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Optimized byte-swapping macros for ARMv6.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@17148 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Michael Sevakis 2008-04-16 20:44:10 +00:00
parent a01996436d
commit bbb0c3f397
1 changed files with 21 additions and 0 deletions
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21
firmware/target/arm/system-arm.h
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@ -33,7 +33,14 @@ static inline uint16_t swap16(uint16_t value)
result[ 7..0] = value[15..8];
*/
{
#if ARM_ARCH >= 6
uint32_t retval;
asm volatile ("revsh %0, %1" /* xxAB */
: "=r"(retval) : "r"((uint32_t)value)); /* xxBA */
return retval;
#else
return (value >> 8) | (value << 8);
#endif
}
static inline uint32_t swap32(uint32_t value)
@ -44,6 +51,12 @@ static inline uint32_t swap32(uint32_t value)
result[ 7.. 0] = value[31..24];
*/
{
#if ARM_ARCH >= 6
uint32_t retval;
asm volatile ("rev %0, %1" /* ABCD */
: "=r"(retval) : "r"(value)); /* DCBA */
return retval;
#else
uint32_t tmp;
asm volatile (
@ -54,6 +67,7 @@ static inline uint32_t swap32(uint32_t value)
: "+r" (value), "=r" (tmp)
);
return value;
#endif
}
static inline uint32_t swap_odd_even32(uint32_t value)
@ -62,6 +76,12 @@ static inline uint32_t swap_odd_even32(uint32_t value)
result[31..24],[15.. 8] = value[23..16],[ 7.. 0]
result[23..16],[ 7.. 0] = value[31..24],[15.. 8]
*/
#if ARM_ARCH >= 6
uint32_t retval;
asm volatile ("rev16 %0, %1" /* ABCD */
: "=r"(retval) : "r"(value)); /* BADC */
return retval;
#else
uint32_t tmp;
asm volatile ( /* ABCD */
@ -72,6 +92,7 @@ static inline uint32_t swap_odd_even32(uint32_t value)
: "+r" (value), "=r" (tmp) /* BADC */
);
return value;
#endif
}
/* Core-level interrupt masking */