begriffs open source - freertos/blob - portable/IAR/RX700v3_DPFPU/port.c

   1 /*
   2  * FreeRTOS Kernel V10.4.3
   3  * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a copy of
   6  * this software and associated documentation files (the "Software"), to deal in
   7  * the Software without restriction, including without limitation the rights to
   8  * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
   9  * the Software, and to permit persons to whom the Software is furnished to do so,
  10  * subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be included in all
  13  * copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  17  * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
  18  * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
  19  * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  20  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  21  *
  22  * https://www.FreeRTOS.org
  23  * https://github.com/FreeRTOS
  24  *
  25  * 1 tab == 4 spaces!
  26  */
  27
  28 /*-----------------------------------------------------------
  29 * Implementation of functions defined in portable.h for the RXv3 DPFPU port.
  30 *----------------------------------------------------------*/
  31
  32 #warning Testing for DFPU support in this port is not yet complete
  33
  34 /* Scheduler includes. */
  35 #include "FreeRTOS.h"
  36 #include "task.h"
  37
  38 /* Library includes. */
  39 #include "string.h"
  40
  41 /* Hardware specifics. */
  42 #if ( configINCLUDE_PLATFORM_H_INSTEAD_OF_IODEFINE_H == 1 )
  43
  44     #include "platform.h"
  45
  46 #else /* configINCLUDE_PLATFORM_H_INSTEAD_OF_IODEFINE_H */
  47
  48     #include "iodefine.h"
  49
  50 #endif /* configINCLUDE_PLATFORM_H_INSTEAD_OF_IODEFINE_H */
  51
  52 /*-----------------------------------------------------------*/
  53
  54 /* Tasks should start with interrupts enabled and in Supervisor mode, therefore
  55  * PSW is set with U and I set, and PM and IPL clear. */
  56 #define portINITIAL_PSW     ( ( StackType_t ) 0x00030000 )
  57 #define portINITIAL_FPSW    ( ( StackType_t ) 0x00000100 )
  58 #define portINITIAL_DPSW    ( ( StackType_t ) 0x00000100 )
  59 #define portINITIAL_DCMR    ( ( StackType_t ) 0x00000000 )
  60 #define portINITIAL_DECNT   ( ( StackType_t ) 0x00000001 )
  61
  62 /* Tasks are not created with a DPFPU context, but can be given a DPFPU context
  63  * after they have been created.  A variable is stored as part of the tasks context
  64  * that holds portNO_DPFPU_CONTEXT if the task does not have a DPFPU context, or
  65  * any other value if the task does have a DPFPU context. */
  66 #define portNO_DPFPU_CONTEXT    ( ( StackType_t ) 0 )
  67 #define portHAS_DPFPU_CONTEXT   ( ( StackType_t ) 1 )
  68
  69 /* The space on the stack required to hold the DPFPU data registers.  This is 16
  70  * 64-bit registers. */
  71 #define portDPFPU_DATA_REGISTER_WORDS   ( 16 * 2 )
  72
  73 /*-----------------------------------------------------------*/
  74
  75 /*
  76  * Function to start the first task executing - written in asm code as direct
  77  * access to registers is required.
  78  */
  79 static void prvStartFirstTask( void );
  80
  81 /*
  82  * Software interrupt handler.  Performs the actual context switch (saving and
  83  * restoring of registers).  Written in asm code as direct register access is
  84  * required.
  85  */
  86 __interrupt void vSoftwareInterruptISR( void );
  87
  88 /*
  89  * The tick ISR handler.  The peripheral used is configured by the application
  90  * via a hook/callback function.
  91  */
  92 __interrupt void vTickISR( void );
  93
  94 /*-----------------------------------------------------------*/
  95
  96 /* Saved as part of the task context.  If ulPortTaskHasDPFPUContext is non-zero
  97  * then a DPFPU context must be saved and restored for the task. */
  98 #if ( configUSE_TASK_DPFPU_SUPPORT == 1 )
  99
 100     StackType_t ulPortTaskHasDPFPUContext = portNO_DPFPU_CONTEXT;
 101
 102 #endif /* configUSE_TASK_DPFPU_SUPPORT */
 103
 104 /* This is accessed by the inline assembler functions so is file scope for
 105  * convenience. */
 106 extern void * pxCurrentTCB;
 107 extern void vTaskSwitchContext( void );
 108
 109 /*-----------------------------------------------------------*/
 110
 111 /*
 112  * See header file for description.
