diff options
Diffstat (limited to 'lib/crc32.c')
| -rw-r--r-- | lib/crc32.c | 139 |
1 files changed, 52 insertions, 87 deletions
diff --git a/lib/crc32.c b/lib/crc32.c index 49d1c9e3ce38..0f45fbff34cb 100644 --- a/lib/crc32.c +++ b/lib/crc32.c @@ -30,11 +30,15 @@ #include <asm/atomic.h> #include "crc32defs.h" #if CRC_LE_BITS == 8 -#define tole(x) __constant_cpu_to_le32(x) -#define tobe(x) __constant_cpu_to_be32(x) +# define tole(x) __constant_cpu_to_le32(x) #else -#define tole(x) (x) -#define tobe(x) (x) +# define tole(x) (x) +#endif + +#if CRC_BE_BITS == 8 +# define tobe(x) __constant_cpu_to_be32(x) +#else +# define tobe(x) (x) #endif #include "crc32table.h" @@ -42,6 +46,48 @@ MODULE_AUTHOR("Matt Domsch <Matt_Domsch@dell.com>"); MODULE_DESCRIPTION("Ethernet CRC32 calculations"); MODULE_LICENSE("GPL"); +#if CRC_LE_BITS == 8 || CRC_BE_BITS == 8 + +static inline u32 +crc32_body(u32 crc, unsigned char const *buf, size_t len, const u32 *tab) +{ +# ifdef __LITTLE_ENDIAN +# define DO_CRC(x) crc = tab[(crc ^ (x)) & 255 ] ^ (crc >> 8) +# else +# define DO_CRC(x) crc = tab[((crc >> 24) ^ (x)) & 255] ^ (crc << 8) +# endif + const u32 *b; + size_t rem_len; + + /* Align it */ + if (unlikely((long)buf & 3 && len)) { + do { + DO_CRC(*buf++); + } while ((--len) && ((long)buf)&3); + } + rem_len = len & 3; + /* load data 32 bits wide, xor data 32 bits wide. */ + len = len >> 2; + b = (const u32 *)buf; + for (--b; len; --len) { + crc ^= *++b; /* use pre increment for speed */ + DO_CRC(0); + DO_CRC(0); + DO_CRC(0); + DO_CRC(0); + } + len = rem_len; + /* And the last few bytes */ + if (len) { + u8 *p = (u8 *)(b + 1) - 1; + do { + DO_CRC(*++p); /* use pre increment for speed */ + } while (--len); + } + return crc; +#undef DO_CRC +} +#endif /** * crc32_le() - Calculate bitwise little-endian Ethernet AUTODIN II CRC32 * @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for @@ -72,52 +118,11 @@ u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len) u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len) { # if CRC_LE_BITS == 8 - const u32 *b =(u32 *)p; const u32 *tab = crc32table_le; -# ifdef __LITTLE_ENDIAN -# define DO_CRC(x) crc = tab[ (crc ^ (x)) & 255 ] ^ (crc>>8) -# else -# define DO_CRC(x) crc = tab[ ((crc >> 24) ^ (x)) & 255] ^ (crc<<8) -# endif - crc = __cpu_to_le32(crc); - /* Align it */ - if(unlikely(((long)b)&3 && len)){ - do { - u8 *p = (u8 *)b; - DO_CRC(*p++); - b = (void *)p; - } while ((--len) && ((long)b)&3 ); - } - if(likely(len >= 4)){ - /* load data 32 bits wide, xor data 32 bits wide. */ - size_t save_len = len & 3; - len = len >> 2; - --b; /* use pre increment below(*++b) for speed */ - do { - crc ^= *++b; - DO_CRC(0); - DO_CRC(0); - DO_CRC(0); - DO_CRC(0); - } while (--len); - b++; /* point to next byte(s) */ - len = save_len; - } - /* And the last few bytes */ - if(len){ - do { - u8 *p = (u8 *)b; - DO_CRC(*p++); - b = (void *)p; - } while (--len); - } - + crc = crc32_body(crc, p, len, tab); return __le32_to_cpu(crc); -#undef ENDIAN_SHIFT -#undef DO_CRC - # elif CRC_LE_BITS == 4 while (len--) { crc ^= *p++; @@ -170,51 +175,11 @@ u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len) u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len) { # if CRC_BE_BITS == 8 - const u32 *b =(u32 *)p; const u32 *tab = crc32table_be; -# ifdef __LITTLE_ENDIAN -# define DO_CRC(x) crc = tab[ (crc ^ (x)) & 255 ] ^ (crc>>8) -# else -# define DO_CRC(x) crc = tab[ ((crc >> 24) ^ (x)) & 255] ^ (crc<<8) -# endif - crc = __cpu_to_be32(crc); - /* Align it */ - if(unlikely(((long)b)&3 && len)){ - do { - u8 *p = (u8 *)b; - DO_CRC(*p++); - b = (u32 *)p; - } while ((--len) && ((long)b)&3 ); - } - if(likely(len >= 4)){ - /* load data 32 bits wide, xor data 32 bits wide. */ - size_t save_len = len & 3; - len = len >> 2; - --b; /* use pre increment below(*++b) for speed */ - do { - crc ^= *++b; - DO_CRC(0); - DO_CRC(0); - DO_CRC(0); - DO_CRC(0); - } while (--len); - b++; /* point to next byte(s) */ - len = save_len; - } - /* And the last few bytes */ - if(len){ - do { - u8 *p = (u8 *)b; - DO_CRC(*p++); - b = (void *)p; - } while (--len); - } + crc = crc32_body(crc, p, len, tab); return __be32_to_cpu(crc); -#undef ENDIAN_SHIFT -#undef DO_CRC - # elif CRC_BE_BITS == 4 while (len--) { crc ^= *p++ << 24; |
