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96cf5185 G |
1 | /* |
2 | * linux/arch/unicore32/lib/findbit.S | |
3 | * | |
4 | * Code specific to PKUnity SoC and UniCore ISA | |
5 | * | |
6 | * Copyright (C) 2001-2010 GUAN Xue-tao | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | #include <linux/linkage.h> | |
13 | #include <asm/assembler.h> | |
14 | .text | |
15 | ||
16 | /* | |
17 | * Purpose : Find a 'zero' bit | |
18 | * Prototype: int find_first_zero_bit(void *addr, unsigned int maxbit); | |
19 | */ | |
e13b91c1 | 20 | ENTRY(find_first_zero_bit) |
96cf5185 G |
21 | cxor.a r1, #0 |
22 | beq 3f | |
23 | mov r2, #0 | |
24 | 1: ldb r3, [r0+], r2 >> #3 | |
25 | xor.a r3, r3, #0xff @ invert bits | |
26 | bne .L_found @ any now set - found zero bit | |
27 | add r2, r2, #8 @ next bit pointer | |
28 | 2: csub.a r2, r1 @ any more? | |
29 | bub 1b | |
30 | 3: mov r0, r1 @ no free bits | |
31 | mov pc, lr | |
e13b91c1 | 32 | ENDPROC(find_first_zero_bit) |
96cf5185 G |
33 | |
34 | /* | |
35 | * Purpose : Find next 'zero' bit | |
36 | * Prototype: int find_next_zero_bit | |
37 | * (void *addr, unsigned int maxbit, int offset) | |
38 | */ | |
e13b91c1 | 39 | ENTRY(find_next_zero_bit) |
96cf5185 G |
40 | cxor.a r1, #0 |
41 | beq 3b | |
42 | and.a ip, r2, #7 | |
43 | beq 1b @ If new byte, goto old routine | |
44 | ldb r3, [r0+], r2 >> #3 | |
45 | xor r3, r3, #0xff @ now looking for a 1 bit | |
46 | mov.a r3, r3 >> ip @ shift off unused bits | |
47 | bne .L_found | |
48 | or r2, r2, #7 @ if zero, then no bits here | |
49 | add r2, r2, #1 @ align bit pointer | |
50 | b 2b @ loop for next bit | |
e13b91c1 | 51 | ENDPROC(find_next_zero_bit) |
96cf5185 G |
52 | |
53 | /* | |
54 | * Purpose : Find a 'one' bit | |
55 | * Prototype: int find_first_bit | |
56 | * (const unsigned long *addr, unsigned int maxbit); | |
57 | */ | |
e13b91c1 | 58 | ENTRY(find_first_bit) |
96cf5185 G |
59 | cxor.a r1, #0 |
60 | beq 3f | |
61 | mov r2, #0 | |
62 | 1: ldb r3, [r0+], r2 >> #3 | |
63 | mov.a r3, r3 | |
64 | bne .L_found @ any now set - found zero bit | |
65 | add r2, r2, #8 @ next bit pointer | |
66 | 2: csub.a r2, r1 @ any more? | |
67 | bub 1b | |
68 | 3: mov r0, r1 @ no free bits | |
69 | mov pc, lr | |
e13b91c1 | 70 | ENDPROC(find_first_bit) |
96cf5185 G |
71 | |
72 | /* | |
73 | * Purpose : Find next 'one' bit | |
74 | * Prototype: int find_next_zero_bit | |
75 | * (void *addr, unsigned int maxbit, int offset) | |
76 | */ | |
e13b91c1 | 77 | ENTRY(find_next_bit) |
96cf5185 G |
78 | cxor.a r1, #0 |
79 | beq 3b | |
80 | and.a ip, r2, #7 | |
81 | beq 1b @ If new byte, goto old routine | |
82 | ldb r3, [r0+], r2 >> #3 | |
83 | mov.a r3, r3 >> ip @ shift off unused bits | |
84 | bne .L_found | |
85 | or r2, r2, #7 @ if zero, then no bits here | |
86 | add r2, r2, #1 @ align bit pointer | |
87 | b 2b @ loop for next bit | |
e13b91c1 | 88 | ENDPROC(find_next_bit) |
96cf5185 G |
89 | |
90 | /* | |
91 | * One or more bits in the LSB of r3 are assumed to be set. | |
92 | */ | |
93 | .L_found: | |
94 | rsub r1, r3, #0 | |
95 | and r3, r3, r1 | |
96 | cntlz r3, r3 | |
97 | rsub r3, r3, #31 | |
98 | add r0, r2, r3 | |
99 | mov pc, lr | |
100 |