root/trunk/libffado/src/libutil/cycles.h

Revision 864, 3.2 kB (checked in by ppalmers, 13 years ago)

update license to GPLv2 or GPLv3 instead of GPLv2 or any later version. Update copyrights to reflect the new year

Line 
1 /*
2  * Copyright (C) 2005-2008 by Pieter Palmers
3  *
4  * This file is part of FFADO
5  * FFADO = Free Firewire (pro-)audio drivers for linux
6  *
7  * FFADO is based upon FreeBoB.
8  *
9  * This program is free software: you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation, either version 2 of the License, or
12  * (at your option) version 3 of the License.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
21  *
22  */
23
24 /* cycles.h
25  * Based upon cycles.h from the jackdmp package.
26  * Original Copyright:
27  *
28  *   Copyright (C) 2001 Paul Davis
29  *   Code derived from various headers from the Linux kernel
30  *
31  * This program is free software; you can redistribute it and/or modify
32  * it under the terms of the GNU General Public License as published by
33  * the Free Software Foundation; either version 2 of the License, or
34  * (at your option) version 3 of the License.
35  *
36  * This program is distributed in the hope that it will be useful,
37  * but WITHOUT ANY WARRANTY; without even the implied warranty of
38  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
39  * GNU General Public License for more details.
40  *
41  * You should have received a copy of the GNU General Public License
42  * along with this program; if not, write to the Free Software
43  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
44  *
45  */
46
47 #ifndef __FFADO_CYCLES_H__
48 #define __FFADO_CYCLES_H__
49
50 /*
51  * Standard way to access the cycle timer on i586+ CPUs.
52  * Currently only used on SMP.
53  *
54  * If you really have a SMP machine with i486 chips or older,
55  * compile for that, and this will just always return zero.
56  * That's ok, it just means that the nicer scheduling heuristics
57  * won't work for you.
58  *
59  * We only use the low 32 bits, and we'd simply better make sure
60  * that we reschedule before that wraps. Scheduling at least every
61  * four billion cycles just basically sounds like a good idea,
62  * regardless of how fast the machine is.
63  */
64
65 #ifdef __linux__
66
67 #ifdef __PPC__
68
69 /* PowerPC */
70
71 #define CPU_FTR_601            0x00000100
72
73 typedef unsigned long cycles_t;
74
75 /* For the "cycle" counter we use the timebase lower half. */
76
77 extern cycles_t cacheflush_time;
78
79 static inline cycles_t get_cycles(void)
80 {
81     cycles_t ret = 0;
82
83     __asm__ __volatile__(
84         "98:    mftb %0\n"
85         "99:\n"
86         ".section __ftr_fixup,\"a\"\n"
87         "    .long %1\n"
88         "    .long 0\n"
89         "    .long 98b\n"
90         "    .long 99b\n"
91         ".previous"
92     : "=r" (ret) : "i" (CPU_FTR_601));
93     return ret;
94 }
95
96 #endif
97
98 #ifdef __i386__
99
100 typedef unsigned long long cycles_t;
101
102 extern cycles_t cacheflush_time;
103
104 #define rdtscll(val) \
105      __asm__ __volatile__("rdtsc" : "=A" (val))
106
107 static inline cycles_t get_cycles (void)
108 {
109     unsigned long long ret;
110
111     rdtscll(ret);
112     return ret;
113 }
114
115 #endif
116
117 #endif
118
119 #endif // __FFADO_CYCLES_H__
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