source: rtems/cpukit/score/src/threaddispatch.c @ 85f5c14b

4.11
Last change on this file since 85f5c14b was dcf3687, checked in by Joel Sherrill <joel.sherrill@…>, on Jan 28, 2011 at 8:24:54 PM

2011-01-28 Joel Sherrill <joel.sherrilL@…>

  • include/rtems/bspIo.h, include/rtems/concat.h, include/rtems/irq.h, score/cpu/i386/rtems/score/idtr.h, score/cpu/powerpc/rtems/powerpc/registers.h, score/src/objectidtoname.c, score/src/schedulerpriorityblock.c, score/src/schedulerpriorityschedule.c, score/src/schedulerpriorityunblock.c, score/src/schedulerpriorityyield.c, score/src/thread.c, score/src/threadchangepriority.c, score/src/threadclearstate.c, score/src/threadclose.c, score/src/threadcreateidle.c, score/src/threaddelayended.c, score/src/threaddispatch.c, score/src/threadget.c, score/src/threadhandler.c, score/src/threadinitialize.c, score/src/threadloadenv.c, score/src/threadready.c, score/src/threadreset.c, score/src/threadrestart.c, score/src/threadresume.c, score/src/threadsetpriority.c, score/src/threadsetstate.c, score/src/threadsettransient.c, score/src/threadstackallocate.c, score/src/threadstackfree.c, score/src/threadstart.c, score/src/threadstartmultitasking.c, score/src/threadsuspend.c, score/src/threadtickletimeslice.c, score/src/threadyieldprocessor.c: Fix typo where license said found in found in.
  • Property mode set to 100644
File size: 5.0 KB
Line 
1/*
2 *  Thread Handler
3 *
4 *
5 *  COPYRIGHT (c) 1989-2009.
6 *  On-Line Applications Research Corporation (OAR).
7 *
8 *  The license and distribution terms for this file may be
9 *  found in the file LICENSE in this distribution or at
10 *  http://www.rtems.com/license/LICENSE.
11 *
12 *  $Id$
13 */
14
15#if HAVE_CONFIG_H
16#include "config.h"
17#endif
18
19#include <rtems/system.h>
20#include <rtems/score/apiext.h>
21#include <rtems/score/context.h>
22#include <rtems/score/interr.h>
23#include <rtems/score/isr.h>
24#include <rtems/score/object.h>
25#include <rtems/score/priority.h>
26#include <rtems/score/states.h>
27#include <rtems/score/sysstate.h>
28#include <rtems/score/thread.h>
29#include <rtems/score/threadq.h>
30#include <rtems/score/userext.h>
31#include <rtems/score/wkspace.h>
32
33#ifndef __RTEMS_USE_TICKS_FOR_STATISTICS__
34  #include <rtems/score/timestamp.h>
35#endif
36
37/*PAGE
38 *
39 *  _Thread_Enable_dispatch
40 *
41 *  This kernel routine exits a context switch disable critical section.
42 *  This is the NOT INLINED version.
43 *
44 *  Input parameters:  NONE
45 *
46 *  Output parameters:  NONE
47 *
48 *  INTERRUPT LATENCY:
49 *    dispatch thread
50 *    no dispatch thread
51 */
52
53#if ( (defined(CPU_INLINE_ENABLE_DISPATCH) &&  \
54       (CPU_INLINE_ENABLE_DISPATCH == FALSE)) || \
55      (__RTEMS_DO_NOT_INLINE_THREAD_ENABLE_DISPATCH__ == 1) )
56void _Thread_Enable_dispatch( void )
57{
58  if ( --_Thread_Dispatch_disable_level )
59    return;
60  _Thread_Dispatch();
61}
62#endif
63
64/*PAGE
65 *
66 *  _Thread_Dispatch
67 *
68 *  This kernel routine determines if a dispatch is needed, and if so
69 *  dispatches to the heir thread.  Once the heir is running an attempt
70 *  is made to dispatch any ASRs.
71 *
72 *  ALTERNATE ENTRY POINTS:
73 *    void _Thread_Enable_dispatch();
74 *
75 *  Input parameters:  NONE
76 *
77 *  Output parameters:  NONE
78 *
79 *  INTERRUPT LATENCY:
80 *    dispatch thread
81 *    no dispatch thread
82 */
83
84void _Thread_Dispatch( void )
85{
86  Thread_Control   *executing;
87  Thread_Control   *heir;
88  ISR_Level         level;
89