 113  */
 114 StackType_t * pxPortInitialiseStack( StackType_t * pxTopOfStack,
 115                                      TaskFunction_t pxCode,
 116                                      void * pvParameters )
 117 {
 118     /* R0 is not included as it is the stack pointer. */
 119
 120     *pxTopOfStack = 0x00;
 121     pxTopOfStack--;
 122     *pxTopOfStack = portINITIAL_PSW;
 123     pxTopOfStack--;
 124     *pxTopOfStack = ( StackType_t ) pxCode;
 125
 126     /* When debugging it can be useful if every register is set to a known
 127      * value.  Otherwise code space can be saved by just setting the registers
 128      * that need to be set. */
 129     #ifdef USE_FULL_REGISTER_INITIALISATION
 130         {
 131             pxTopOfStack--;
 132             *pxTopOfStack = 0xffffffff; /* r15. */
 133             pxTopOfStack--;
 134             *pxTopOfStack = 0xeeeeeeee;
 135             pxTopOfStack--;
 136             *pxTopOfStack = 0xdddddddd;
 137             pxTopOfStack--;
 138             *pxTopOfStack = 0xcccccccc;
 139             pxTopOfStack--;
 140             *pxTopOfStack = 0xbbbbbbbb;
 141             pxTopOfStack--;
 142             *pxTopOfStack = 0xaaaaaaaa;
 143             pxTopOfStack--;
 144             *pxTopOfStack = 0x99999999;
 145             pxTopOfStack--;
 146             *pxTopOfStack = 0x88888888;
 147             pxTopOfStack--;
 148             *pxTopOfStack = 0x77777777;
 149             pxTopOfStack--;
 150             *pxTopOfStack = 0x66666666;
 151             pxTopOfStack--;
 152             *pxTopOfStack = 0x55555555;
 153             pxTopOfStack--;
 154             *pxTopOfStack = 0x44444444;
 155             pxTopOfStack--;
 156             *pxTopOfStack = 0x33333333;
 157             pxTopOfStack--;
 158             *pxTopOfStack = 0x22222222;
 159             pxTopOfStack--;
 160         }
 161     #else /* ifdef USE_FULL_REGISTER_INITIALISATION */
 162         {
 163             pxTopOfStack -= 15;
 164         }
 165     #endif /* ifdef USE_FULL_REGISTER_INITIALISATION */
 166
 167     *pxTopOfStack = ( StackType_t ) pvParameters; /* R1 */
 168     pxTopOfStack--;
 169     *pxTopOfStack = portINITIAL_FPSW;
 170     pxTopOfStack--;
 171     *pxTopOfStack = 0x11111111; /* Accumulator 1. */
 172     pxTopOfStack--;
 173     *pxTopOfStack = 0x22222222; /* Accumulator 1. */
 174     pxTopOfStack--;
 175     *pxTopOfStack = 0x33333333; /* Accumulator 1. */
 176     pxTopOfStack--;
 177     *pxTopOfStack = 0x44444444; /* Accumulator 0. */
 178     pxTopOfStack--;
 179     *pxTopOfStack = 0x55555555; /* Accumulator 0. */
 180     pxTopOfStack--;
 181     *pxTopOfStack = 0x66666666; /* Accumulator 0. */
 182
 183     #if ( configUSE_TASK_DPFPU_SUPPORT == 1 )
 184         {
 185             /* The task will start without a DPFPU context.  A task that
 186              * uses the DPFPU hardware must call vPortTaskUsesDPFPU() before
 187              * executing any floating point instructions. */
 188             pxTopOfStack--;
 189             *pxTopOfStack = portNO_DPFPU_CONTEXT;
 190         }
 191     #elif ( configUSE_TASK_DPFPU_SUPPORT == 2 )
 192         {
 193             /* The task will start with a DPFPU context.  Leave enough
 194              * space for the registers - and ensure they are initialised if desired. */
 195             #ifdef USE_FULL_REGISTER_INITIALISATION
 196                 {
 197                     pxTopOfStack -= 2;
 198                     *(double *)pxTopOfStack = 1515.1515; /* DR15. */
 199                     pxTopOfStack -= 2;
 200                     *(double *)pxTopOfStack = 1414.1414; /* DR14. */
 201                     pxTopOfStack -= 2;
 202                     *(double *)pxTopOfStack = 1313.1313; /* DR13. */
 203                     pxTopOfStack -= 2;
 204                     *(double *)pxTopOfStack = 1212.1212; /* DR12. */
 205                     pxTopOfStack -= 2;
 206                     *(double *)pxTopOfStack = 1111.1111; /* DR11. */
 207                     pxTopOfStack -= 2;
 208                     *(double *)pxTopOfStack = 1010.1010; /* DR10. */
