| blob | b5e8b9ae4c7d496dcd292e6437d3bebd6417a870 |
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@sonicblue.com>
8 * Fixed so that "size" is an exclusive not an inclusive quantity.
9 * All users of these functions expect exclusive sizes, and may
10 * also call with zero size.
11 * Reworked by rmk.
12 */
13 #include <linux/linkage.h>
14 #include <asm/assembler.h>
15 .text
17 /*
18 * Purpose : Find a 'zero' bit
19 * Prototype: int find_first_zero_bit(void *addr, unsigned int maxbit);
20 */
21 ENTRY(_find_first_zero_bit_le)
22 teq r1, #0
23 beq 3f
24 mov r2, #0
25 1:
26 ARM( ldrb r3, [r0, r2, lsr #3] )
27 THUMB( lsr r3, r2, #3 )
28 THUMB( ldrb r3, [r0, r3] )
29 eors r3, r3, #0xff @ invert bits
30 bne .L_found @ any now set - found zero bit
31 add r2, r2, #8 @ next bit pointer
32 2: cmp r2, r1 @ any more?
33 blo 1b
34 3: mov r0, r1 @ no free bits
35 ret lr
36 ENDPROC(_find_first_zero_bit_le)
38 /*
39 * Purpose : Find next 'zero' bit
40 * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
41 */
42 ENTRY(_find_next_zero_bit_le)
43 teq r1, #0
44 beq 3b
45 ands ip, r2, #7
46 beq 1b @ If new byte, goto old routine
47 ARM( ldrb r3, [r0, r2, lsr #3] )
48 THUMB( lsr r3, r2, #3 )
49 THUMB( ldrb r3, [r0, r3] )
50 eor r3, r3, #0xff @ now looking for a 1 bit
51 movs r3, r3, lsr ip @ shift off unused bits
52 bne .L_found
53 orr r2, r2, #7 @ if zero, then no bits here
54 add r2, r2, #1 @ align bit pointer
55 b 2b @ loop for next bit
56 ENDPROC(_find_next_zero_bit_le)
58 /*
59 * Purpose : Find a 'one' bit
60 * Prototype: int find_first_bit(const unsigned long *addr, unsigned int maxbit);
61 */
62 ENTRY(_find_first_bit_le)
63 teq r1, #0
64 beq 3f
65 mov r2, #0
66 1:
67 ARM( ldrb r3, [r0, r2, lsr #3] )
68 THUMB( lsr r3, r2, #3 )
69 THUMB( ldrb r3, [r0, r3] )
70 movs r3, r3
71 bne .L_found @ any now set - found zero bit
72 add r2, r2, #8 @ next bit pointer
73 2: cmp r2, r1 @ any more?
74 blo 1b
75 3: mov r0, r1 @ no free bits
76 ret lr
77 ENDPROC(_find_first_bit_le)
79 /*
80 * Purpose : Find next 'one' bit
81 * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
82 */
83 ENTRY(_find_next_bit_le)
84 teq r1, #0
85 beq 3b
86 ands ip, r2, #7
87 beq 1b @ If new byte, goto old routine
88 ARM( ldrb r3, [r0, r2, lsr #3] )
89 THUMB( lsr r3, r2, #3 )
90 THUMB( ldrb r3, [r0, r3] )
91 movs r3, r3, lsr ip @ shift off unused bits
92 bne .L_found
93 orr r2, r2, #7 @ if zero, then no bits here
94 add r2, r2, #1 @ align bit pointer
95 b 2b @ loop for next bit
96 ENDPROC(_find_next_bit_le)
98 #ifdef __ARMEB__
100 ENTRY(_find_first_zero_bit_be)
101 teq r1, #0
102 beq 3f
103 mov r2, #0
104 1: eor r3, r2, #0x18 @ big endian byte ordering
105 ARM( ldrb r3, [r0, r3, lsr #3] )
106 THUMB( lsr r3, #3 )
107 THUMB( ldrb r3, [r0, r3] )
108 eors r3, r3, #0xff @ invert bits
109 bne .L_found @ any now set - found zero bit
110 add r2, r2, #8 @ next bit pointer
111 2: cmp r2, r1 @ any more?
112 blo 1b
113 3: mov r0, r1 @ no free bits
114 ret lr
115 ENDPROC(_find_first_zero_bit_be)
117 ENTRY(_find_next_zero_bit_be)
118 teq r1, #0
119 beq 3b
120 ands ip, r2, #7
121 beq 1b @ If new byte, goto old routine
122 eor r3, r2, #0x18 @ big endian byte ordering
123 ARM( ldrb r3, [r0, r3, lsr #3] )
124 THUMB( lsr r3, #3 )
125 THUMB( ldrb r3, [r0, r3] )
126 eor r3, r3, #0xff @ now looking for a 1 bit
127 movs r3, r3, lsr ip @ shift off unused bits
128 bne .L_found
129 orr r2, r2, #7 @ if zero, then no bits here
130 add r2, r2, #1 @ align bit pointer
131 b 2b @ loop for next bit
132 ENDPROC(_find_next_zero_bit_be)
134 ENTRY(_find_first_bit_be)
135 teq r1, #0
136 beq 3f
137 mov r2, #0
138 1: eor r3, r2, #0x18 @ big endian byte ordering
139 ARM( ldrb r3, [r0, r3, lsr #3] )
140 THUMB( lsr r3, #3 )
141 THUMB( ldrb r3, [r0, r3] )
142 movs r3, r3
143 bne .L_found @ any now set - found zero bit
144 add r2, r2, #8 @ next bit pointer
145 2: cmp r2, r1 @ any more?
146 blo 1b
147 3: mov r0, r1 @ no free bits
148 ret lr
149 ENDPROC(_find_first_bit_be)
151 ENTRY(_find_next_bit_be)
152 teq r1, #0
153 beq 3b
154 ands ip, r2, #7
155 beq 1b @ If new byte, goto old routine
156 eor r3, r2, #0x18 @ big endian byte ordering
157 ARM( ldrb r3, [r0, r3, lsr #3] )
158 THUMB( lsr r3, #3 )
159 THUMB( ldrb r3, [r0, r3] )
160 movs r3, r3, lsr ip @ shift off unused bits
161 bne .L_found
162 orr r2, r2, #7 @ if zero, then no bits here
163 add r2, r2, #1 @ align bit pointer
164 b 2b @ loop for next bit
165 ENDPROC(_find_next_bit_be)
167 #endif
169 /*
170 * One or more bits in the LSB of r3 are assumed to be set.
171 */
172 .L_found:
173 #if __LINUX_ARM_ARCH__ >= 5
174 rsb r0, r3, #0
175 and r3, r3, r0
176 clz r3, r3
177 rsb r3, r3, #31
178 add r0, r2, r3
179 #else
180 tst r3, #0x0f
181 addeq r2, r2, #4
182 movne r3, r3, lsl #4
183 tst r3, #0x30
184 addeq r2, r2, #2
185 movne r3, r3, lsl #2
186 tst r3, #0x40
187 addeq r2, r2, #1
188 mov r0, r2
189 #endif
190 cmp r1, r0 @ Clamp to maxbit
191 movlo r0, r1
192 ret lr