[ARM] 3239/1: Add ARM optimised swab32 (6351610d) · Commits · 戴 / test

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>

include/asm-arm/byteorder.h

+14 −1

Original line number	Diff line number	Diff line
		@@ -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__

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