bitops.h

来自「omap3 linux 2.6 用nocc去除了冗余代码」· C头文件 代码 · 共 30 行

	.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]
	cmp	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	r2, r2, r3			@ toggle bit
	strexb	ip, r2, [r1]
	cmp	ip, #0
	bne	1b
	cmp	r0, #0
	movne	r0, #1
2:	mov	pc, lr
	.endm