aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/lib/bitops.h
blob: 10d868a5a48135840278022e153f3610b0b7a640 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
#if __LINUX_ARM_ARCH__ >= 6
	.macro	bitop, instr
	ands	ip, r1, #3
	strneb	r1, [ip]		@ assert word-aligned
	mov	r2, #1
	and	r3, r0, #31		@ Get bit offset
	mov	r0, r0, lsr #5
	add	r1, r1, r0, lsl #2	@ Get word offset
	mov	r3, r2, lsl r3
1:	ldrex	r2, [r1]
	\instr	r2, r2, r3
	strex	r0, r2, [r1]
	cmp	r0, #0
	bne	1b
	bx	lr
	.endm

	.macro	testop, instr, store
	ands	ip, r1, #3
	strneb	r1, [ip]		@ assert word-aligned
	mov	r2, #1
	and	r3, r0, #31		@ Get bit offset
	mov	r0, r0, lsr #5
	add	r1, r1, r0, lsl #2	@ Get word offset
	mov	r3, r2, lsl r3		@ create mask
	smp_dmb
1:	ldrex	r2, [r1]
	ands	r0, r2, r3		@ save old value of bit
	\instr	r2, r2, r3		@ toggle bit
	strex	ip, r2, [r1]
	cmp	ip, #0
	bne	1b
	smp_dmb
	cmp	r0, #0
	movne	r0, #1
2:	bx	lr
	.endm
#else
	.macro	bitop, instr
	ands	ip, r1, #3
	strneb	r1, [ip]		@ assert word-aligned
	and	r2, r0, #31
	mov	r0, r0, lsr #5
	mov	r3, #1
	mov	r3, r3, lsl r2
	save_and_disable_irqs ip
	ldr	r2, [r1, r0, lsl #2]
	\instr	r2, r2, r3
	str	r2, [r1, r0, lsl #2]
	restore_irqs ip
	mov	pc, lr
	.endm

/**
 * testop - implement a test_and_xxx_bit operation.
 * @instr: operational instruction
 * @store: store instruction
 *
 * Note: we can trivially conditionalise the store instruction
 * to avoid dirtying the data cache.
 */
	.macro	testop, instr, store
	ands	ip, r1, #3
	strneb	r1, [ip]		@ assert word-aligned
	and	r3, r0, #31
	mov	r0, r0, lsr #5
	save_and_disable_irqs ip
	ldr	r2, [r1, r0, lsl #2]!
	mov	r0, #1
	tst	r2, r0, lsl r3
	\instr	r2, r2, r0, lsl r3
	\store	r2, [r1]
	moveq	r0, #0
	restore_irqs ip
	mov	pc, lr
	.endm
#endif