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annotate packages/kernel/current/src/sync/flag.cxx @ 210:d2c90368aeef
Merge from eCos master repository on 2002-05-23-21:39:14-BST
| author | jlarmour |
|---|---|
| date | Thu, 23 May 2002 22:59:51 +0000 |
| parents | e0c0827131d1 |
| children | 74dbf4c3f2e1 |
| rev | line source |
|---|---|
| 0 | 1 //========================================================================== |
| 2 // | |
| 2 | 3 // flag.cxx |
| 0 | 4 // |
| 2 | 5 // Flag class implementation |
| 0 | 6 // |
| 7 //========================================================================== | |
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8 //####ECOSGPLCOPYRIGHTBEGIN#### |
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9 // ------------------------------------------- |
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10 // This file is part of eCos, the Embedded Configurable Operating System. |
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11 // Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc. |
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12 // |
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13 // eCos is free software; you can redistribute it and/or modify it under |
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14 // the terms of the GNU General Public License as published by the Free |
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15 // Software Foundation; either version 2 or (at your option) any later version. |
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16 // |
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17 // eCos is distributed in the hope that it will be useful, but WITHOUT ANY |
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18 // WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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19 // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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20 // for more details. |
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21 // |
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22 // You should have received a copy of the GNU General Public License along |
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23 // with eCos; if not, write to the Free Software Foundation, Inc., |
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24 // 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. |
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25 // |
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26 // As a special exception, if other files instantiate templates or use macros |
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27 // or inline functions from this file, or you compile this file and link it |
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28 // with other works to produce a work based on this file, this file does not |
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29 // by itself cause the resulting work to be covered by the GNU General Public |
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30 // License. However the source code for this file must still be made available |
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31 // in accordance with section (3) of the GNU General Public License. |
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32 // |
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33 // This exception does not invalidate any other reasons why a work based on |
