5bf6c07a18
This change enables the generic strncpy_from_user() and strnlen_user() using word-at-a-time.h. The tile implementation is trivial since both tilepro and tilegx have SIMD operations that do byte-wise comparisons against immediate zero for each byte, and return an 0x01 byte in each position where there is a 0x00 byte. Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
36 lines
897 B
C
36 lines
897 B
C
#ifndef _ASM_WORD_AT_A_TIME_H
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#define _ASM_WORD_AT_A_TIME_H
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#include <asm/byteorder.h>
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struct word_at_a_time { /* unused */ };
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#define WORD_AT_A_TIME_CONSTANTS {}
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/* Generate 0x01 byte values for non-zero bytes using a SIMD instruction. */
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static inline unsigned long has_zero(unsigned long val, unsigned long *data,
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const struct word_at_a_time *c)
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{
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#ifdef __tilegx__
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unsigned long mask = __insn_v1cmpeqi(val, 0);
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#else /* tilepro */
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unsigned long mask = __insn_seqib(val, 0);
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#endif
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*data = mask;
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return mask;
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}
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/* These operations are both nops. */
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#define prep_zero_mask(val, data, c) (data)
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#define create_zero_mask(data) (data)
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/* And this operation just depends on endianness. */
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static inline long find_zero(unsigned long mask)
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{
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#ifdef __BIG_ENDIAN
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return __builtin_clzl(mask) >> 3;
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#else
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return __builtin_ctzl(mask) >> 3;
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#endif
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}
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#endif /* _ASM_WORD_AT_A_TIME_H */
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