1 #ifndef _ASM_WORD_AT_A_TIME_H
2 #define _ASM_WORD_AT_A_TIME_H
3 
4 /*
5  * Word-at-a-time interfaces for PowerPC.
6  */
7 
8 #include <linux/kernel.h>
9 #include <asm/asm-compat.h>
10 
11 #ifdef __BIG_ENDIAN__
12 
13 struct word_at_a_time {
14 	const unsigned long high_bits, low_bits;
15 };
16 
17 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) }
18 
19 /* Bit set in the bytes that have a zero */
20 static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c)
21 {
22 	unsigned long mask = (val & c->low_bits) + c->low_bits;
23 	return ~(mask | rhs);
24 }
25 
26 #define create_zero_mask(mask) (mask)
27 
28 static inline long find_zero(unsigned long mask)
29 {
30 	long leading_zero_bits;
31 
32 	asm (PPC_CNTLZL "%0,%1" : "=r" (leading_zero_bits) : "r" (mask));
33 	return leading_zero_bits >> 3;
34 }
35 
36 static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
37 {
38 	unsigned long rhs = val | c->low_bits;
39 	*data = rhs;
40 	return (val + c->high_bits) & ~rhs;
41 }
42 
43 #else
44 
45 struct word_at_a_time {
46 	const unsigned long one_bits, high_bits;
47 };
48 
49 #define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
50 
51 #ifdef CONFIG_64BIT
52 
53 /* Alan Modra's little-endian strlen tail for 64-bit */
54 #define create_zero_mask(mask) (mask)
55 
56 static inline unsigned long find_zero(unsigned long mask)
57 {
58 	unsigned long leading_zero_bits;
59 	long trailing_zero_bit_mask;
60 
61 	asm ("addi %1,%2,-1\n\t"
62 	     "andc %1,%1,%2\n\t"
63 	     "popcntd %0,%1"
64 	     : "=r" (leading_zero_bits), "=&r" (trailing_zero_bit_mask)
65 	     : "r" (mask));
66 	return leading_zero_bits >> 3;
67 }
68 
69 #else	/* 32-bit case */
70 
71 /*
72  * This is largely generic for little-endian machines, but the
73  * optimal byte mask counting is probably going to be something
74  * that is architecture-specific. If you have a reliably fast
75  * bit count instruction, that might be better than the multiply
76  * and shift, for example.
77  */
78 
79 /* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
80 static inline long count_masked_bytes(long mask)
81 {
82 	/* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
83 	long a = (0x0ff0001+mask) >> 23;
84 	/* Fix the 1 for 00 case */
85 	return a & mask;
86 }
87 
88 static inline unsigned long create_zero_mask(unsigned long bits)
89 {
90 	bits = (bits - 1) & ~bits;
91 	return bits >> 7;
92 }
93 
94 static inline unsigned long find_zero(unsigned long mask)
95 {
96 	return count_masked_bytes(mask);
97 }
98 
99 #endif
100 
101 /* Return nonzero if it has a zero */
102 static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
103 {
104 	unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
105 	*bits = mask;
106 	return mask;
107 }
108 
109 static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
110 {
111 	return bits;
112 }
113 
114 /* The mask we created is directly usable as a bytemask */
115 #define zero_bytemask(mask) (mask)
116 
117 #endif
118 
119 #endif /* _ASM_WORD_AT_A_TIME_H */
120