PageRenderTime 19ms CodeModel.GetById 11ms app.highlight 5ms RepoModel.GetById 2ms app.codeStats 0ms

/arch/arm/lib/memset.S

https://bitbucket.org/evzijst/gittest
Assembly | 80 lines | 75 code | 5 blank | 0 comment | 1 complexity | 6d896133e9523e14da9eebd73c3d7493 MD5 | raw file
 1/*
 2 *  linux/arch/arm/lib/memset.S
 3 *
 4 *  Copyright (C) 1995-2000 Russell King
 5 *
 6 * This program is free software; you can redistribute it and/or modify
 7 * it under the terms of the GNU General Public License version 2 as
 8 * published by the Free Software Foundation.
 9 *
10 *  ASM optimised string functions
11 */
12#include <linux/linkage.h>
13#include <asm/assembler.h>
14
15	.text
16	.align	5
17	.word	0
18
191:	subs	r2, r2, #4		@ 1 do we have enough
20	blt	5f			@ 1 bytes to align with?
21	cmp	r3, #2			@ 1
22	strltb	r1, [r0], #1		@ 1
23	strleb	r1, [r0], #1		@ 1
24	strb	r1, [r0], #1		@ 1
25	add	r2, r2, r3		@ 1 (r2 = r2 - (4 - r3))
26/*
27 * The pointer is now aligned and the length is adjusted.  Try doing the
28 * memzero again.
29 */
30
31ENTRY(memset)
32	ands	r3, r0, #3		@ 1 unaligned?
33	bne	1b			@ 1
34/*
35 * we know that the pointer in r0 is aligned to a word boundary.
36 */
37	orr	r1, r1, r1, lsl #8
38	orr	r1, r1, r1, lsl #16
39	mov	r3, r1
40	cmp	r2, #16
41	blt	4f
42/*
43 * We need an extra register for this loop - save the return address and
44 * use the LR
45 */
46	str	lr, [sp, #-4]!
47	mov	ip, r1
48	mov	lr, r1
49
502:	subs	r2, r2, #64
51	stmgeia	r0!, {r1, r3, ip, lr}	@ 64 bytes at a time.
52	stmgeia	r0!, {r1, r3, ip, lr}
53	stmgeia	r0!, {r1, r3, ip, lr}
54	stmgeia	r0!, {r1, r3, ip, lr}
55	bgt	2b
56	LOADREGS(eqfd, sp!, {pc})	@ Now <64 bytes to go.
57/*
58 * No need to correct the count; we're only testing bits from now on
59 */
60	tst	r2, #32
61	stmneia	r0!, {r1, r3, ip, lr}
62	stmneia	r0!, {r1, r3, ip, lr}
63	tst	r2, #16
64	stmneia	r0!, {r1, r3, ip, lr}
65	ldr	lr, [sp], #4
66
674:	tst	r2, #8
68	stmneia	r0!, {r1, r3}
69	tst	r2, #4
70	strne	r1, [r0], #4
71/*
72 * When we get here, we've got less than 4 bytes to zero.  We
73 * may have an unaligned pointer as well.
74 */
755:	tst	r2, #2
76	strneb	r1, [r0], #1
77	strneb	r1, [r0], #1
78	tst	r2, #1
79	strneb	r1, [r0], #1
80	RETINSTR(mov,pc,lr)