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34 // this file might be covered by the GNU General Public License. |
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35 // |
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36 // Alternative licenses for eCos may be arranged by contacting Red Hat, Inc. |
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37 // at http://sources.redhat.com/ecos/ecos-license/ |
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38 // ------------------------------------------- |
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39 //####ECOSGPLCOPYRIGHTEND#### |
| 0 | 40 //========================================================================== |
| 41 //#####DESCRIPTIONBEGIN#### | |
| 42 // | |
| 2 | 43 // Author(s): hmt |
| 44 // Contributors: hmt | |
| 45 // Date: 1998-02-11 | |
| 46 // Purpose: Flag implementation | |
| 47 // Description: This file contains the implementations of the flag class | |
| 0 | 48 // |
| 49 //####DESCRIPTIONEND#### | |
| 50 // | |
| 51 //========================================================================== | |
| 52 | |
| 53 #include <pkgconf/kernel.h> | |
| 54 | |
| 55 #include <cyg/kernel/ktypes.h> // base kernel types | |
| 56 #include <cyg/infra/cyg_trac.h> // tracing macros | |
| 57 #include <cyg/infra/cyg_ass.h> // assertion macros | |
| 58 #include <cyg/kernel/instrmnt.h> // instrumentation | |
| 59 | |
| 60 #include <cyg/kernel/thread.inl> // thread inlines | |
| 61 | |
| 62 #include <cyg/kernel/flag.hxx> // our own header | |
| 63 | |
| 64 #include <cyg/kernel/sched.inl> // scheduler inlines | |
| 65 #include <cyg/kernel/clock.inl> // clock inlines | |
| 66 | |
| 67 // ------------------------------------------------------------------------- | |
| 68 // Constructor | |
| 69 | |
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70 Cyg_Flag::Cyg_Flag( Cyg_FlagValue init ) |
| 0 | 71 { |
| 72 CYG_REPORT_FUNCTION(); | |
| 73 value = init; | |
| 74 CYG_REPORT_RETURN(); | |
| 75 } | |
| 76 | |
| 77 // ------------------------------------------------------------------------- | |
| 78 // Destructor | |
| 79 | |
| 80 Cyg_Flag::~Cyg_Flag() | |
| 81 { | |
| 82 CYG_REPORT_FUNCTION(); | |
| 83 #if 0 | |
| 84 CYG_ASSERT( queue.empty(), "Deleting flag with threads waiting"); | |
| 85 #endif | |
| 86 // Prevent preemption | |
| 87 Cyg_Scheduler::lock(); | |
| 88 | |
| 89 while ( ! queue.empty() ) { | |
| 90 Cyg_Thread *thread = queue.dequeue(); | |
| 91 thread->set_wake_reason( Cyg_Thread::DESTRUCT ); | |
| 92 thread->wake(); | |
| 93 } | |
| 94 | |
| 95 // Unlock the scheduler and maybe switch threads | |
| 96 Cyg_Scheduler::unlock(); | |
| 97 CYG_REPORT_RETURN(); | |
| 98 } | |
| 99 | |
| 100 // ------------------------------------------------------------------------- | |
| 101 // debugging/assert function | |
| 102 | |
| 103 #ifdef CYGDBG_USE_ASSERTS | |
| 104 cyg_bool | |
| 2 | 105 Cyg_Flag::check_this(cyg_assert_class_zeal zeal) const |
| 0 | 106 { |
| 107 CYG_REPORT_FUNCTION(); | |
| 108 | |
| 109 if ( Cyg_Thread::DESTRUCT == Cyg_Thread::self()->get_wake_reason() ) | |
| 110 // then the whole thing is invalid, and we know it. | |
| 111 // so return OK, since this check should NOT make an error. | |
| 112 return true; | |
| 113 | |
| 114 // check that we have a non-NULL pointer first | |
| 115 if( this == NULL ) { | |
| 116 CYG_REPORT_RETVAL( false ); | |
| 117 return false; | |
| 118 } | |
| 119 | |
| 120 // there ain't a lot to check here. | |
| 121 CYG_REPORT_RETVAL( true ); | |
| 122 return true; | |
| 123 } | |
