xref: /linux/arch/alpha/include/asm/word-at-a-time.h (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
1 #ifndef _ASM_WORD_AT_A_TIME_H
2 #define _ASM_WORD_AT_A_TIME_H
3 
4 #include <asm/compiler.h>
5 
6 /*
7  * word-at-a-time interface for Alpha.
8  */
9 
10 /*
11  * We do not use the word_at_a_time struct on Alpha, but it needs to be
12  * implemented to humour the generic code.
13  */
14 struct word_at_a_time {
15 	const unsigned long unused;
16 };
17 
18 #define WORD_AT_A_TIME_CONSTANTS { 0 }
19 
20 /* Return nonzero if val has a zero */
21 static inline unsigned long has_zero(unsigned long val, unsigned long *bits, const struct word_at_a_time *c)
22 {
23 	unsigned long zero_locations = __kernel_cmpbge(0, val);
24 	*bits = zero_locations;
25 	return zero_locations;
26 }
27 
28 static inline unsigned long prep_zero_mask(unsigned long val, unsigned long bits, const struct word_at_a_time *c)
29 {
30 	return bits;
31 }
32 
33 #define create_zero_mask(bits) (bits)
34 
35 static inline unsigned long find_zero(unsigned long bits)
36 {
37 #if defined(CONFIG_ALPHA_EV6) && defined(CONFIG_ALPHA_EV67)
38 	/* Simple if have CIX instructions */
39 	return __kernel_cttz(bits);
40 #else
41 	unsigned long t1, t2, t3;
42 	/* Retain lowest set bit only */
43 	bits &= -bits;
44 	/* Binary search for lowest set bit */
45 	t1 = bits & 0xf0;
46 	t2 = bits & 0xcc;
47 	t3 = bits & 0xaa;
48 	if (t1) t1 = 4;
49 	if (t2) t2 = 2;
50 	if (t3) t3 = 1;
51 	return t1 + t2 + t3;
52 #endif
53 }
54 
55 #endif /* _ASM_WORD_AT_A_TIME_H */
56