 209                     pxTopOfStack -= 2;
 210                     *(double *)pxTopOfStack =  909.0909; /* DR9. */
 211                     pxTopOfStack -= 2;
 212                     *(double *)pxTopOfStack =  808.0808; /* DR8. */
 213                     pxTopOfStack -= 2;
 214                     *(double *)pxTopOfStack =  707.0707; /* DR7. */
 215                     pxTopOfStack -= 2;
 216                     *(double *)pxTopOfStack =  606.0606; /* DR6. */
 217                     pxTopOfStack -= 2;
 218                     *(double *)pxTopOfStack =  505.0505; /* DR5. */
 219                     pxTopOfStack -= 2;
 220                     *(double *)pxTopOfStack =  404.0404; /* DR4. */
 221                     pxTopOfStack -= 2;
 222                     *(double *)pxTopOfStack =  303.0303; /* DR3. */
 223                     pxTopOfStack -= 2;
 224                     *(double *)pxTopOfStack =  202.0202; /* DR2. */
 225                     pxTopOfStack -= 2;
 226                     *(double *)pxTopOfStack =  101.0101; /* DR1. */
 227                     pxTopOfStack -= 2;
 228                     *(double *)pxTopOfStack = 9876.54321;/* DR0. */
 229                 }
 230             #else /* ifdef USE_FULL_REGISTER_INITIALISATION */
 231                 {
 232                     pxTopOfStack -= portDPFPU_DATA_REGISTER_WORDS;
 233                     memset( pxTopOfStack, 0x00, portDPFPU_DATA_REGISTER_WORDS * sizeof( StackType_t ) );
 234                 }
 235             #endif /* ifdef USE_FULL_REGISTER_INITIALISATION */
 236             pxTopOfStack--;
 237             *pxTopOfStack = portINITIAL_DECNT; /* DECNT. */
 238             pxTopOfStack--;
 239             *pxTopOfStack = portINITIAL_DCMR;  /* DCMR. */
 240             pxTopOfStack--;
 241             *pxTopOfStack = portINITIAL_DPSW;  /* DPSW. */
 242         }
 243     #elif ( configUSE_TASK_DPFPU_SUPPORT == 0 )
 244         {
 245             /* Omit DPFPU support. */
 246         }
 247     #else /* if ( configUSE_TASK_DPFPU_SUPPORT == 1 ) */
 248         {
 249             #error Invalid configUSE_TASK_DPFPU_SUPPORT setting - configUSE_TASK_DPFPU_SUPPORT must be set to 0, 1, 2, or left undefined.
 250         }
 251     #endif /* if ( configUSE_TASK_DPFPU_SUPPORT == 1 ) */
 252
 253     return pxTopOfStack;
 254 }
 255 /*-----------------------------------------------------------*/
 256
 257 #if ( configUSE_TASK_DPFPU_SUPPORT == 1 )
 258
 259     void vPortTaskUsesDPFPU( void )
 260     {
 261         /* A task is registering the fact that it needs a DPFPU context.  Set the
 262          * DPFPU flag (which is saved as part of the task context). */
 263         ulPortTaskHasDPFPUContext = portHAS_DPFPU_CONTEXT;
 264     }
 265
 266 #endif /* configUSE_TASK_DPFPU_SUPPORT */
 267 /*-----------------------------------------------------------*/
 268
 269 BaseType_t xPortStartScheduler( void )
 270 {
 271     extern void vApplicationSetupTimerInterrupt( void );
 272
 273     /* Use pxCurrentTCB just so it does not get optimised away. */
 274     if( pxCurrentTCB != NULL )
 275     {
 276         /* Call an application function to set up the timer that will generate the
 277          * tick interrupt.  This way the application can decide which peripheral to
 278          * use.  A demo application is provided to show a suitable example. */
 279         vApplicationSetupTimerInterrupt();
 280
 281         /* Enable the software interrupt. */
 282         _IEN( _ICU_SWINT ) = 1;
 283
 284         /* Ensure the software interrupt is clear. */
 285         _IR( _ICU_SWINT ) = 0;
 286
 287         /* Ensure the software interrupt is set to the kernel priority. */
 288         _IPR( _ICU_SWINT ) = configKERNEL_INTERRUPT_PRIORITY;
 289
 290         /* Start the first task. */
 291         prvStartFirstTask();
 292     }
 293
 294     /* Should not get here. */
 295     return pdFAIL;
 296 }
 297 /*-----------------------------------------------------------*/
 298
 299 void vPortEndScheduler( void )
 300 {
 301     /* Not implemented in ports where there is nothing to return to.