| 124 #endif | |
| 125 | |
| 126 // ------------------------------------------------------------------------- | |
| 127 // now the members themselves: | |
| 128 | |
| 129 // clear some bits in the value (all of them by default) by ANDing with the | |
| 130 // argument. This cannot make a wait condition become true, so there's not | |
| 131 // much to it. | |
| 132 void | |
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133 Cyg_Flag::maskbits( Cyg_FlagValue arg ) |
| 0 | 134 { |
| 135 CYG_REPORT_FUNCTION(); | |
| 136 | |
| 137 // Prevent preemption | |
| 138 Cyg_Scheduler::lock(); | |
| 139 | |
| 140 value &= arg; | |
| 141 // no need to wake anyone up; no waiter can become valid in | |
| 142 // consequence of this operation. | |
| 143 | |
| 144 // Unlock scheduler and allow other threads to run | |
| 145 Cyg_Scheduler::unlock(); | |
| 146 CYG_REPORT_RETURN(); | |
| 147 } | |
| 148 | |
| 149 | |
| 150 // ------------------------------------------------------------------------- | |
| 151 // set some bits in the value (all of them by default) and wake up any | |
| 152 // affected waiting threads; we do the decision making here so as to get | |
| 153 // atomicity wrt the other threads waking up - the value might have changed | |
| 154 // by the time they get to run. | |
| 155 | |
| 156 void | |
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157 Cyg_Flag::setbits( Cyg_FlagValue arg ) |
| 0 | 158 { |
| 159 CYG_REPORT_FUNCTION(); | |
| 160 CYG_ASSERTCLASS( this, "Bad this pointer"); | |
| 161 | |
| 162 // Prevent preemption | |
| 163 Cyg_Scheduler::lock(); | |
| 164 | |
| 165 // OR in the argument to get a new flag value. | |
| 166 value |= arg; | |
| 167 | |
| 168 // anyone waiting? | |
| 169 if ( !(queue.empty()) ) { | |
| 170 FlagWaitInfo *p; | |
| 171 Cyg_Thread *thread; | |
| 172 Cyg_ThreadQueue holding; | |
| 173 | |
| 174 do { | |
| 175 thread = queue.dequeue(); | |
| 176 p = (FlagWaitInfo *)(thread->get_wait_info()); | |
| 177 | |
| 178 CYG_ASSERT( (p->allmask == 0) != (p->anymask == 0), | |
| 179 "Both masks set" ); | |
| 180 CYG_ASSERT( 0 == p->value_out, "Thread already awoken?" ); | |
| 181 | |
| 182 if ( ((p->allmask != 0) && (p->allmask & value) == p->allmask) || | |
| 183 ((p->anymask & value) != 0 ) ) { | |
| 184 // success! awaken the thread | |
| 185 thread->set_wake_reason( Cyg_Thread::DONE ); | |
| 186 thread->wake(); | |
| 187 // return the successful value to it | |
| 188 p->value_out = value; | |
| 189 // do we clear the value; is this the end? | |
| 190 if ( p->do_clear ) { | |
| 191 // we can break here but need to preserve ordering | |
| 192 value = 0; | |
| 193 // so let it cycle the whole queue regardless | |
| 194 } | |
| 195 } | |
| 196 else { | |
| 197 // preserve the entry on the holding queue | |
| 198 holding.enqueue( thread ); | |
| 199 } | |
| 200 } while ( !(queue.empty()) ); | |
| 201 | |
| 202 // Now re-queue the unaffected threads back into the flag queue | |
| 203 while ( !(holding.empty()) ) { | |
| 204 queue.enqueue( holding.dequeue() ); | |
| 205 } | |
| 206 } | |
| 207 // Unlock scheduler and allow other threads to run | |
| 208 Cyg_Scheduler::unlock(); | |
| 209 CYG_REPORT_RETURN(); | |
| 210 } | |
| 211 | |
| 212 // ------------------------------------------------------------------------- | |
| 213 // Wait for a match on our pattern, according to the flags given. | |
| 214 // Return the matching value. | |
| 215 Cyg_FlagValue | |
| 216 Cyg_Flag::wait( Cyg_FlagValue pattern, WaitMode mode ) | |
| 217 { | |
| 218 CYG_REPORT_FUNCTION(); | |
