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Aubrey.Li3f0606a2007-03-09 13:38:44 +08001/*
Aubrey Li155fd762007-04-05 18:31:18 +08002 * File: memmove.S
Aubrey.Li3f0606a2007-03-09 13:38:44 +08003 *
Aubrey Li155fd762007-04-05 18:31:18 +08004 * Copyright 2004-2007 Analog Devices Inc.
5 * Enter bugs at http://blackfin.uclinux.org/
Aubrey.Li3f0606a2007-03-09 13:38:44 +08006 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, see the file COPYING, or write
19 * to the Free Software Foundation, Inc.,
20 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23.align 2
24
25/*
26 * C Library function MEMMOVE
27 * R0 = To Address (leave unchanged to form result)
28 * R1 = From Address
29 * R2 = count
30 * Data may overlap
31 */
32
33.globl _memmove;
34_memmove:
35 I1 = P3;
36 P0 = R0; /* P0 = To address */
37 P3 = R1; /* P3 = From Address */
38 P2 = R2 ; /* P2 = count */
39 CC = P2 == 0; /* Check zero count*/
40 IF CC JUMP .Lfinished; /* very unlikely */
41
42 CC = R1 < R0 (IU); /* From < To */
43 IF !CC JUMP .Lno_overlap;
44 R3 = R1 + R2;
45 CC = R0 <= R3 (IU); /* (From+len) >= To */
46 IF CC JUMP .Loverlap;
47.Lno_overlap:
48 R3 = 11;
49 CC = R2 <= R3;
50 IF CC JUMP .Lbytes;
51 R3 = R1 | R0; /* OR addresses together */
52 R3 <<= 30; /* check bottom two bits */
53 CC = AZ; /* AZ set if zero.*/
54 IF !CC JUMP .Lbytes ; /* Jump if addrs not aligned.*/
55
56 I0 = P3;
57 P1 = P2 >> 2; /* count = n/4 */
58 P1 += -1;
59 R3 = 3;
60 R2 = R2 & R3; /* remainder */
61 P2 = R2; /* set remainder */
62 R1 = [I0++];
63
64 LSETUP (.Lquad_loop , .Lquad_loop) LC0=P1;
65.Lquad_loop: MNOP || [P0++] = R1 || R1 = [I0++];
66 [P0++] = R1;
67
68 CC = P2 == 0; /* any remaining bytes? */
69 P3 = I0; /* Ammend P3 to updated ptr. */
70 IF !CC JUMP .Lbytes;
71 P3 = I1;
72 RTS;
73
74.Lbytes: LSETUP (.Lbyte2_s , .Lbyte2_e) LC0=P2;
75.Lbyte2_s: R1 = B[P3++](Z);
76.Lbyte2_e: B[P0++] = R1;
77
78.Lfinished: P3 = I1;
79 RTS;
80
81.Loverlap:
82 P2 += -1;
83 P0 = P0 + P2;
84 P3 = P3 + P2;
85 R1 = B[P3--] (Z);
86 CC = P2 == 0;
87 IF CC JUMP .Lno_loop;
88 LSETUP (.Lol_s, .Lol_e) LC0 = P2;
89.Lol_s: B[P0--] = R1;
90.Lol_e: R1 = B[P3--] (Z);
91.Lno_loop: B[P0] = R1;
92 P3 = I1;
93 RTS;