 302      * Artificially force an assert. */
 303     configASSERT( pxCurrentTCB == NULL );
 304
 305     /* The following line is just to prevent the symbol getting optimised away. */
 306     ( void ) vTaskSwitchContext();
 307 }
 308 /*-----------------------------------------------------------*/
 309
 310 static void prvStartFirstTask( void )
 311 {
 312     __asm volatile
 313     (
 314
 315         /* When starting the scheduler there is nothing that needs moving to the
 316          * interrupt stack because the function is not called from an interrupt.
 317          * Just ensure the current stack is the user stack. */
 318         "SETPSW         U                                               \n"\
 319
 320
 321         /* Obtain the location of the stack associated with which ever task
 322          * pxCurrentTCB is currently pointing to. */
 323         "MOV.L          #_pxCurrentTCB, R15             \n"\
 324         "MOV.L          [R15], R15                              \n"\
 325         "MOV.L          [R15], R0                               \n"\
 326
 327
 328         /* Restore the registers from the stack of the task pointed to by
 329          * pxCurrentTCB. */
 330
 331         #if ( configUSE_TASK_DPFPU_SUPPORT == 1 )
 332
 333             /* The restored ulPortTaskHasDPFPUContext is to be zero here.
 334              * So, it is never necessary to restore the DPFPU context here. */
 335             "POP                R15                                                                     \n"\
 336             "MOV.L              #_ulPortTaskHasDPFPUContext, R14        \n"\
 337             "MOV.L              R15, [R14]                                                      \n"\
 338
 339         #elif ( configUSE_TASK_DPFPU_SUPPORT == 2 )
 340
 341             /* Restore the DPFPU context. */
 342             "DPOPM.L    DPSW-DECNT                              \n"\
 343             "DPOPM.D    DR0-DR15                                \n"\
 344
 345         #endif /* if ( configUSE_TASK_DPFPU_SUPPORT == 1 ) */
 346
 347         "POP            R15                                             \n"\
 348
 349         /* Accumulator low 32 bits. */
 350         "MVTACLO        R15, A0                                 \n"\
 351         "POP            R15                                             \n"\
 352
 353         /* Accumulator high 32 bits. */
 354         "MVTACHI        R15, A0                                 \n"\
 355         "POP            R15                                             \n"\
 356
 357         /* Accumulator guard. */
 358         "MVTACGU        R15, A0                                 \n"\
 359         "POP            R15                                             \n"\
 360
 361         /* Accumulator low 32 bits. */
 362         "MVTACLO        R15, A1                                 \n"\
 363         "POP            R15                                             \n"\
 364
 365         /* Accumulator high 32 bits. */
 366         "MVTACHI        R15, A1                                 \n"\
 367         "POP            R15                                             \n"\
 368
 369         /* Accumulator guard. */
 370         "MVTACGU        R15, A1                                 \n"\
 371         "POP            R15                                             \n"\
 372
 373         /* Floating point status word. */
 374         "MVTC           R15, FPSW                               \n"\
 375
 376         /* R1 to R15 - R0 is not included as it is the SP. */
 377         "POPM           R1-R15                                  \n"\
 378
 379         /* This pops the remaining registers. */
 380         "RTE                                                            \n"\
 381         "NOP                                                            \n"\
 382         "NOP                                                            \n"
 383     );
 384 }
 385 /*-----------------------------------------------------------*/
 386
 387 #pragma vector = VECT( ICU, SWINT )
 388 __interrupt void vSoftwareInterruptISR( void )
 389 {
 390     __asm volatile
 391     (
 392         /* Re-enable interrupts. */
 393         "SETPSW         I                                                       \n"\
 394
 395
 396         /* Move the data that was automatically pushed onto the interrupt stack when
 397          * the interrupt occurred from the interrupt stack to the user stack.