| 219 CYG_ASSERTCLASS( this, "Bad this pointer"); | |
| 220 CYG_ASSERT( Cyg_Flag::MASK >= mode, "Bad mode" ); | |
| 221 | |
| 222 Cyg_FlagValue result; | |
| 223 | |
| 224 // Prevent preemption so that we compare atomically | |
| 225 Cyg_Scheduler::lock(); | |
| 226 | |
| 227 // try the current value | |
| 228 result = poll( pattern, mode ); | |
| 229 | |
| 230 if ( 0 != result ) { | |
| 231 Cyg_Scheduler::unlock(); | |
| 232 CYG_REPORT_RETVAL( result ); | |
| 233 return result; // all done | |
| 234 } | |
| 235 | |
| 236 // we have to wait until we are awoken | |
| 237 Cyg_Thread *self = Cyg_Thread::self(); | |
| 238 | |
| 239 FlagWaitInfo saveme; | |
| 240 saveme.allmask = (Cyg_Flag::OR & mode) ? 0 : pattern; | |
| 241 saveme.anymask = (Cyg_Flag::OR & mode) ? pattern : 0; | |
| 242 saveme.do_clear = (0 != (Cyg_Flag::CLR & mode)); | |
| 243 | |
| 244 self->set_wait_info( (CYG_ADDRWORD)&saveme ); | |
| 245 | |
| 246 result = true; // just being used as an early-out flag now | |
| 247 // this loop allows us to deal correctly with spurious wakeups | |
| 248 while ( result && (0 == saveme.value_out) ) { | |
| 249 self->set_sleep_reason( Cyg_Thread::WAIT ); | |
| 250 self->sleep(); | |
| 251 // keep track of myself on the queue of waiting threads | |
| 252 queue.enqueue( self ); | |
| 253 | |
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254 // Allow other threads to run |
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255 Cyg_Scheduler::reschedule(); |
| 0 | 256 |
| 257 CYG_ASSERT( ((CYG_ADDRWORD)&saveme) == | |
| 258 Cyg_Thread::self()->get_wait_info(), | |
| 259 "Wait info lost" ); | |
| 260 | |
| 261 switch( self->get_wake_reason() ) | |
| 262 { | |
| 263 case Cyg_Thread::DESTRUCT: | |
| 264 case Cyg_Thread::BREAK: | |
| 265 result = false; | |
| 266 break; | |
| 267 | |
| 268 case Cyg_Thread::EXIT: | |
| 269 self->exit(); | |
| 270 break; | |
| 271 | |
| 272 default: | |
| 273 break; | |
| 274 } | |
| 275 } | |
| 276 | |
| 277 CYG_ASSERT( (false == result) ^ (0 != saveme.value_out), | |
| 278 "Break out but also good result!" ); | |
| 279 | |
| 280 // Unlock scheduler and allow other threads to run | |
| 281 Cyg_Scheduler::unlock(); | |
| 282 CYG_REPORT_RETVAL( saveme.value_out ); | |
| 283 return saveme.value_out; | |
| 284 } | |
| 285 | |
| 286 // ------------------------------------------------------------------------- | |
| 287 // Wait for a match on our pattern, with a timeout. | |
| 288 // Return the matching value, or zero if timed out. | |
| 289 // (zero cannot match any pattern). | |
| 290 #ifdef CYGFUN_KERNEL_THREADS_TIMER | |
| 291 Cyg_FlagValue | |
| 292 Cyg_Flag::wait( Cyg_FlagValue pattern, WaitMode mode, | |
| 293 cyg_tick_count abs_timeout ) | |
| 294 { | |
| 295 CYG_REPORT_FUNCTION(); | |
| 296 CYG_ASSERTCLASS( this, "Bad this pointer"); | |
| 297 CYG_ASSERT( Cyg_Flag::MASK >= mode, "Bad mode" ); | |
| 298 | |
| 299 Cyg_FlagValue result; | |
| 300 | |
| 301 // Prevent preemption so that we compare atomically | |
| 302 Cyg_Scheduler::lock(); | |
| 303 | |
| 304 // try the current value | |
| 305 result = poll( pattern, mode ); | |
| 306 | |
| 307 if ( 0 != result ) { | |
| 308 Cyg_Scheduler::unlock(); | |
| 309 CYG_REPORT_RETVAL( result ); | |
| 310 return result; // all done | |
| 311 } | |
| 312 | |
| 313 // we have to wait until we are awoken | |
| 314 Cyg_Thread *self = Cyg_Thread::self(); | |
| 315 | |
| 316 FlagWaitInfo saveme; | |
| 317 saveme.allmask = (Cyg_Flag::OR & mode) ? 0 : pattern; | |
