1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * arch/alpha/lib/ev67-strlen.S
4 * 21264 version by Rick Gorton <rick.gorton@al
5 *
6 * Finds length of a 0-terminated string. Opt
7 * Alpha architecture:
8 *
9 * - memory accessed as aligned quadwords
10 * - uses bcmpge to compare 8 bytes in pa
11 *
12 * Much of the information about 21264 schedul
13 * Compiler Writer's Guide for the Alpha
14 * abbreviated as 'CWG' in other comments
15 * ftp.digital.com/pub/Digital/info/semic
16 * Scheduling notation:
17 * E - either cluster
18 * U - upper subcluster; U0 - subcl
19 * L - lower subcluster; L0 - subcl
20 */
21 #include <linux/export.h>
22 .set noreorder
23 .set noat
24
25 .globl strlen
26 .ent strlen
27 .align 4
28 strlen:
29 ldq_u $1, 0($16) # L : load fir
30 lda $2, -1($31) # E :
31 insqh $2, $16, $2 # U :
32 andnot $16, 7, $0 # E :
33
34 or $2, $1, $1 # E :
35 cmpbge $31, $1, $2 # E : $2 <- b
36 nop # E :
37 bne $2, $found # U :
38
39 $loop: ldq $1, 8($0) # L :
40 addq $0, 8, $0 # E : addr +=
41 cmpbge $31, $1, $2 # E :
42 beq $2, $loop # U :
43
44 $found:
45 cttz $2, $3 # U0 :
46 addq $0, $3, $0 # E :
47 subq $0, $16, $0 # E :
48 ret $31, ($26) # L0 :
49
50 .end strlen
51 EXPORT_SYMBOL(strlen)
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.