diff options
| -rw-r--r-- | include/asm-arm/byteorder.h | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/include/asm-arm/byteorder.h b/include/asm-arm/byteorder.h index 741f5bc5d01..17eaf8bdf09 100644 --- a/include/asm-arm/byteorder.h +++ b/include/asm-arm/byteorder.h @@ -22,7 +22,16 @@ static inline __attribute_const__ __u32 ___arch__swab32(__u32 x) { __u32 t; - t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */ + if (__builtin_constant_p(x)) { + t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */ + } else { + /* + * The compiler needs a bit of a hint here to always do the + * right thing and not screw it up to different degrees + * depending on the gcc version. + */ + asm ("eor\t%0, %1, %1, ror #16" : "=r" (t) : "r" (x)); + } 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 */ |