diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig | 1 | ||||
| -rw-r--r-- | lib/crc32.c | 28 |
2 files changed, 6 insertions, 23 deletions
diff --git a/lib/Kconfig b/lib/Kconfig index 0d683559080..47b172df3e3 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -26,6 +26,7 @@ config CRC16 config CRC32 tristate "CRC32 functions" default y + select BITREVERSE help This option is provided for the case where no in-kernel-tree modules require CRC32 functions, but a module built outside the diff --git a/lib/crc32.c b/lib/crc32.c index 285fd9bc61b..bfc33314c72 100644 --- a/lib/crc32.c +++ b/lib/crc32.c @@ -235,23 +235,8 @@ u32 __attribute_pure__ crc32_be(u32 crc, unsigned char const *p, size_t len) } #endif -/** - * bitreverse - reverse the order of bits in a u32 value - * @x: value to be bit-reversed - */ -u32 bitreverse(u32 x) -{ - x = (x >> 16) | (x << 16); - x = (x >> 8 & 0x00ff00ff) | (x << 8 & 0xff00ff00); - x = (x >> 4 & 0x0f0f0f0f) | (x << 4 & 0xf0f0f0f0); - x = (x >> 2 & 0x33333333) | (x << 2 & 0xcccccccc); - x = (x >> 1 & 0x55555555) | (x << 1 & 0xaaaaaaaa); - return x; -} - EXPORT_SYMBOL(crc32_le); EXPORT_SYMBOL(crc32_be); -EXPORT_SYMBOL(bitreverse); /* * A brief CRC tutorial. @@ -400,10 +385,7 @@ buf_dump(char const *prefix, unsigned char const *buf, size_t len) static void bytereverse(unsigned char *buf, size_t len) { while (len--) { - unsigned char x = *buf; - x = (x >> 4) | (x << 4); - x = (x >> 2 & 0x33) | (x << 2 & 0xcc); - x = (x >> 1 & 0x55) | (x << 1 & 0xaa); + unsigned char x = bitrev8(*buf); *buf++ = x; } } @@ -460,11 +442,11 @@ static u32 test_step(u32 init, unsigned char *buf, size_t len) /* Now swap it around for the other test */ bytereverse(buf, len + 4); - init = bitreverse(init); - crc2 = bitreverse(crc1); - if (crc1 != bitreverse(crc2)) + init = bitrev32(init); + crc2 = bitrev32(crc1); + if (crc1 != bitrev32(crc2)) printf("\nBit reversal fail: 0x%08x -> 0x%08x -> 0x%08x\n", - crc1, crc2, bitreverse(crc2)); + crc1, crc2, bitrev32(crc2)); crc1 = crc32_le(init, buf, len); if (crc1 != crc2) printf("\nCRC endianness fail: 0x%08x != 0x%08x\n", crc1, |