| 318 saveme.anymask = (Cyg_Flag::OR & mode) ? pattern : 0; | |
| 319 saveme.do_clear = (0 != (Cyg_Flag::CLR & mode)); | |
| 320 | |
| 321 self->set_wait_info( (CYG_ADDRWORD)&saveme ); | |
| 322 | |
| 323 // Set the timer _once_ outside the loop. | |
| 324 self->set_timer( abs_timeout, Cyg_Thread::TIMEOUT ); | |
| 325 | |
| 326 // If the timeout was in the past, it will have changed the value | |
| 327 // of wake_reason, so avoid going into the loop. | |
| 328 if( self->get_wake_reason() != Cyg_Thread::NONE ) | |
| 329 result = false; | |
| 330 else result = true; | |
| 331 | |
| 332 // Result is just being used as an early-out flag now. This loop | |
| 333 // allows us to deal correctly with spurious wakeups. | |
| 334 | |
| 335 while ( result && (0 == saveme.value_out) ) { | |
| 336 self->set_sleep_reason( Cyg_Thread::TIMEOUT ); | |
| 337 self->sleep(); | |
| 338 // keep track of myself on the queue of waiting threads | |
| 339 queue.enqueue( self ); | |
| 340 | |
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341 // Allow other threads to run |
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342 Cyg_Scheduler::reschedule(); |
| 0 | 343 |
| 344 CYG_ASSERT( ((CYG_ADDRWORD)&saveme) == | |
| 345 Cyg_Thread::self()->get_wait_info(), | |
| 346 "Wait info lost" ); | |
| 347 | |
| 348 switch( self->get_wake_reason() ) | |
| 349 { | |
| 350 case Cyg_Thread::TIMEOUT: | |
| 351 result = false; | |
| 352 break; | |
| 353 | |
| 354 case Cyg_Thread::DESTRUCT: | |
| 355 case Cyg_Thread::BREAK: | |
| 356 result = false; | |
| 357 break; | |
| 358 | |
| 359 case Cyg_Thread::EXIT: | |
| 360 self->exit(); | |
| 361 break; | |
| 362 | |
| 363 default: | |
| 364 break; | |
| 365 } | |
| 366 } | |
| 367 | |
| 368 CYG_ASSERT( (false == result) ^ (0 != saveme.value_out), | |
| 369 "Break out but also good result!" ); | |
| 370 | |
| 371 // clear the timer; if it actually fired, no worries. | |
| 372 self->clear_timer(); | |
| 373 | |
| 374 // Unlock scheduler and allow other threads to run | |
| 375 Cyg_Scheduler::unlock(); | |
| 376 // in this version, value_out might be zero meaning timed out. | |
| 377 CYG_REPORT_RETVAL( saveme.value_out ); | |
| 378 return saveme.value_out; | |
| 379 } | |
| 380 #endif // CYGFUN_KERNEL_THREADS_TIMER | |
| 381 | |
| 382 // ------------------------------------------------------------------------- | |
| 383 // Test for a match on our pattern, according to the flags given. | |
| 384 // Return the matching value if success, else zero. | |
| 385 Cyg_FlagValue | |
| 386 Cyg_Flag::poll( Cyg_FlagValue pattern, WaitMode mode ) | |
| 387 { | |
| 388 CYG_REPORT_FUNCTION(); | |
| 389 CYG_ASSERTCLASS( this, "Bad this pointer"); | |
| 390 CYG_ASSERT( Cyg_Flag::MASK >= mode, "Bad mode" ); | |
| 391 | |
| 392 // Prevent preemption so that we compare atomically | |
| 393 Cyg_Scheduler::lock(); | |
| 394 | |
| 395 Cyg_FlagValue result = 0; | |
| 396 | |
| 397 if ( Cyg_Flag::OR & mode ) { | |
| 398 if ( 0 != (value & pattern) ) | |
| 399 result = value; | |
| 400 } | |
| 401 else { // Cyg_Flag::AND - all must be set | |
| 402 if ( (pattern != 0) && (pattern == (value & pattern)) ) | |
| 403 result = value; | |
| 404 } | |
| 405 | |
| 406 // result != 0 <=> test passed | |
| 407 if ( result && (Cyg_Flag::CLR & mode) ) | |
| 408 value = 0; | |
| 409 | |
| 410 Cyg_Scheduler::unlock(); | |
| 411 | |
| 412 CYG_REPORT_RETVAL( result ); | |
| 413 return result; | |
| 414 } | |
| 415 | |
| 416 | |
| 417 // ------------------------------------------------------------------------- | |
| 418 // EOF flag.cxx |