASM_WORD_AT_A_TIME_H */
57