diff options
| author | Andre McCurdy <armcc2000@yahoo.com> | 2006-01-07 11:39:20 +0000 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2006-01-07 11:39:20 +0000 |
| commit | 6351610d6906aacbf9176cbdd045dd3876eec4c0 (patch) | |
| tree | af6219c7a958f91c4d62fd1622954ed91ed1a9e7 /include/asm-arm/byteorder.h | |
| parent | 2c041f4b9be5cecbd0a042ecd9122a9db6f50416 (diff) | |
| download | lwn-6351610d6906aacbf9176cbdd045dd3876eec4c0.tar.gz lwn-6351610d6906aacbf9176cbdd045dd3876eec4c0.zip | |
[ARM] 3239/1: Add ARM optimised swab32
Patch from Andre McCurdy
Replaces generic swab32 routine with a more ARM friendly version.
Reduces kernel text size by approx 1200 bytes when compiled with
3.4.4 and approx 2400 bytes with 4.0.2
Probably some performance benefit as well.
Signed-off-by: Andre McCurdy <armccurdy@yahoo.co.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'include/asm-arm/byteorder.h')
| -rw-r--r-- | include/asm-arm/byteorder.h | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/include/asm-arm/byteorder.h b/include/asm-arm/byteorder.h index d648a1915c33..af42f449b9a6 100644 --- a/include/asm-arm/byteorder.h +++ b/include/asm-arm/byteorder.h @@ -15,9 +15,22 @@ #ifndef __ASM_ARM_BYTEORDER_H #define __ASM_ARM_BYTEORDER_H - #include <asm/types.h> +static inline __attribute_const__ __u32 ___arch__swab32(__u32 x) +{ + __u32 t; + + t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */ + x = (x << 24) | (x >> 8); /* mov r0,r0,ror #8 */ + t &= ~0x00FF0000; /* bic r1,r1,#0x00FF0000 */ + x ^= (t >> 8); /* eor r0,r0,r1,lsr #8 */ + + return x; +} + +#define __arch__swab32(x) ___arch__swab32(x) + #if !defined(__STRICT_ANSI__) || defined(__KERNEL__) # define __BYTEORDER_HAS_U64__ # define __SWAB_64_THRU_32__ |