1 /* SPDX-License-Identifier: GPL-2.0 */ <<
2 /* 1 /*
3 * arch/alpha/lib/strchr.S 2 * arch/alpha/lib/strchr.S
4 * Contributed by Richard Henderson (rth@tamu. 3 * Contributed by Richard Henderson (rth@tamu.edu)
5 * 4 *
6 * Return the address of a given character wit 5 * Return the address of a given character within a null-terminated
7 * string, or null if it is not found. 6 * string, or null if it is not found.
8 */ 7 */
9 #include <linux/export.h> !! 8
10 #include <asm/regdef.h> 9 #include <asm/regdef.h>
11 10
12 .set noreorder 11 .set noreorder
13 .set noat 12 .set noat
14 13
15 .align 3 14 .align 3
16 .globl strchr 15 .globl strchr
17 .ent strchr 16 .ent strchr
18 strchr: 17 strchr:
19 .frame sp, 0, ra 18 .frame sp, 0, ra
20 .prologue 0 19 .prologue 0
21 20
22 zapnot a1, 1, a1 # e0 : zero 21 zapnot a1, 1, a1 # e0 : zero extend the search character
23 ldq_u t0, 0(a0) # .. e1 : load 22 ldq_u t0, 0(a0) # .. e1 : load first quadword
24 sll a1, 8, t5 # e0 : repl 23 sll a1, 8, t5 # e0 : replicate the search character
25 andnot a0, 7, v0 # .. e1 : alig 24 andnot a0, 7, v0 # .. e1 : align our loop pointer
26 or t5, a1, a1 # e0 : 25 or t5, a1, a1 # e0 :
27 lda t4, -1 # .. e1 : buil 26 lda t4, -1 # .. e1 : build garbage mask
28 sll a1, 16, t5 # e0 : 27 sll a1, 16, t5 # e0 :
29 cmpbge zero, t0, t2 # .. e1 : bits 28 cmpbge zero, t0, t2 # .. e1 : bits set iff byte == zero
30 mskqh t4, a0, t4 # e0 : 29 mskqh t4, a0, t4 # e0 :
31 or t5, a1, a1 # .. e1 : 30 or t5, a1, a1 # .. e1 :
32 sll a1, 32, t5 # e0 : 31 sll a1, 32, t5 # e0 :
33 cmpbge zero, t4, t4 # .. e1 : bits 32 cmpbge zero, t4, t4 # .. e1 : bits set iff byte is garbage
34 or t5, a1, a1 # e0 : 33 or t5, a1, a1 # e0 :
35 xor t0, a1, t1 # .. e1 : make 34 xor t0, a1, t1 # .. e1 : make bytes == c zero
36 cmpbge zero, t1, t3 # e0 : bits 35 cmpbge zero, t1, t3 # e0 : bits set iff byte == c
37 or t2, t3, t0 # e1 : bits 36 or t2, t3, t0 # e1 : bits set iff char match or zero match
38 andnot t0, t4, t0 # e0 : clea 37 andnot t0, t4, t0 # e0 : clear garbage bits
39 bne t0, $found # .. e1 (zdb) 38 bne t0, $found # .. e1 (zdb)
40 39
41 $loop: ldq t0, 8(v0) # e0 : 40 $loop: ldq t0, 8(v0) # e0 :
42 addq v0, 8, v0 # .. e1 : 41 addq v0, 8, v0 # .. e1 :
43 nop # e0 : 42 nop # e0 :
44 xor t0, a1, t1 # .. e1 (ev5 d 43 xor t0, a1, t1 # .. e1 (ev5 data stall)
45 cmpbge zero, t0, t2 # e0 : bits 44 cmpbge zero, t0, t2 # e0 : bits set iff byte == 0
46 cmpbge zero, t1, t3 # .. e1 : bits 45 cmpbge zero, t1, t3 # .. e1 : bits set iff byte == c
47 or t2, t3, t0 # e0 : 46 or t2, t3, t0 # e0 :
48 beq t0, $loop # .. e1 (zdb) 47 beq t0, $loop # .. e1 (zdb)
49 48
50 $found: negq t0, t1 # e0 : clea 49 $found: negq t0, t1 # e0 : clear all but least set bit
51 and t0, t1, t0 # e1 (stall) 50 and t0, t1, t0 # e1 (stall)
52 51
53 and t0, t3, t1 # e0 : bit 52 and t0, t3, t1 # e0 : bit set iff byte was the char
54 beq t1, $retnull # .. e1 (zdb) 53 beq t1, $retnull # .. e1 (zdb)
55 54
56 and t0, 0xf0, t2 # e0 : bina 55 and t0, 0xf0, t2 # e0 : binary search for that set bit
57 and t0, 0xcc, t3 # .. e1 : 56 and t0, 0xcc, t3 # .. e1 :
58 and t0, 0xaa, t4 # e0 : 57 and t0, 0xaa, t4 # e0 :
59 cmovne t2, 4, t2 # .. e1 : 58 cmovne t2, 4, t2 # .. e1 :
60 cmovne t3, 2, t3 # e0 : 59 cmovne t3, 2, t3 # e0 :
61 cmovne t4, 1, t4 # .. e1 : 60 cmovne t4, 1, t4 # .. e1 :
62 addq t2, t3, t2 # e0 : 61 addq t2, t3, t2 # e0 :
63 addq v0, t4, v0 # .. e1 : 62 addq v0, t4, v0 # .. e1 :
64 addq v0, t2, v0 # e0 : 63 addq v0, t2, v0 # e0 :
65 ret # .. e1 : 64 ret # .. e1 :
66 65
67 $retnull: 66 $retnull:
68 mov zero, v0 # e0 : 67 mov zero, v0 # e0 :
69 ret # .. e1 : 68 ret # .. e1 :
70 69
71 .end strchr 70 .end strchr
72 EXPORT_SYMBOL(strchr) <<
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