90  executing   = _Thread_Executing;
91  _ISR_Disable( level );
92  while ( _Thread_Dispatch_necessary == true ) {
93    heir = _Thread_Heir;
94    _Thread_Dispatch_disable_level = 1;
95    _Thread_Dispatch_necessary = false;
96    _Thread_Executing = heir;
97
98    /*
99     *  When the heir and executing are the same, then we are being
100     *  requested to do the post switch dispatching.  This is normally
101     *  done to dispatch signals.
102     */
103    if ( heir == executing )
104      goto post_switch;
105
106    /*
107     *  Since heir and executing are not the same, we need to do a real
108     *  context switch.
109     */
110#if __RTEMS_ADA__
111    executing->rtems_ada_self = rtems_ada_self;
112    rtems_ada_self = heir->rtems_ada_self;
113#endif
114    if ( heir->budget_algorithm == THREAD_CPU_BUDGET_ALGORITHM_RESET_TIMESLICE )
115      heir->cpu_time_budget = _Thread_Ticks_per_timeslice;
116
117    _ISR_Enable( level );
118
119    #ifndef __RTEMS_USE_TICKS_FOR_STATISTICS__
120      {
121        Timestamp_Control uptime, ran;
122        _TOD_Get_uptime( &uptime );
123        _Timestamp_Subtract(
124          &_Thread_Time_of_last_context_switch,
125          &uptime,
126          &ran
127        );
128        _Timestamp_Add_to( &executing->cpu_time_used, &ran );
129        _Thread_Time_of_last_context_switch = uptime;
130      }
131    #else
132      heir->cpu_time_used++;
133    #endif
134
135    /*
136     * Switch libc's task specific data.
137     */
138    if ( _Thread_libc_reent ) {
139      executing->libc_reent = *_Thread_libc_reent;
140      *_Thread_libc_reent = heir->libc_reent;
141    }
142
143    _User_extensions_Thread_switch( executing, heir );
144
145    /*
146     *  If the CPU has hardware floating point, then we must address saving
147     *  and restoring it as part of the context switch.
148     *
149     *  The second conditional compilation section selects the algorithm used
150     *  to context switch between floating point tasks.  The deferred algorithm
151     *  can be significantly better in a system with few floating point tasks
152     *  because it reduces the total number of save and restore FP context
153     *  operations.  However, this algorithm can not be used on all CPUs due
154     *  to unpredictable use of FP registers by some compilers for integer
155     *  operations.
156     */
157
158#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
159#if ( CPU_USE_DEFERRED_FP_SWITCH != TRUE )
160    if ( executing->fp_context != NULL )
161      _Context_Save_fp( &executing->fp_context );
162#endif
163#endif
164
165    _Context_Switch( &executing->Registers, &heir->Registers );
166
167#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
168#if ( CPU_USE_DEFERRED_FP_SWITCH == TRUE )
169    if ( (executing->fp_context != NULL) &&
170         !_Thread_Is_allocated_fp( executing ) ) {
171      if ( _Thread_Allocated_fp != NULL )
172        _Context_Save_fp( &_Thread_Allocated_fp->fp_context );
173      _Context_Restore_fp( &executing->fp_context );
174      _Thread_Allocated_fp = executing;
175    }
176#else
177    if ( executing->fp_context != NULL )
178      _Context_Restore_fp( &executing->fp_context );
179#endif
180#endif
181
182    executing = _Thread_Executing;
183
184    _ISR_Disable( level );
185  }
186
187post_switch:
188  _Thread_Dispatch_disable_level = 0;
189
190  _ISR_Enable( level );
191
192  _API_extensions_Run_postswitch();
193}
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