Messages in this thread Patch in this message | | | From | Yu-Jen Chang <> | Subject | [PATCH 1/2] lib/string.c: Add a macro for memchr_inv() | Date | Sun, 10 Jul 2022 22:28:21 +0800 |
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We add a macro MEMCHR_MASK_GEN() so that both memchr_inv() and memchr() can use it to generate a 8 bytes mask.
Signed-off-by: Yu-Jen Chang <arthurchang09@gmail.com> Signed-off-by: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw> --- lib/string.c | 34 ++++++++++++++++++++++++---------- 1 file changed, 24 insertions(+), 10 deletions(-)
diff --git a/lib/string.c b/lib/string.c index 485777c9d..80469e6c3 100644 --- a/lib/string.c +++ b/lib/string.c @@ -879,6 +879,29 @@ char *strnstr(const char *s1, const char *s2, size_t len) EXPORT_SYMBOL(strnstr); #endif +#if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64 + +#define MEMCHR_MASK_GEN(mask) (mask *= 0x0101010101010101ULL) + +#elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) + +#define MEMCHR_MASK_GEN(mask) \ + do { \ + mask *= 0x01010101; \ + mask |= mask << 32; \ + } while (0) + +#else + +#define MEMCHR_MASK_GEN(mask) \ + do { \ + mask |= mask << 8; \ + mask |= mask << 16; \ + mask |= mask << 32; \ + } while (0) + +#endif + #ifndef __HAVE_ARCH_MEMCHR /** * memchr - Find a character in an area of memory. @@ -932,16 +955,7 @@ void *memchr_inv(const void *start, int c, size_t bytes) return check_bytes8(start, value, bytes); value64 = value; -#if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64 - value64 *= 0x0101010101010101ULL; -#elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) - value64 *= 0x01010101; - value64 |= value64 << 32; -#else - value64 |= value64 << 8; - value64 |= value64 << 16; - value64 |= value64 << 32; -#endif + MEMCHR_MASK_GEN(value64); prefix = (unsigned long)start % 8; if (prefix) { -- 2.25.1
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