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

   1 /*
   2  * FreeRTOS Kernel V10.5.0
   3  * Copyright (C) 2021 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
   4  *
   5  * SPDX-License-Identifier: MIT
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy of
   8  * this software and associated documentation files (the "Software"), to deal in
   9  * the Software without restriction, including without limitation the rights to
  10  * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
  11  * the Software, and to permit persons to whom the Software is furnished to do so,
  12  * subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in all
  15  * copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  19  * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
  20  * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
  21  * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  *
  24  * https://www.FreeRTOS.org
  25  * https://github.com/FreeRTOS
  26  *
  27  */
  28
  29 /*-----------------------------------------------------------
  30 * Implementation of functions defined in portable.h for the RXv3 DPFPU port.
  31 *----------------------------------------------------------*/
  32
  33 #warning Testing for DFPU support in this port is not yet complete
  34
  35 /* Scheduler includes. */
  36 #include "FreeRTOS.h"
  37 #include "task.h"
  38
  39 /* Library includes. */
  40 #include "string.h"
  41
  42 /* Hardware specifics. */
  43 #if ( configINCLUDE_PLATFORM_H_INSTEAD_OF_IODEFINE_H == 1 )
  44
  45     #include "platform.h"
  46
  47 #else /* configINCLUDE_PLATFORM_H_INSTEAD_OF_IODEFINE_H */
  48
  49     #include "iodefine.h"
  50
  51 #endif /* configINCLUDE_PLATFORM_H_INSTEAD_OF_IODEFINE_H */
  52
  53 /*-----------------------------------------------------------*/
  54
  55 /* Tasks should start with interrupts enabled and in Supervisor mode, therefore
  56  * PSW is set with U and I set, and PM and IPL clear. */
  57 #define portINITIAL_PSW     ( ( StackType_t ) 0x00030000 )
  58 #define portINITIAL_FPSW    ( ( StackType_t ) 0x00000100 )
  59 #define portINITIAL_DPSW    ( ( StackType_t ) 0x00000100 )
  60 #define portINITIAL_DCMR    ( ( StackType_t ) 0x00000000 )
  61 #define portINITIAL_DECNT   ( ( StackType_t ) 0x00000001 )
  62
  63 /* Tasks are not created with a DPFPU context, but can be given a DPFPU context
  64  * after they have been created.  A variable is stored as part of the tasks context
  65  * that holds portNO_DPFPU_CONTEXT if the task does not have a DPFPU context, or
  66  * any other value if the task does have a DPFPU context. */
  67 #define portNO_DPFPU_CONTEXT    ( ( StackType_t ) 0 )
  68 #define portHAS_DPFPU_CONTEXT   ( ( StackType_t ) 1 )
  69
  70 /* The space on the stack required to hold the DPFPU data registers.  This is 16
  71  * 64-bit registers. */
  72 #define portDPFPU_DATA_REGISTER_WORDS   ( 16 * 2 )
  73
  74 /*-----------------------------------------------------------*/
  75
  76 /*
  77  * Function to start the first task executing - written in asm code as direct
  78  * access to registers is required.
  79  */
  80 static void prvStartFirstTask( void );
  81
  82 /*
  83  * Software interrupt handler.  Performs the actual context switch (saving and
  84  * restoring of registers).  Written in asm code as direct register access is
  85  * required.
  86  */
  87 __interrupt void vSoftwareInterruptISR( void );
  88
  89 /*
  90  * The tick ISR handler.  The peripheral used is configured by the application
  91  * via a hook/callback function.
