Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/kaber/nf-next-2.6
[linux-2.6.git] / arch / blackfin / lib / memcmp.S
1 /*
2  * Copyright 2004-2009 Analog Devices Inc.
3  *
4  * Licensed under the ADI BSD license or the GPL-2 (or later)
5  */
6
7 #include <linux/linkage.h>
8
9 /* int memcmp(const void *s1, const void *s2, size_t n);
10  * R0 = First Address (s1)
11  * R1 = Second Address (s2)
12  * R2 = count (n)
13  *
14  * Favours word aligned data.
15  */
16
17 .text
18
19 .align 2
20
21 ENTRY(_memcmp)
22         I1 = P3;
23         P0 = R0;                        /* P0 = s1 address */
24         P3 = R1;                        /* P3 = s2 Address  */
25         P2 = R2 ;                       /* P2 = count */
26         CC = R2 <= 7(IU);
27         IF CC JUMP .Ltoo_small;
28         I0 = R1;                        /* s2 */
29         R1 = R1 | R0;           /* OR addresses together */
30         R1 <<= 30;              /* check bottom two bits */
31         CC =  AZ;                       /* AZ set if zero. */
32         IF !CC JUMP .Lbytes ;   /* Jump if addrs not aligned. */
33
34         P1 = P2 >> 2;           /* count = n/4 */
35         R3 =  3;
36         R2 = R2 & R3;           /* remainder */
37         P2 = R2;                        /* set remainder */
38
39         LSETUP (.Lquad_loop_s, .Lquad_loop_e) LC0=P1;
40 .Lquad_loop_s:
41 #if ANOMALY_05000202
42         R0 = [P0++];
43         R1 = [I0++];
44 #else
45         MNOP || R0 = [P0++] || R1 = [I0++];
46 #endif
47         CC = R0 == R1;
48         IF !CC JUMP .Lquad_different;
49 .Lquad_loop_e:
50         NOP;
51
52         P3 = I0;                        /* s2 */
53 .Ltoo_small:
54         CC = P2 == 0;           /* Check zero count*/
55         IF CC JUMP .Lfinished;  /* very unlikely*/
56
57 .Lbytes:
58         LSETUP (.Lbyte_loop_s, .Lbyte_loop_e) LC0=P2;
59 .Lbyte_loop_s:
60         R1 = B[P3++](Z);        /* *s2 */
61         R0 = B[P0++](Z);        /* *s1 */
62         CC = R0 == R1;
63         IF !CC JUMP .Ldifferent;
64 .Lbyte_loop_e:
65         NOP;
66
67 .Ldifferent:
68         R0 = R0 - R1;
69         P3 = I1;
70         RTS;
71
72 .Lquad_different:
73         /* We've read two quads which don't match.
74          * Can't just compare them, because we're
75          * a little-endian machine, so the MSBs of
76          * the regs occur at later addresses in the
77          * string.
78          * Arrange to re-read those two quads again,
79          * byte-by-byte.
80          */
81         P0 += -4;               /* back up to the start of the */
82         P3 = I0;                /* quads, and increase the*/
83         P2 += 4;                /* remainder count*/
84         P3 += -4;
85         JUMP .Lbytes;
86
87 .Lfinished:
88         R0 = 0;
89         P3 = I1;
90         RTS;
91
92 ENDPROC(_memcmp)