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Diffstat (limited to 'arch/x86/include/asm/word-at-a-time.h')
-rw-r--r--arch/x86/include/asm/word-at-a-time.h34
1 files changed, 30 insertions, 4 deletions
diff --git a/arch/x86/include/asm/word-at-a-time.h b/arch/x86/include/asm/word-at-a-time.h
index e58f03b206c3..5b238981542a 100644
--- a/arch/x86/include/asm/word-at-a-time.h
+++ b/arch/x86/include/asm/word-at-a-time.h
@@ -1,6 +1,8 @@
#ifndef _ASM_WORD_AT_A_TIME_H
#define _ASM_WORD_AT_A_TIME_H
+#include <linux/kernel.h>
+
/*
* This is largely generic for little-endian machines, but the
* optimal byte mask counting is probably going to be something
@@ -8,6 +10,11 @@
* bit count instruction, that might be better than the multiply
* and shift, for example.
*/
+struct word_at_a_time {
+ const unsigned long one_bits, high_bits;
+};
+
+#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
#ifdef CONFIG_64BIT
@@ -35,12 +42,31 @@ static inline long count_masked_bytes(long mask)
#endif
-#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x))
+/* Return nonzero if it has a zero */
+static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
+{
+ unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
+ *bits = mask;
+ return mask;
+}
+
+static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
+{
+ return bits;
+}
+
+static inline unsigned long create_zero_mask(unsigned long bits)
+{
+ bits = (bits - 1) & ~bits;
+ return bits >> 7;
+}
+
+/* The mask we created is directly usable as a bytemask */
+#define zero_bytemask(mask) (mask)
-/* Return the high bit set in the first byte that is a zero */
-static inline unsigned long has_zero(unsigned long a)
+static inline unsigned long find_zero(unsigned long mask)
{
- return ((a - REPEAT_BYTE(0x01)) & ~a) & REPEAT_BYTE(0x80);
+ return count_masked_bytes(mask);
}
/*