summaryrefslogtreecommitdiff
path: root/sysdeps/sparc/sparc64/strlen.S
blob: cc15e4e3fb666109016263e0f4a02da7f16f8990 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
/* Determine the length of a string.  For SPARC v9.
   Copyright (C) 1998, 1999, 2003 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Jan Vondrak <jvon4518@ss1000.ms.mff.cuni.cz> and
                  Jakub Jelinek <jj@ultra.linux.cz>.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <sysdep.h>
#include <asm/asi.h>

	/* Normally, this uses
	   ((xword - 0x0101010101010101) & 0x8080808080808080) test
	   to find out if any byte in xword could be zero. This is fast, but
	   also gives false alarm for any byte in range 0x81-0xff. It does
	   not matter for correctness, as if this test tells us there could
	   be some zero byte, we check it byte by byte, but if bytes with
	   high bits set are common in the strings, then this will give poor
	   performance. You can #define EIGHTBIT_NOT_RARE and the algorithm
	   will use one tick slower, but more precise test
	   ((xword - 0x0101010101010101) & (~xword) & 0x8080808080808080),
	   which does not give any false alarms (but if some bits are set,
	   one cannot assume from it which bytes are zero and which are not).
	   It is yet to be measured, what is the correct default for glibc
	   in these days for an average user.
	 */

	.text
	.align		32
ENTRY(strlen)
	sethi		%hi(0x01010101), %g1		/* IEU0		Group		*/
	ldub		[%o0], %o3			/* Load				*/
	or		%g1, %lo(0x01010101), %g1	/* IEU0		Group		*/
	mov		%o0, %o1			/* IEU1				*/

	sllx		%g1, 32, %g4			/* IEU0		Group 		*/
	andcc		%o0, 7, %g0			/* IEU1				*/
	or		%g1, %g4, %g1			/* IEU0		Group		*/
	brz,pn		%o3, 13f			/* CTI+IEU1			*/

	 sllx		%g1, 7, %g4			/* IEU0		Group		*/
	bne,a,pn	%icc, 15f			/* CTI				*/
	 add		%o0, 1, %o0			/* IEU1				*/
							/* %g1 = 0x0101010101010101	*
							 * %g4 = 0x8080808080808080	*
							 * %o0 = string pointer		*
							 * %o1 = start of string	*/
1:	ldx		[%o0], %o3			/* Load		Group		*/

	add		%o0, 8, %o0			/* IEU1				*/
2:	sub		%o3, %g1, %o2			/* IEU0		Group		*/
#ifdef EIGHTBIT_NOT_RARE
	andn		%o2, %o3, %o5			/* IEU0		Group		*/
	ldxa		[%o0] ASI_PNF, %o3		/* Load				*/
	andcc		%o5, %g4, %g0			/* IEU1		Group		*/
#else
	ldxa		[%o0] ASI_PNF, %o3		/* Load				*/
	andcc		%o2, %g4, %g0			/* IEU1		Group		*/
#endif

	be,pt		%xcc, 2b			/* CTI				*/
	 add		%o0, 8, %o0			/* IEU0				*/
 	addcc		%o2, %g1, %g5			/* IEU1		Group		*/
#ifdef EIGHTBIT_NOT_RARE
	srlx		%o5, 32, %o5			/* IEU0				*/

3:	andcc		%o5, %g4, %g0			/* IEU1		Group		*/
#else
	srlx		%o2, 32, %o2			/* IEU0				*/

3:	andcc		%o2, %g4, %g0			/* IEU1		Group		*/
#endif
	be,pn		%xcc, 4f			/* CTI				*/
	 srlx		%g5, 56, %o2			/* IEU0				*/
	andcc		%o2, 0xff, %g0			/* IEU1		Group		*/

	be,pn		%icc, 12f			/* CTI				*/
	 srlx		%g5, 48, %o2			/* IEU0				*/
	andcc		%o2, 0xff, %g0			/* IEU1		Group		*/
	be,pn		%icc, 11f			/* CTI				*/

