1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * linux/arch/arm/lib/memset.S
4 *
5 * Copyright (C) 1995-2000 Russell King
6 *
7 * ASM optimised string functions
8 */
9 #include <linux/linkage.h>
10 #include <asm/assembler.h>
11 #include <asm/unwind.h>
12
13 .text
14 .align 5
15
16 ENTRY(__memset)
17 ENTRY(mmioset)
18 WEAK(memset)
19 UNWIND( .fnstart )
20 and r1, r1, #255 @ cast to unsigned char
21 ands r3, r0, #3 @ 1 unaligned?
22 mov ip, r0 @ preserve r0 as return value
23 bne 6f @ 1
24 /*
25 * we know that the pointer in ip is aligned to a word boundary.
26 */
27 1: orr r1, r1, r1, lsl #8
28 orr r1, r1, r1, lsl #16
29 mov r3, r1
30 7: cmp r2, #16
31 blt 4f
32 UNWIND( .fnend )
33
34 #if ! CALGN(1)+0
35
36 /*
37 * We need 2 extra registers for this loop - use r8 and the LR
38 */
39 UNWIND( .fnstart )
40 UNWIND( .save {r8, lr} )
41 stmfd sp!, {r8, lr}
42 mov r8, r1
43 mov lr, r3
44
45 2: subs r2, r2, #64
46 stmiage ip!, {r1, r3, r8, lr} @ 64 bytes at a time.
47 stmiage ip!, {r1, r3, r8, lr}
48 stmiage ip!, {r1, r3, r8, lr}
49 stmiage ip!, {r1, r3, r8, lr}
50 bgt 2b
51 ldmfdeq sp!, {r8, pc} @ Now <64 bytes to go.
52 /*
53 * No need to correct the count; we're only testing bits from now on
54 */
55 tst r2, #32
56 stmiane ip!, {r1, r3, r8, lr}
57 stmiane ip!, {r1, r3, r8, lr}
58 tst r2, #16
59 stmiane ip!, {r1, r3, r8, lr}
60 ldmfd sp!, {r8, lr}
61 UNWIND( .fnend )
62
63 #else
64
65 /*
66 * This version aligns the destination pointer in order to write
67 * whole cache lines at once.
68 */
69
70 UNWIND( .fnstart )
71 UNWIND( .save {r4-r8, lr} )
72 stmfd sp!, {r4-r8, lr}
73 mov r4, r1
74 mov r5, r3
75 mov r6, r1
76 mov r7, r3
77 mov r8, r1
78 mov lr, r3
79
80 cmp r2, #96
81 tstgt ip, #31
82 ble 3f
83
84 and r8, ip, #31
85 rsb r8, r8, #32
86 sub r2, r2, r8
87 movs r8, r8, lsl #(32 - 4)
88 stmiacs ip!, {r4, r5, r6, r7}
89 stmiami ip!, {r4, r5}
90 tst r8, #(1 << 30)
91 mov r8, r1
92 strne r1, [ip], #4
93
94 3: subs r2, r2, #64
95 stmiage ip!, {r1, r3-r8, lr}
96 stmiage ip!, {r1, r3-r8, lr}
97 bgt 3b
98 ldmfdeq sp!, {r4-r8, pc}
99
100 tst r2, #32
101 stmiane ip!, {r1, r3-r8, lr}
102 tst r2, #16
103 stmiane ip!, {r4-r7}
104 ldmfd sp!, {r4-r8, lr}
105 UNWIND( .fnend )
106
107 #endif
108
109 UNWIND( .fnstart )
110 4: tst r2, #8
111 stmiane ip!, {r1, r3}
112 tst r2, #4
113 strne r1, [ip], #4
114 /*
115 * When we get here, we've got less than 4 bytes to set. We
116 * may have an unaligned pointer as well.
117 */
118 5: tst r2, #2
119 strbne r1, [ip], #1
120 strbne r1, [ip], #1
121 tst r2, #1
122 strbne r1, [ip], #1
123 ret lr
124
125 6: subs r2, r2, #4 @ 1 do we have enough
126 blt 5b @ 1 bytes to align with?
127 cmp r3, #2 @ 1
128 strblt r1, [ip], #1 @ 1
129 strble r1, [ip], #1 @ 1
130 strb r1, [ip], #1 @ 1
131 add r2, r2, r3 @ 1 (r2 = r2 - (4 - r3))
132 b 1b
133 UNWIND( .fnend )
134 ENDPROC(memset)
135 ENDPROC(mmioset)
136 ENDPROC(__memset)
137
138 ENTRY(__memset32)
139 UNWIND( .fnstart )
140 mov r3, r1 @ copy r1 to r3 and fall into memset64
141 UNWIND( .fnend )
142 ENDPROC(__memset32)
143 ENTRY(__memset64)
144 UNWIND( .fnstart )
145 mov ip, r0 @ preserve r0 as return value
146 b 7b @ jump into the middle of memset
147 UNWIND( .fnend )
148 ENDPROC(__memset64)
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