1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Sy
4 */
5
6 /* This is optimized primarily for the ARC700.
7 It would be possible to speed up the loops
8 respective one cycle / byte by forcing doub
9 by a factor of two, and speculatively loadi
10 source 1; however, that would increase the
11 and strcmp might often terminate early. */
12
13 #include <linux/linkage.h>
14
15 ENTRY_CFI(strcmp)
16 or r2,r0,r1
17 bmsk_s r2,r2,1
18 brne r2,0,.Lcharloop
19 mov_s r12,0x01010101
20 ror r5,r12
21 .Lwordloop:
22 ld.ab r2,[r0,4]
23 ld.ab r3,[r1,4]
24 nop_s
25 sub r4,r2,r12
26 bic r4,r4,r2
27 and r4,r4,r5
28 brne r4,0,.Lfound0
29 breq r2,r3,.Lwordloop
30 #ifdef __LITTLE_ENDIAN__
31 xor r0,r2,r3 ; mask for dif
32 sub_s r1,r0,1
33 bic_s r0,r0,r1 ; mask for lea
34 sub r1,r5,r0
35 xor r0,r5,r1 ; mask for lea
36 and_s r2,r2,r0
37 and_s r3,r3,r0
38 #endif /* LITTLE ENDIAN */
39 cmp_s r2,r3
40 mov_s r0,1
41 j_s.d [blink]
42 bset.lo r0,r0,31
43
44 .balign 4
45 #ifdef __LITTLE_ENDIAN__
46 .Lfound0:
47 xor r0,r2,r3 ; mask for dif
48 or r0,r0,r4 ; or in zero i
49 sub_s r1,r0,1
50 bic_s r0,r0,r1 ; mask for lea
51 sub r1,r5,r0
52 xor r0,r5,r1 ; mask for lea
53 and_s r2,r2,r0
54 and_s r3,r3,r0
55 sub.f r0,r2,r3
56 mov.hi r0,1
57 j_s.d [blink]
58 bset.lo r0,r0,31
59 #else /* BIG ENDIAN */
60 /* The zero-detection above can mis-de
61 because of carry-propagateion from
62 We can compensate for this by check
63 This compensation is not necessary
64 get a low estimate for r2, because
65 we already have 0x00 or 0x01, which
66 when bit 7 is cleared. */
67 .balign 4
68 .Lfound0:
69 lsr r0,r4,8
70 lsr_s r1,r2
71 bic_s r2,r2,r0 ; get low esti
72 bic_s r0,r0,r1 ; <this is the
73 or_s r3,r3,r0 ; ... high est
74 cmp_s r3,r2 ; ... be indep
75 or_s r2,r2,r0 ; likewise for
76 bic_s r3,r3,r0
77 rlc r0,0 ; r0 := r2 > r
78 cmp_s r2,r3
79 j_s.d [blink]
80 bset.lo r0,r0,31
81 #endif /* ENDIAN */
82
83 .balign 4
84 .Lcharloop:
85 ldb.ab r2,[r0,1]
86 ldb.ab r3,[r1,1]
87 nop_s
88 breq r2,0,.Lcmpend
89 breq r2,r3,.Lcharloop
90 .Lcmpend:
91 j_s.d [blink]
92 sub r0,r2,r3
93 END_CFI(strcmp)
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