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3f0606ad | 1 | /* |
155fd766 | 2 | * File: memcmp.S |
3f0606ad | 3 | * |
155fd766 AL |
4 | * Copyright 2004-2007 Analog Devices Inc. |
5 | * Enter bugs at http://blackfin.uclinux.org/ | |
3f0606ad AL |
6 | * |
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 MEMCMP | |
27 | * R0 = First Address | |
28 | * R1 = Second Address | |
29 | * R2 = count | |
30 | * Favours word aligned data. | |
31 | */ | |
32 | ||
33 | .globl _memcmp; | |
5b22163f | 34 | .type _memcmp, STT_FUNC; |
3f0606ad AL |
35 | _memcmp: |
36 | I1 = P3; | |
37 | P0 = R0; /* P0 = s1 address */ | |
38 | P3 = R1; /* P3 = s2 Address */ | |
39 | P2 = R2 ; /* P2 = count */ | |
40 | CC = R2 <= 7(IU); | |
41 | IF CC JUMP .Ltoo_small; | |
42 | I0 = R1; /* s2 */ | |
43 | R1 = R1 | R0; /* OR addresses together */ | |
44 | R1 <<= 30; /* check bottom two bits */ | |
45 | CC = AZ; /* AZ set if zero. */ | |
46 | IF !CC JUMP .Lbytes ; /* Jump if addrs not aligned. */ | |
47 | ||
48 | P1 = P2 >> 2; /* count = n/4 */ | |
49 | R3 = 3; | |
50 | R2 = R2 & R3; /* remainder */ | |
51 | P2 = R2; /* set remainder */ | |
52 | ||
53 | LSETUP (.Lquad_loop_s , .Lquad_loop_e) LC0=P1; | |
54 | .Lquad_loop_s: | |
55 | NOP; | |
56 | R0 = [P0++]; | |
57 | R1 = [I0++]; | |
58 | CC = R0 == R1; | |
59 | IF !CC JUMP .Lquad_different; | |
60 | .Lquad_loop_e: | |
61 | NOP; | |
62 | ||
63 | P3 = I0; /* s2 */ | |
64 | .Ltoo_small: | |
65 | CC = P2 == 0; /* Check zero count*/ | |
66 | IF CC JUMP .Lfinished; /* very unlikely*/ | |
67 | ||
68 | .Lbytes: | |
69 | LSETUP (.Lbyte_loop_s , .Lbyte_loop_e) LC0=P2; | |
70 | .Lbyte_loop_s: | |
71 | R1 = B[P3++](Z); /* *s2 */ | |
72 | R0 = B[P0++](Z); /* *s1 */ | |
73 | CC = R0 == R1; | |
74 | IF !CC JUMP .Ldifferent; | |
75 | .Lbyte_loop_e: | |
76 | NOP; | |
77 | ||
78 | .Ldifferent: | |
79 | R0 = R0 - R1; | |
80 | P3 = I1; | |
81 | RTS; | |
82 | ||
83 | .Lquad_different: | |
84 | /* We've read two quads which don't match. | |
85 | * Can't just compare them, because we're | |
86 | * a little-endian machine, so the MSBs of | |
87 | * the regs occur at later addresses in the | |
88 | * string. | |
89 | * Arrange to re-read those two quads again, | |
90 | * byte-by-byte. | |
91 | */ | |
92 | P0 += -4; /* back up to the start of the */ | |
93 | P3 = I0; /* quads, and increase the*/ | |
94 | P2 += 4; /* remainder count*/ | |
95 | P3 += -4; | |
96 | JUMP .Lbytes; | |
97 | ||
98 | .Lfinished: | |
99 | R0 = 0; | |
100 | P3 = I1; | |
101 | RTS; | |
5b22163f MF |
102 | |
103 | .size _memcmp, .-_memcmp |