1/*
2 * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
3 * Copyright (C) 2004 Microtronix Datacom Ltd
4 *
5 * This file is subject to the terms and conditions of the GNU General Public
6 * License.  See the file "COPYING" in the main directory of this archive
7 * for more details.
8 */
9
10#include <linux/types.h>
11#include <linux/string.h>
12
13void *memset(void *s, int c, size_t count)
14{
15	int destptr, charcnt, dwordcnt, fill8reg, wrkrega;
16
17	if (!count)
18		return s;
19
20	c &= 0xFF;
21
22	if (count <= 8) {
23		char *xs = (char *) s;
24
25		while (count--)
26			*xs++ = c;
27		return s;
28	}
29
30	__asm__ __volatile__ (
31		/* fill8 %3, %5 (c & 0xff) */
32		"	slli	%4, %5, 8\n"
33		"	or	%4, %4, %5\n"
34		"	slli    %3, %4, 16\n"
35		"	or	%3, %3, %4\n"
36		/* Word-align %0 (s) if necessary */
37		"	andi	%4, %0, 0x01\n"
38		"	beq	%4, zero, 1f\n"
39		"	addi	%1, %1, -1\n"
40		"	stb	%3, 0(%0)\n"
41		"	addi	%0, %0, 1\n"
42		"1:	mov	%2, %1\n"
43		/* Dword-align %0 (s) if necessary */
44		"	andi	%4, %0, 0x02\n"
45		"	beq	%4, zero, 2f\n"
46		"	addi	%1, %1, -2\n"
47		"	sth	%3, 0(%0)\n"
48		"	addi	%0, %0, 2\n"
49		"	mov	%2, %1\n"
50		/* %1 and %2 are how many more bytes to set */
51		"2:	srli	%2, %2, 2\n"
52		/* %2 is how many dwords to set */
53		"3:	stw	%3, 0(%0)\n"
54		"	addi	%0, %0, 4\n"
55		"	addi    %2, %2, -1\n"
56		"	bne	%2, zero, 3b\n"
57		/* store residual word and/or byte if necessary */
58		"	andi	%4, %1, 0x02\n"
59		"	beq	%4, zero, 4f\n"
60		"	sth	%3, 0(%0)\n"
61		"	addi	%0, %0, 2\n"
62		/* store residual byte if necessary */
63		"4:	andi	%4, %1, 0x01\n"
64		"	beq	%4, zero, 5f\n"
65		"	stb	%3, 0(%0)\n"
66		"5:\n"
67		: "=r" (destptr),	/* %0  Output */
68		  "=r" (charcnt),	/* %1  Output */
69		  "=r" (dwordcnt),	/* %2  Output */
70		  "=r" (fill8reg),	/* %3  Output */
71		  "=&r" (wrkrega)	/* %4  Output only */
72		: "r" (c),		/* %5  Input */
73		  "0" (s),		/* %0  Input/Output */
74		  "1" (count)		/* %1  Input/Output */
75		: "memory"		/* clobbered */
76	);
77
78	return s;
79}
80