From: Russell King <rmk@dyn-67.arm.linux.org.uk>
Date: Sat, 16 Jul 2005 14:21:51 +0000 (+0100)
Subject: [PATCH] ARM: Convert bitops to use ARMv6 ldrex/strex instructions
X-Git-Tag: v2.6.13-rc4~88^2~3
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=54ea06f6afe85aaf419e51343d4e4b5599197113;p=linux-2.6

[PATCH] ARM: Convert bitops to use ARMv6 ldrex/strex instructions

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---

diff --git a/arch/arm/lib/bitops.h b/arch/arm/lib/bitops.h
index 4a83ab6cd5..6976e60e47 100644
--- a/arch/arm/lib/bitops.h
+++ b/arch/arm/lib/bitops.h
@@ -1,3 +1,33 @@
+#if __LINUX_ARM_ARCH__ >= 6
+	.macro	bitop, instr
+	mov	r2, #1
+	and	r3, r0, #7		@ Get bit offset
+	add	r1, r1, r0, lsr #3	@ Get byte offset
+	mov	r3, r2, lsl r3
+1:	ldrexb	r2, [r1]
+	\instr	r2, r2, r3
+	strexb	r0, r2, [r1]
+	cmpne	r0, #0
+	bne	1b
+	mov	pc, lr
+	.endm
+
+	.macro	testop, instr, store
+	and	r3, r0, #7		@ Get bit offset
+	mov	r2, #1
+	add	r1, r1, r0, lsr #3	@ Get byte offset
+	mov	r3, r2, lsl r3		@ create mask
+1:	ldrexb	r2, [r1]
+	ands	r0, r2, r3		@ save old value of bit
+	\instr	ip, r2, r3			@ toggle bit
+	strexb	r2, ip, [r1]
+	cmp	r2, #0
+	bne	1b
+	cmp	r0, #0
+	movne	r0, #1
+2:	mov	pc, lr
+	.endm
+#else
 	.macro	bitop, instr
 	and	r2, r0, #7
 	mov	r3, #1
@@ -31,3 +61,4 @@
 	moveq	r0, #0
 	mov	pc, lr
 	.endm
+#endif