 398          *
 399          * R15 is saved before it is clobbered. */
 400         "PUSH.L         R15                                                     \n"\
 401
 402         /* Read the user stack pointer. */
 403         "MVFC           USP, R15                                        \n"\
 404
 405         /* Move the address down to the data being moved. */
 406         "SUB            #12, R15                                        \n"\
 407         "MVTC           R15, USP                                        \n"\
 408
 409         /* Copy the data across, R15, then PC, then PSW. */
 410         "MOV.L          [ R0 ], [ R15 ]                         \n"\
 411         "MOV.L          4[ R0 ], 4[ R15 ]                       \n"\
 412         "MOV.L          8[ R0 ], 8[ R15 ]                       \n"\
 413
 414         /* Move the interrupt stack pointer to its new correct position. */
 415         "ADD            #12, R0                                         \n"\
 416
 417         /* All the rest of the registers are saved directly to the user stack. */
 418         "SETPSW         U                                                       \n"\
 419
 420         /* Save the rest of the general registers (R15 has been saved already). */
 421         "PUSHM          R1-R14                                          \n"\
 422
 423         /* Save the FPSW and accumulators. */
 424         "MVFC           FPSW, R15                                       \n"\
 425         "PUSH.L         R15                                                     \n"\
 426         "MVFACGU        #0, A1, R15                                     \n"\
 427         "PUSH.L         R15                                                     \n"\
 428         "MVFACHI        #0, A1, R15                                     \n"\
 429         "PUSH.L         R15                                                     \n"\
 430         "MVFACLO        #0, A1, R15                                     \n" /* Low order word. */ \
 431         "PUSH.L         R15                                                     \n"\
 432         "MVFACGU        #0, A0, R15                                     \n"\
 433         "PUSH.L         R15                                                     \n"\
 434         "MVFACHI        #0, A0, R15                                     \n"\
 435         "PUSH.L         R15                                                     \n"\
 436         "MVFACLO        #0, A0, R15                                     \n" /* Low order word. */ \
 437         "PUSH.L         R15                                                     \n"\
 438
 439         #if ( configUSE_TASK_DPFPU_SUPPORT == 1 )
 440
 441             /* Does the task have a DPFPU context that needs saving?  If
 442              * ulPortTaskHasDPFPUContext is 0 then no. */
 443             "MOV.L              #_ulPortTaskHasDPFPUContext, R15        \n"\
 444             "MOV.L              [R15], R15                                                      \n"\
 445             "CMP                #0, R15                                                         \n"\
 446
 447             /* Save the DPFPU context, if any. */
 448             "BEQ.B              __lab1                                          \n"\
 449             "DPUSHM.D   DR0-DR15                                        \n"\
 450             "DPUSHM.L   DPSW-DECNT                                      \n"\
 451             "__lab1:                                                            \n"\
 452
 453             /* Save ulPortTaskHasDPFPUContext itself. */
 454             "PUSH.L             R15                                                     \n"\
 455
 456         #elif ( configUSE_TASK_DPFPU_SUPPORT == 2 )
 457
 458             /* Save the DPFPU context, always. */
 459             "DPUSHM.D   DR0-DR15                                        \n"\
 460             "DPUSHM.L   DPSW-DECNT                                      \n"\
 461
 462         #endif /* if ( configUSE_TASK_DPFPU_SUPPORT == 1 ) */
 463
 464
 465         /* Save the stack pointer to the TCB. */
 466         "MOV.L          #_pxCurrentTCB, R15                     \n"\
 467         "MOV.L          [ R15 ], R15                            \n"\
 468         "MOV.L          R0, [ R15 ]                                     \n"\
 469
 470
 471         /* Ensure the interrupt mask is set to the syscall priority while the kernel
 472          * structures are being accessed. */
 473         "MVTIPL         %0                                                      \n"\
 474
 475         /* Select the next task to run. */
 476         "BSR.A          _vTaskSwitchContext                     \n"\
 477
