static u8 *check_bytes(u8 *start, u8 value, unsigned int bytes) { u64 value64; unsigned int words, prefix; if (bytes <= 16) return check_bytes8(start, value, bytes); value64 = value | value << 8 | value << 16 | value << 24; value64 = (value64 & 0xffffffff) | value64 << 32; prefix = 8 - ((unsigned long)start) % 8; if (prefix) { u8 *r = check_bytes8(start, value, prefix); if (r) return r; start += prefix; bytes -= prefix; } words = bytes / 8; while (words) { if (*(u64 *)start != value64) return check_bytes8(start, value, 8); start += 8; words--; } return check_bytes8(start, value, bytes % 8); }
/** * memchr_inv - Find an unmatching character in an area of memory. * @start: The memory area * @c: Find a character other than c * @bytes: The size of the area. * * returns the address of the first character other than @c, or %NULL * if the whole buffer contains just @c. */ void *memchr_inv(const void *start, int c, size_t bytes) { u8 value = c; u64 value64; unsigned int words, prefix; if (bytes <= 16) return check_bytes8(start, value, bytes); value64 = value | value << 8 | value << 16 | value << 24; value64 = (value64 & 0xffffffff) | value64 << 32; prefix = 8 - ((unsigned long)start) % 8; if (prefix) { u8 *r = check_bytes8(start, value, prefix); if (r) return r; start += prefix; bytes -= prefix; } words = bytes / 8; while (words) { if (*(u64 *)start != value64) return check_bytes8(start, value, 8); start += 8; words--; } return check_bytes8(start, value, bytes % 8); }
/** * memchr_inv - Find an unmatching character in an area of memory. * @start: The memory area * @c: Find a character other than c * @bytes: The size of the area. * * returns the address of the first character other than @c, or %NULL * if the whole buffer contains just @c. */ void *memchr_inv(const void *start, int c, size_t bytes) { u8 value = c; u64 value64; unsigned int words, prefix; if (bytes <= 16) return check_bytes8(start, value, bytes); value64 = value; #if defined(ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64 value64 *= 0x0101010101010101; #elif defined(ARCH_HAS_FAST_MULTIPLIER) value64 *= 0x01010101; value64 |= value64 << 32; #else value64 |= value64 << 8; value64 |= value64 << 16; value64 |= value64 << 32; #endif prefix = (unsigned long)start % 8; if (prefix) { u8 *r; prefix = 8 - prefix; r = check_bytes8(start, value, prefix); if (r) return r; start += prefix; bytes -= prefix; } words = bytes / 8; while (words) { if (*(u64 *)start != value64) return check_bytes8(start, value, 8); start += 8; words--; } return check_bytes8(start, value, bytes % 8); }