	 srlx		%g5, 40, %o2			/* IEU0				*/
	andcc		%o2, 0xff, %g0			/* IEU1		Group		*/
	be,pn		%icc, 10f			/* CTI				*/
	 srlx		%g5, 32, %o2			/* IEU0				*/

	andcc		%o2, 0xff, %g0			/* IEU1		Group		*/
	be,pn		%icc, 9f			/* CTI				*/
4:	 srlx		%g5, 24, %o2			/* IEU0				*/
	andcc		%o2, 0xff, %g0			/* IEU1		Group		*/

	be,pn		%icc, 8f			/* CTI				*/
	 srlx		%g5, 16, %o2			/* IEU0				*/
	andcc		%o2, 0xff, %g0			/* IEU1		Group		*/
	be,pn		%icc, 7f			/* CTI				*/

	 srlx		%g5, 8, %o2			/* IEU0				*/
	andcc		%o2, 0xff, %g0			/* IEU1		Group		*/
	be,pn		%icc, 6f			/* CTI				*/
	 sub		%o3, %g1, %o2			/* IEU0				*/

	andcc		%g5, 0xff, %g0			/* IEU1		Group		*/
	be,pn		%icc, 5f			/* CTI				*/
	 ldxa		[%o0] ASI_PNF, %o3		/* Load				*/
	andcc		%o2, %g4, %g0			/* IEU1		Group		*/

	be,pt		%xcc, 2b			/* CTI				*/
	 add		%o0, 8, %o0			/* IEU0				*/
	addcc		%o2, %g1, %g5			/* IEU1		Group		*/
	ba,pt		%xcc, 3b			/* CTI				*/

	 srlx		%o2, 32, %o2			/* IEU0				*/
5:	add		%o0, -9, %o0			/* IEU0		Group		*/
	retl						/* CTI+IEU1	Group		*/
	 sub		%o0, %o1, %o0			/* IEU0				*/

6:	add		%o0, -10, %o0			/* IEU0		Group		*/
	retl						/* CTI+IEU1	Group		*/
	 sub		%o0, %o1, %o0			/* IEU0				*/
7:	add		%o0, -11, %o0			/* IEU0		Group		*/

	retl						/* CTI+IEU1	Group		*/
	 sub		%o0, %o1, %o0			/* IEU0				*/
8:	add		%o0, -12, %o0			/* IEU0		Group		*/
	retl						/* CTI+IEU1	Group		*/

	 sub		%o0, %o1, %o0			/* IEU0				*/
9:	add		%o0, -13, %o0			/* IEU0		Group		*/
	retl						/* CTI+IEU1	Group		*/
	 sub		%o0, %o1, %o0			/* IEU0				*/

10:	add		%o0, -14, %o0			/* IEU0		Group		*/
	retl						/* CTI+IEU1	Group		*/
	 sub		%o0, %o1, %o0			/* IEU0				*/
11:	add		%o0, -15, %o0			/* IEU0		Group		*/

	retl						/* CTI+IEU1	Group		*/
	 sub		%o0, %o1, %o0			/* IEU0				*/
12:	add		%o0, -16, %o0			/* IEU0		Group		*/
	retl						/* CTI+IEU1	Group		*/

	 sub		%o0, %o1, %o0			/* IEU0				*/
13:	retl						/* CTI+IEU1	Group		*/
	 mov		0, %o0				/* IEU0				*/
	nop

15:	ldub		[%o0], %o3			/* Load		Group		*/
16:	andcc		%o0, 7, %g0			/* IEU1				*/
	be,pn		%icc, 1b			/* CTI				*/
	 nop						/* IEU0		Group		*/

	add		%o0, 1, %o0			/* IEU1				*/
	andcc		%o3, 0xff, %g0			/* IEU1		Group		*/
	bne,a,pt	%icc, 16b			/* CTI				*/
	 lduba		[%o0] ASI_PNF, %o3		/* Load				*/

	add		%o0, -1, %o0			/* IEU0		Group		*/
	retl						/* CTI+IEU1	Group		*/
	 sub		%o0, %o1, %o0			/* IEU0				*/
END(strlen)
libc_hidden_builtin_def (strlen)