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-rw-r--r--arch/blackfin/lib/memset.S109
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1/*
2 * File: arch/blackfin/lib/memset.S
3 * Based on:
4 * Author:
5 *
6 * Created:
7 * Description:
8 *
9 * Modified:
10 * Copyright 2004-2006 Analog Devices Inc.
11 *
12 * Bugs: Enter bugs at http://blackfin.uclinux.org/
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
18 *
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, see the file COPYING, or write
26 * to the Free Software Foundation, Inc.,
27 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
28 */
29
30#include <linux/linkage.h>
31
32.align 2
33
34#ifdef CONFIG_MEMSET_L1
35.section .l1.text
36#else
37.text
38#endif
39
40/*
41 * C Library function MEMSET
42 * R0 = address (leave unchanged to form result)
43 * R1 = filler byte
44 * R2 = count
45 * Favours word aligned data.
46 */
47
48ENTRY(_memset)
49 P0 = R0 ; /* P0 = address */
50 P2 = R2 ; /* P2 = count */
51 R3 = R0 + R2; /* end */
52 CC = R2 <= 7(IU);
53 IF CC JUMP .Ltoo_small;
54 R1 = R1.B (Z); /* R1 = fill char */
55 R2 = 3;
56 R2 = R0 & R2; /* addr bottom two bits */
57 CC = R2 == 0; /* AZ set if zero. */
58 IF !CC JUMP .Lforce_align ; /* Jump if addr not aligned. */
59
60.Laligned:
61 P1 = P2 >> 2; /* count = n/4 */
62 R2 = R1 << 8; /* create quad filler */
63 R2.L = R2.L + R1.L(NS);
64 R2.H = R2.L + R1.H(NS);
65 P2 = R3;
66
67 LSETUP (.Lquad_loop , .Lquad_loop) LC0=P1;
68.Lquad_loop:
69 [P0++] = R2;
70
71 CC = P0 == P2;
72 IF !CC JUMP .Lbytes_left;
73 RTS;
74
75.Lbytes_left:
76 R2 = R3; /* end point */
77 R3 = P0; /* current position */
78 R2 = R2 - R3; /* bytes left */
79 P2 = R2;
80
81.Ltoo_small:
82 CC = P2 == 0; /* Check zero count */
83 IF CC JUMP .Lfinished; /* Unusual */
84
85.Lbytes:
86 LSETUP (.Lbyte_loop , .Lbyte_loop) LC0=P2;
87.Lbyte_loop:
88 B[P0++] = R1;
89
90.Lfinished:
91 RTS;
92
93.Lforce_align:
94 CC = BITTST (R0, 0); /* odd byte */
95 R0 = 4;
96 R0 = R0 - R2;
97 P1 = R0;
98 R0 = P0; /* Recover return address */
99 IF !CC JUMP .Lskip1;
100 B[P0++] = R1;
101.Lskip1:
102 CC = R2 <= 2; /* 2 bytes */
103 P2 -= P1; /* reduce count */
104 IF !CC JUMP .Laligned;
105 B[P0++] = R1;
106 B[P0++] = R1;
107 JUMP .Laligned;
108
109.size _memset,.-_memset