1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * linux/arch/arm/lib/findbit.S
4 *
5 * Copyright (C) 1995-2000 Russell King
6 *
7 * 16th March 2001 - John Ripley <jripley@sonic
8 * Fixed so that "size" is an exclusive not
9 * All users of these functions expect exclu
10 * also call with zero size.
11 * Reworked by rmk.
12 */
13 #include <linux/linkage.h>
14 #include <asm/assembler.h>
15 #include <asm/unwind.h>
16 .text
17
18 #ifdef __ARMEB__
19 #define SWAB_ENDIAN le
20 #else
21 #define SWAB_ENDIAN be
22 #endif
23
24 .macro find_first, endian, se
25 ENTRY(_find_first_\name\()bit_\endian)
26 UNWIND( .fnstart)
27 teq r1, #0
28 beq 3f
29 mov r2, #0
30 1: ldr r3, [r0], #4
31 .ifeq \set
32 mvns r3, r3
33 .else
34 movs r3, r3
35 .endif
36 .ifc \endian, SWAB_ENDIAN
37 bne .L_found_swab
38 .else
39 bne .L_found
40 .endif
41 add r2, r2, #32
42 2: cmp r2, r1
43 blo 1b
44 3: mov r0, r1
45 ret lr
46 UNWIND( .fnend)
47 ENDPROC(_find_first_\name\()bit_\endian)
48 .endm
49
50 .macro find_next, endian, set
51 ENTRY(_find_next_\name\()bit_\endian)
52 UNWIND( .fnstart)
53 cmp r2, r1
54 bhs 3b
55 mov ip, r2, lsr #5
56 add r0, r0, ip, lsl #2
57 ands ip, r2, #31
58 beq 1b
59 ldr r3, [r0], #4
60 .ifeq \set
61 mvn r3, r3
62 .endif
63 .ifc \endian, SWAB_ENDIAN
64 rev_l r3, ip
65 .if .Lrev_l_uses_tmp
66 @ we need to recompute ip beca
67 @ it.
68 and ip, r2, #31
69 .endif
70 .endif
71 movs r3, r3, lsr ip
72 bne .L_found
73 orr r2, r2, #31
74 add r2, r2, #1
75 b 2b
76 UNWIND( .fnend)
77 ENDPROC(_find_next_\name\()bit_\endian)
78 .endm
79
80 .macro find_bit, endian, set,
81 find_first \endian, \set, \nam
82 find_next \endian, \set, \nam
83 .endm
84
85 /* _find_first_zero_bit_le and _find_next_zero
86 find_bit le, 0, zero_
87
88 /* _find_first_bit_le and _find_next_bit_le */
89 find_bit le, 1
90
91 #ifdef __ARMEB__
92
93 /* _find_first_zero_bit_be and _find_next_zero
94 find_bit be, 0, zero_
95
96 /* _find_first_bit_be and _find_next_bit_be */
97 find_bit be, 1
98
99 #endif
100
101 /*
102 * One or more bits in the LSB of r3 are assum
103 */
104 .L_found_swab:
105 UNWIND( .fnstart)
106 rev_l r3, ip
107 .L_found:
108 #if __LINUX_ARM_ARCH__ >= 7
109 rbit r3, r3
110 clz r3, r3
111 add r0, r2, r3
112 #elif __LINUX_ARM_ARCH__ >= 5
113 rsb r0, r3, #0
114 and r3, r3, r0
115 clz r3, r3
116 rsb r3, r3, #31
117 add r0, r2, r3
118 #else
119 mov ip, #~0
120 tst r3, ip, lsr #16
121 addeq r2, r2, #16
122 moveq r3, r3, lsr #16
123 tst r3, #0x00ff
124 addeq r2, r2, #8
125 moveq r3, r3, lsr #8
126 tst r3, #0x000f
127 addeq r2, r2, #4
128 moveq r3, r3, lsr #4
129 tst r3, #0x0003
130 addeq r2, r2, #2
131 moveq r3, r3, lsr #2
132 tst r3, #0x0001
133 addeq r2, r2, #1
134 mov r0, r2
135 #endif
136 cmp r1, r0
137 movlo r0, r1
138 ret lr
139 UNWIND( .fnend)
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