Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/* strlen.S: Sparc optimized strlen code
2 * Hand optimized from GNU libc's strlen
3 * Copyright (C) 1991,1996 Free Software Foundation
4 * Copyright (C) 1996,2008 David S. Miller (davem@davemloft.net)
5 * Copyright (C) 1996, 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
6 */
7
8#include <linux/linkage.h>
9#include <asm/asm.h>
10#include <asm/export.h>
11
12#define LO_MAGIC 0x01010101
13#define HI_MAGIC 0x80808080
14
15 .text
16ENTRY(strlen)
17 mov %o0, %o1
18 andcc %o0, 3, %g0
19 BRANCH32(be, pt, 9f)
20 sethi %hi(HI_MAGIC), %o4
21 ldub [%o0], %o5
22 BRANCH_REG_ZERO(pn, %o5, 11f)
23 add %o0, 1, %o0
24 andcc %o0, 3, %g0
25 BRANCH32(be, pn, 4f)
26 or %o4, %lo(HI_MAGIC), %o3
27 ldub [%o0], %o5
28 BRANCH_REG_ZERO(pn, %o5, 12f)
29 add %o0, 1, %o0
30 andcc %o0, 3, %g0
31 BRANCH32(be, pt, 5f)
32 sethi %hi(LO_MAGIC), %o4
33 ldub [%o0], %o5
34 BRANCH_REG_ZERO(pn, %o5, 13f)
35 add %o0, 1, %o0
36 BRANCH32(ba, pt, 8f)
37 or %o4, %lo(LO_MAGIC), %o2
389:
39 or %o4, %lo(HI_MAGIC), %o3
404:
41 sethi %hi(LO_MAGIC), %o4
425:
43 or %o4, %lo(LO_MAGIC), %o2
448:
45 ld [%o0], %o5
462:
47 sub %o5, %o2, %o4
48 andcc %o4, %o3, %g0
49 BRANCH32(be, pt, 8b)
50 add %o0, 4, %o0
51
52 /* Check every byte. */
53 srl %o5, 24, %g7
54 andcc %g7, 0xff, %g0
55 BRANCH32(be, pn, 1f)
56 add %o0, -4, %o4
57 srl %o5, 16, %g7
58 andcc %g7, 0xff, %g0
59 BRANCH32(be, pn, 1f)
60 add %o4, 1, %o4
61 srl %o5, 8, %g7
62 andcc %g7, 0xff, %g0
63 BRANCH32(be, pn, 1f)
64 add %o4, 1, %o4
65 andcc %o5, 0xff, %g0
66 BRANCH32_ANNUL(bne, pt, 2b)
67 ld [%o0], %o5
68 add %o4, 1, %o4
691:
70 retl
71 sub %o4, %o1, %o0
7211:
73 retl
74 mov 0, %o0
7512:
76 retl
77 mov 1, %o0
7813:
79 retl
80 mov 2, %o0
81ENDPROC(strlen)
82EXPORT_SYMBOL(strlen)