summaryrefslogtreecommitdiffstats
path: root/arch/nios2/lib/memset.c
blob: 65e97802f5cc83c15703c427e61aadf28b4d5b0c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
/*
 * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
 * Copyright (C) 2004 Microtronix Datacom Ltd
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */

#include <linux/types.h>
#include <linux/string.h>

#ifdef __HAVE_ARCH_MEMSET
void *memset(void *s, int c, size_t count)
{
	int destptr, charcnt, dwordcnt, fill8reg, wrkrega;

	if (!count)
		return s;

	c &= 0xFF;

	if (count <= 8) {
		char *xs = (char *) s;

		while (count--)
			*xs++ = c;
		return s;
	}

	__asm__ __volatile__ (
		/* fill8 %3, %5 (c & 0xff) */
		"	slli	%4, %5, 8\n"
		"	or	%4, %4, %5\n"
		"	slli    %3, %4, 16\n"
		"	or	%3, %3, %4\n"
		/* Word-align %0 (s) if necessary */
		"	andi	%4, %0, 0x01\n"
		"	beq	%4, zero, 1f\n"
		"	addi	%1, %1, -1\n"
		"	stb	%3, 0(%0)\n"
		"	addi	%0, %0, 1\n"
		"1:	mov	%2, %1\n"
		/* Dword-align %0 (s) if necessary */
		"	andi	%4, %0, 0x02\n"
		"	beq	%4, zero, 2f\n"
		"	addi	%1, %1, -2\n"
		"	sth	%3, 0(%0)\n"
		"	addi	%0, %0, 2\n"
		"	mov	%2, %1\n"
		/* %1 and %2 are how many more bytes to set */
		"2:	srli	%2, %2, 2\n"
		/* %2 is how many dwords to set */
		"3:	stw	%3, 0(%0)\n"
		"	addi	%0, %0, 4\n"
		"	addi    %2, %2, -1\n"
		"	bne	%2, zero, 3b\n"
		/* store residual word and/or byte if necessary */
		"	andi	%4, %1, 0x02\n"
		"	beq	%4, zero, 4f\n"
		"	sth	%3, 0(%0)\n"
		"	addi	%0, %0, 2\n"
		/* store residual byte if necessary */
		"4:	andi	%4, %1, 0x01\n"
		"	beq	%4, zero, 5f\n"
		"	stb	%3, 0(%0)\n"
		"5:\n"
		: "=r" (destptr),	/* %0  Output */
		  "=r" (charcnt),	/* %1  Output */
		  "=r" (dwordcnt),	/* %2  Output */
		  "=r" (fill8reg),	/* %3  Output */
		  "=r" (wrkrega)	/* %4  Output */
		: "r" (c),		/* %5  Input */
		  "0" (s),		/* %0  Input/Output */
		  "1" (count)		/* %1  Input/Output */
		: "memory"		/* clobbered */
	);

	return s;
}
#endif /* __HAVE_ARCH_MEMSET */