1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * arch/alpha/lib/ev67-strchr.S
4 * 21264 version contributed by Rick Gorton <ri
5 *
6 * Return the address of a given character wit
7 * string, or null if it is not found.
8 *
9 * Much of the information about 21264 schedul
10 * Compiler Writer's Guide for the Alpha
11 * abbreviated as 'CWG' in other comments
12 * ftp.digital.com/pub/Digital/info/semic
13 * Scheduling notation:
14 * E - either cluster
15 * U - upper subcluster; U0 - subcl
16 * L - lower subcluster; L0 - subcl
17 * Try not to change the actual algorithm if p
18 */
19 #include <linux/export.h>
20 #include <asm/regdef.h>
21
22 .set noreorder
23 .set noat
24
25 .align 4
26 .globl strchr
27 .ent strchr
28 strchr:
29 .frame sp, 0, ra
30 .prologue 0
31
32 ldq_u t0, 0(a0) # L : load fir
33 and a1, 0xff, t3 # E : 00000000
34 insbl a1, 1, t5 # U : 00000000
35 insbl a1, 7, a2 # U : ch000000
36
37 insbl t3, 6, a3 # U : 00ch0000
38 or t5, t3, a1 # E : 00000000
39 andnot a0, 7, v0 # E : align ou
40 lda t4, -1 # E : build ga
41
42 mskqh t4, a0, t4 # U : only wan
43 or a2, a3, a2 # E : chch0000
44 inswl a1, 2, t5 # E : 00000000
45 inswl a1, 4, a3 # E : 0000chch
46
47 or a1, a2, a1 # E : chch0000
48 or a3, t5, t5 # E : 0000chch
49 cmpbge zero, t0, t2 # E : bits set
50 cmpbge zero, t4, t4 # E : bits set
51
52 /* This quad is _very_ serialized. Lo
53 or t5, a1, a1 # E : chchchch
54 xor t0, a1, t1 # E : make byt
55 cmpbge zero, t1, t3 # E : bits set
56 or t2, t3, t0 # E : bits set
57
58 andnot t0, t4, t0 # E : clear ga
59 cttz t0, a2 # U0 : specula
60 nop # E :
61 bne t0, $found # U :
62
63 /*
64 * Yuk. This loop is going to stall l
65 * data to be loaded. Not much can be
66 * unrolled multiple times - is that s
67 * Or would exception handling recover
68 */
69 $loop: ldq t0, 8(v0) # L : Latency=
70 addq v0, 8, v0 # E :
71 xor t0, a1, t1 # E :
72 cmpbge zero, t0, t2 # E : bits set
73
74 cmpbge zero, t1, t3 # E : bits set
75 or t2, t3, t0 # E :
76 cttz t3, a2 # U0 : specula
77 beq t0, $loop # U :
78
79 $found: negq t0, t1 # E : clear al
80 and t0, t1, t0 # E :
81 and t0, t3, t1 # E : bit set
82 addq v0, a2, v0 # E : Add in t
83
84 cmoveq t1, $31, v0 # E : Two mapp
85 nop
86 nop
87 ret # L0 :
88
89 .end strchr
90 EXPORT_SYMBOL(strchr)
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