source: rtems/cpukit/score/include/rtems/score/priority.h @ b02f920f

4.11
Last change on this file since b02f920f was b02f920f, checked in by Ralf Corsepius <ralf.corsepius@…>, on Jun 14, 2010 at 6:08:50 AM

2010-06-14 Ralf Corsépius <ralf.corsepius@…>

  • libnetworking/rtems/mkrootfs.h, posix/include/rtems/posix/pthread.h, score/include/rtems/score/coresem.h, score/include/rtems/score/priority.h, score/include/rtems/score/threadq.h, score/include/rtems/score/timestamp.h: Move 'extern "C"'.
  • Property mode set to 100644
File size: 4.4 KB
Line 
1/**
2 *  @file  rtems/score/priority.h
3 *
4 *  This include file contains all thread priority manipulation routines.
5 *  This Handler provides mechanisms which can be used to
6 *  initialize and manipulate thread priorities.
7 */
8
9/*
10 *  COPYRIGHT (c) 1989-2006.
11 *  On-Line Applications Research Corporation (OAR).
12 *
13 *  The license and distribution terms for this file may be
14 *  found in the file LICENSE in this distribution or at
15 *  http://www.rtems.com/license/LICENSE.
16 *
17 *  $Id$
18 */
19
20#ifndef _RTEMS_SCORE_PRIORITY_H
21#define _RTEMS_SCORE_PRIORITY_H
22
23/**
24 *  @defgroup ScorePriority Priority Handler
25 *
26 *  This handler encapsulates functionality which is used to manage
27 *  thread priorities.  At the SuperCore level 256 priority levels
28 *  are supported with lower numbers representing logically more important
29 *  threads.  The priority level 0 is reserved for internal RTEMS use.
30 *  Typically it is assigned to threads which defer internal RTEMS
31 *  actions from an interrupt to thread level to improve interrupt response.
32 *  Priority level 255 is assigned to the IDLE thread and really should not
33 *  be used by application threads.  The default IDLE thread implementation
34 *  is an infinite "branch to self" loop which never yields to other threads
35 *  at the same priority.
36 */
37/**@{*/
38
39/*
40 * Processor specific information.
41 */
42#include <rtems/score/cpu.h>
43
44#ifdef __cplusplus
45extern "C" {
46#endif
47
48/**
49 *  The following type defines the control block used to manage
50 *  thread priorities.
51 *
52 *  @note Priority 0 is reserved for internal threads only.
53 */
54typedef uint32_t   Priority_Control;
55
56/** This defines the highest (most important) thread priority. */
57#define PRIORITY_MINIMUM      0
58
59/** This defines the default lowest (least important) thread priority. */
60#if defined (CPU_PRIORITY_MAXIMUM)
61  #define PRIORITY_DEFAULT_MAXIMUM      CPU_PRIORITY_MAXIMUM
62#else
63  #define PRIORITY_DEFAULT_MAXIMUM      255
64#endif
65
66/** This defines the lowest (least important) thread priority. */
67#define PRIORITY_MAXIMUM      rtems_maximum_priority
68
69/**
70 *  The following record defines the information associated with
71 *  each thread to manage its interaction with the priority bit maps.
72 */
73typedef struct {
74  /** This is the address of minor bit map slot. */
75  Priority_Bit_map_control *minor;
76  /** This is the priority bit map ready mask. */
77  Priority_Bit_map_control  ready_major;
78  /** This is the priority bit map ready mask. */
79  Priority_Bit_map_control  ready_minor;
80  /** This is the priority bit map block mask. */
81  Priority_Bit_map_control  block_major;
82  /** This is the priority bit map block mask. */
83  Priority_Bit_map_control  block_minor;
84}   Priority_Information;
85
86/**
87 *  This variable contains the configured number of priorities
88 */
89extern uint8_t rtems_maximum_priority;
90
91/**
92 *  Each sixteen bit entry in this array is associated with one of
93 *  the sixteen entries in the Priority Bit map.
94 */
95SCORE_EXTERN volatile Priority_Bit_map_control _Priority_Major_bit_map;
96
97/** Each bit in the Priority Bitmap indicates whether or not there are
98 *  threads ready at a particular priority.  The mapping of
99 *  individual priority levels to particular bits is processor
100 *  dependent as is the value of each bit used to indicate that
101 *  threads are ready at that priority.
102 */
103SCORE_EXTERN Priority_Bit_map_control
104               _Priority_Bit_map[16] CPU_STRUCTURE_ALIGNMENT;
105
106/*
107 *  The definition of the Priority_Bit_map_control type is CPU dependent.
108 *
109 */
110
111#if ( CPU_USE_GENERIC_BITFIELD_CODE == FALSE )
112/**
113 *  This method returns the priority bit mask for the specified major
114 *  or minor bit number.
115 *
116 *  @param[in] _bit_number is the bit number for which we need a mask
117 *
118 *  @return the priority bit mask
119 *
120 *  @note This may simply be a pass through to a CPU dependent implementation.
121 */
122#define _Priority_Mask( _bit_number ) \
123  _CPU_Priority_Mask( _bit_number )
124#endif
125
126#if ( CPU_USE_GENERIC_BITFIELD_CODE == FALSE )
127/**
128 *  This method returns the bit index position for the specified priority.
129 *
130 *  @param[in] _priority is the priority for which we need the index.
131 *
132 *  @return This method returns the array index into the priority bit map.
133 *
134 *  @note This may simply be a pass through to a CPU dependent implementation.
135 */
136#define _Priority_Bits_index( _priority ) \
137  _CPU_Priority_bits_index( _priority )
138#endif
139
140#ifndef __RTEMS_APPLICATION__
141#include <rtems/score/priority.inl>
142#endif
143
144#ifdef __cplusplus
145}
146#endif
147
148/**@}*/
149
150#endif
151/* end of include file */
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