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[ARM] Fix byte order macros for Thumb 

The byte order functions are visible to userspace.  Unfortunately,
__arch_swab32() contains an assembly instruction which is invalid when
compiling for Thumb.  This reverts to the C version when compiling for
Thumb.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
H. Peter Anvin 2006-06-19 15:35:36 +01:00 committed by Russell King
parent 5e64238717
commit 441ff855f3
1 changed files with 6 additions and 4 deletions
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10
include/asm-arm/byteorder.h
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@ -22,16 +22,18 @@ static inline __attribute_const__ __u32 ___arch__swab32(__u32 x)
{
__u32 t;
if (__builtin_constant_p(x)) {
t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */
} else {
#ifndef __thumb__
if (!__builtin_constant_p(x)) {
/*
* 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));
}
} else
#endif
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 */