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-rw-r--r--arch/x86/include/asm/word-at-a-time.h32
1 files changed, 29 insertions, 3 deletions
diff --git a/arch/x86/include/asm/word-at-a-time.h b/arch/x86/include/asm/word-at-a-time.h
index ae03facfadd6..5b238981542a 100644
--- a/arch/x86/include/asm/word-at-a-time.h
+++ b/arch/x86/include/asm/word-at-a-time.h
@@ -10,6 +10,11 @@
10 * bit count instruction, that might be better than the multiply 10 * bit count instruction, that might be better than the multiply
11 * and shift, for example. 11 * and shift, for example.
12 */ 12 */
13struct word_at_a_time {
14 const unsigned long one_bits, high_bits;
15};
16
17#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
13 18
14#ifdef CONFIG_64BIT 19#ifdef CONFIG_64BIT
15 20
@@ -37,10 +42,31 @@ static inline long count_masked_bytes(long mask)
37 42
38#endif 43#endif
39 44
40/* Return the high bit set in the first byte that is a zero */ 45/* Return nonzero if it has a zero */
41static inline unsigned long has_zero(unsigned long a) 46static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
47{
48 unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
49 *bits = mask;
50 return mask;
51}
52
53static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
54{
55 return bits;
56}
57
58static inline unsigned long create_zero_mask(unsigned long bits)
59{
60 bits = (bits - 1) & ~bits;
61 return bits >> 7;
62}
63
64/* The mask we created is directly usable as a bytemask */
65#define zero_bytemask(mask) (mask)
66
67static inline unsigned long find_zero(unsigned long mask)
42{ 68{
43 return ((a - REPEAT_BYTE(0x01)) & ~a) & REPEAT_BYTE(0x80); 69 return count_masked_bytes(mask);
44} 70}
45 71
46/* 72/*