diff options
Diffstat (limited to 'arch/x86/include/asm/word-at-a-time.h')
| -rw-r--r-- | arch/x86/include/asm/word-at-a-time.h | 32 |
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 @@ * 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 @@ -37,10 +42,31 @@ static inline long count_masked_bytes(long mask) #endif -/* Return the high bit set in the first byte that is a zero */ -static inline unsigned long has_zero(unsigned long a) +/* 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) + +static inline unsigned long find_zero(unsigned long mask) { - return ((a - REPEAT_BYTE(0x01)) & ~a) & REPEAT_BYTE(0x80); + return count_masked_bytes(mask); } /* |