Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[linux-2.6] / arch / blackfin / lib / memmove.S
1 /*
2  * File:         arch/blackfin/lib/memmove.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 /*
35  * C Library function MEMMOVE
36  * R0 = To Address (leave unchanged to form result)
37  * R1 = From Address
38  * R2 = count
39  * Data may overlap
40  */
41
42 ENTRY(_memmove)
43         I1 = P3;
44         P0 = R0;                  /* P0 = To address */
45         P3 = R1;                  /* P3 = From Address */
46         P2 = R2;                  /* P2 = count */
47         CC = P2 == 0;             /* Check zero count*/
48         IF CC JUMP .Lfinished;    /* very unlikely */
49
50         CC = R1 < R0 (IU);        /* From < To */
51         IF !CC JUMP .Lno_overlap;
52         R3 = R1 + R2;
53         CC = R0 <= R3 (IU);       /* (From+len) >= To */
54         IF CC JUMP .Loverlap;
55 .Lno_overlap:
56         R3 = 11;
57         CC = R2 <= R3;
58         IF CC JUMP .Lbytes;
59         R3 = R1 | R0;             /* OR addresses together */
60         R3 <<= 30;                /* check bottom two bits */
61         CC =  AZ;                 /* AZ set if zero.*/
62         IF !CC JUMP .Lbytes;      /* Jump if addrs not aligned.*/
63
64         I0 = P3;
65         P1 = P2 >> 2;             /* count = n/4 */
66         P1 += -1;
67         R3 =  3;
68         R2 = R2 & R3;             /* remainder */
69         P2 = R2;                  /* set remainder */
70         R1 = [I0++];
71
72         LSETUP (.Lquad_loop, .Lquad_loop) LC0=P1;
73 .Lquad_loop: MNOP || [P0++] = R1 || R1 = [I0++];
74         [P0++] = R1;
75
76         CC = P2 == 0;             /* any remaining bytes? */
77         P3 = I0;                  /* Ammend P3 to updated ptr. */
78         IF !CC JUMP .Lbytes;
79         P3 = I1;
80         RTS;
81
82 .Lbytes:     LSETUP (.Lbyte2_s, .Lbyte2_e) LC0=P2;
83 .Lbyte2_s:   R1 = B[P3++](Z);
84 .Lbyte2_e:   B[P0++] = R1;
85
86 .Lfinished:  P3 = I1;
87         RTS;
88
89 .Loverlap:
90         P2 += -1;
91         P0 = P0 + P2;
92         P3 = P3 + P2;
93         R1 = B[P3--] (Z);
94         CC = P2 == 0;
95         IF CC JUMP .Lno_loop;
96         LSETUP (.Lol_s, .Lol_e) LC0 = P2;
97 .Lol_s:    B[P0--] = R1;
98 .Lol_e:    R1 = B[P3--] (Z);
99 .Lno_loop: B[P0] = R1;
100         P3 = I1;
101         RTS;
102
103 .size _memmove,.-_memmove