1629372caa
This is much the same as for SPARC except that we can do the find_zero() function more efficiently using the count-leading-zeroes instructions. Tested on 32-bit and 64-bit PowerPC. Signed-off-by: Paul Mackerras <paulus@samba.org> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
41 lines
997 B
C
41 lines
997 B
C
#ifndef _ASM_WORD_AT_A_TIME_H
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#define _ASM_WORD_AT_A_TIME_H
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/*
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* Word-at-a-time interfaces for PowerPC.
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*/
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#include <linux/kernel.h>
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#include <asm/asm-compat.h>
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struct word_at_a_time {
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const unsigned long high_bits, low_bits;
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};
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#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) }
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/* Bit set in the bytes that have a zero */
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static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c)
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{
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unsigned long mask = (val & c->low_bits) + c->low_bits;
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return ~(mask | rhs);
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}
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#define create_zero_mask(mask) (mask)
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static inline long find_zero(unsigned long mask)
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{
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long leading_zero_bits;
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asm (PPC_CNTLZL "%0,%1" : "=r" (leading_zero_bits) : "r" (mask));
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return leading_zero_bits >> 3;
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}
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static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
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{
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unsigned long rhs = val | c->low_bits;
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*data = rhs;
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return (val + c->high_bits) & ~rhs;
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}
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#endif /* _ASM_WORD_AT_A_TIME_H */
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