 478         /* Reset the interrupt mask as no more data structure access is required. */
 479         "MVTIPL         %1                                                      \n"\
 480
 481
 482         /* Load the stack pointer of the task that is now selected as the Running
 483          * state task from its TCB. */
 484         "MOV.L          #_pxCurrentTCB,R15                      \n"\
 485         "MOV.L          [ R15 ], R15                            \n"\
 486         "MOV.L          [ R15 ], R0                                     \n"\
 487
 488
 489         /* Restore the context of the new task.  The PSW (Program Status Word) and
 490          * PC will be popped by the RTE instruction. */
 491
 492         #if ( configUSE_TASK_DPFPU_SUPPORT == 1 )
 493
 494             /* Is there a DPFPU context to restore?  If the restored
 495              * ulPortTaskHasDPFPUContext is zero then no. */
 496             "POP                R15                                                                     \n"\
 497             "MOV.L              #_ulPortTaskHasDPFPUContext, R14        \n"\
 498             "MOV.L              R15, [R14]                                                      \n"\
 499             "CMP                #0, R15                                                         \n"\
 500
 501             /* Restore the DPFPU context, if any. */
 502             "BEQ.B              __lab2                                          \n"\
 503             "DPOPM.L    DPSW-DECNT                                      \n"\
 504             "DPOPM.D    DR0-DR15                                        \n"\
 505             "__lab2:                                                            \n"\
 506
 507         #elif ( configUSE_TASK_DPFPU_SUPPORT == 2 )
 508
 509             /* Restore the DPFPU context, always. */
 510             "DPOPM.L    DPSW-DECNT                                      \n"\
 511             "DPOPM.D    DR0-DR15                                        \n"\
 512
 513         #endif /* if( configUSE_TASK_DPFPU_SUPPORT == 1 ) */
 514
 515         "POP            R15                                                     \n"\
 516
 517         /* Accumulator low 32 bits. */
 518         "MVTACLO        R15, A0                                         \n"\
 519         "POP            R15                                                     \n"\
 520
 521         /* Accumulator high 32 bits. */
 522         "MVTACHI        R15, A0                                         \n"\
 523         "POP            R15                                                     \n"\
 524
 525         /* Accumulator guard. */
 526         "MVTACGU        R15, A0                                         \n"\
 527         "POP            R15                                                     \n"\
 528
 529         /* Accumulator low 32 bits. */
 530         "MVTACLO        R15, A1                                         \n"\
 531         "POP            R15                                                     \n"\
 532
 533         /* Accumulator high 32 bits. */
 534         "MVTACHI        R15, A1                                         \n"\
 535         "POP            R15                                                     \n"\
 536
 537         /* Accumulator guard. */
 538         "MVTACGU        R15, A1                                         \n"\
 539         "POP            R15                                                     \n"\
 540         "MVTC           R15, FPSW                                       \n"\
 541         "POPM           R1-R15                                          \n"\
 542         "RTE                                                                    \n"\
 543         "NOP                                                                    \n"\
 544         "NOP                                                                      "
 545         portCDT_NO_PARSE( :: ) "i" ( configMAX_SYSCALL_INTERRUPT_PRIORITY ), "i" ( configKERNEL_INTERRUPT_PRIORITY )
 546     );
 547 }
 548 /*-----------------------------------------------------------*/
 549
 550 #pragma vector = _VECT( configTICK_VECTOR )
 551 __interrupt void vTickISR( void )
 552 {
 553     /* Re-enable interrupts. */
 554     __enable_interrupt();
 555
 556     /* Increment the tick, and perform any processing the new tick value
 557      * necessitates.  Ensure IPL is at the max syscall value first. */
 558     __set_interrupt_level( configMAX_SYSCALL_INTERRUPT_PRIORITY );
 559     {
 560         if( xTaskIncrementTick() != pdFALSE )
 561         {
 562             taskYIELD();
 563         }
 564     }
 565     __set_interrupt_level( configKERNEL_INTERRUPT_PRIORITY );
 566 }
 567 /*-----------------------------------------------------------*/