linux/arch/arm/lib/bswapsdi2.S
Kim Phillips 017f161a55 ARM: 7877/1: use built-in byte swap function
Enable the compiler intrinsic for byte swapping on arch ARM. This
allows the compiler to detect and be able to optimize out byte
swappings, and has a very modest benefit on vmlinux size (Linaro gcc
4.8):

text data bss dec hex filename
2840310 123932 61960 3026202 2e2d1a vmlinux-lart #orig
2840152 123932 61960 3026044 2e2c7c vmlinux-lart #builtin-bswap

6473120 314840 5616016 12403976 bd4508 vmlinux-mxs #orig
6472586 314848 5616016 12403450 bd42fa vmlinux-mxs #builtin-bswap

7419872 318372 379556 8117800 7bde28 vmlinux-imx_v6_v7 #orig
7419170 318364 379556 8117090 7bdb62 vmlinux-imx_v6_v7 #builtin-bswap

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-12-29 12:32:45 +00:00

37 lines
591 B
ArmAsm

#include <linux/linkage.h>
#if __LINUX_ARM_ARCH__ >= 6
ENTRY(__bswapsi2)
rev r0, r0
bx lr
ENDPROC(__bswapsi2)
ENTRY(__bswapdi2)
rev r3, r0
rev r0, r1
mov r1, r3
bx lr
ENDPROC(__bswapdi2)
#else
ENTRY(__bswapsi2)
eor r3, r0, r0, ror #16
mov r3, r3, lsr #8
bic r3, r3, #0xff00
eor r0, r3, r0, ror #8
mov pc, lr
ENDPROC(__bswapsi2)
ENTRY(__bswapdi2)
mov ip, r1
eor r3, ip, ip, ror #16
eor r1, r0, r0, ror #16
mov r1, r1, lsr #8
mov r3, r3, lsr #8
bic r3, r3, #0xff00
bic r1, r1, #0xff00
eor r1, r1, r0, ror #8
eor r0, r3, ip, ror #8
mov pc, lr
ENDPROC(__bswapdi2)
#endif