  92  */
  93 __interrupt void vTickISR( void );
  94
  95 /*-----------------------------------------------------------*/
  96
  97 /* Saved as part of the task context.  If ulPortTaskHasDPFPUContext is non-zero
  98  * then a DPFPU context must be saved and restored for the task. */
  99 #if ( configUSE_TASK_DPFPU_SUPPORT == 1 )
 100
 101     StackType_t ulPortTaskHasDPFPUContext = portNO_DPFPU_CONTEXT;
 102
 103 #endif /* configUSE_TASK_DPFPU_SUPPORT */
 104
 105 /* This is accessed by the inline assembler functions so is file scope for
 106  * convenience. */
 107 extern void * pxCurrentTCB;
 108 extern void vTaskSwitchContext( void );
 109
 110 /*-----------------------------------------------------------*/
 111
 112 /*
 113  * See header file for description.
 114  */
 115 StackType_t * pxPortInitialiseStack( StackType_t * pxTopOfStack,
 116                                      TaskFunction_t pxCode,
 117                                      void * pvParameters )
 118 {
 119     /* R0 is not included as it is the stack pointer. */
 120
 121     *pxTopOfStack = 0x00;
 122     pxTopOfStack--;
 123     *pxTopOfStack = portINITIAL_PSW;
 124     pxTopOfStack--;
 125     *pxTopOfStack = ( StackType_t ) pxCode;
 126
 127     /* When debugging it can be useful if every register is set to a known
 128      * value.  Otherwise code space can be saved by just setting the registers
 129      * that need to be set. */
 130     #ifdef USE_FULL_REGISTER_INITIALISATION
 131         {
 132             pxTopOfStack--;
 133             *pxTopOfStack = 0xffffffff; /* r15. */
 134             pxTopOfStack--;
 135             *pxTopOfStack = 0xeeeeeeee;
 136             pxTopOfStack--;
 137             *pxTopOfStack = 0xdddddddd;
 138             pxTopOfStack--;
 139             *pxTopOfStack = 0xcccccccc;
 140             pxTopOfStack--;
 141             *pxTopOfStack = 0xbbbbbbbb;
 142             pxTopOfStack--;
 143             *pxTopOfStack = 0xaaaaaaaa;
 144             pxTopOfStack--;
 145             *pxTopOfStack = 0x99999999;
 146             pxTopOfStack--;
 147             *pxTopOfStack = 0x88888888;
 148             pxTopOfStack--;
 149             *pxTopOfStack = 0x77777777;
 150             pxTopOfStack--;
 151             *pxTopOfStack = 0x66666666;
 152             pxTopOfStack--;
 153             *pxTopOfStack = 0x55555555;
 154             pxTopOfStack--;
 155             *pxTopOfStack = 0x44444444;
 156             pxTopOfStack--;
 157             *pxTopOfStack = 0x33333333;
 158             pxTopOfStack--;
 159             *pxTopOfStack = 0x22222222;
 160             pxTopOfStack--;
 161         }
 162     #else /* ifdef USE_FULL_REGISTER_INITIALISATION */
 163         {
 164             pxTopOfStack -= 15;
 165         }
 166     #endif /* ifdef USE_FULL_REGISTER_INITIALISATION */
 167
 168     *pxTopOfStack = ( StackType_t ) pvParameters; /* R1 */
 169     pxTopOfStack--;
 170     *pxTopOfStack = portINITIAL_FPSW;
 171     pxTopOfStack--;
 172     *pxTopOfStack = 0x11111111; /* Accumulator 1. */
 173     pxTopOfStack--;
 174     *pxTopOfStack = 0x22222222; /* Accumulator 1. */
 175     pxTopOfStack--;
 176     *pxTopOfStack = 0x33333333; /* Accumulator 1. */
 177     pxTopOfStack--;
 178     *pxTopOfStack = 0x44444444; /* Accumulator 0. */
 179     pxTopOfStack--;
 180     *pxTopOfStack = 0x55555555; /* Accumulator 0. */
 181     pxTopOfStack--;
 182     *pxTopOfStack = 0x66666666; /* Accumulator 0. */
 183
 184     #if ( configUSE_TASK_DPFPU_SUPPORT == 1 )
 185         {
 186             /* The task will start without a DPFPU context.  A task that
 187              * uses the DPFPU hardware must call vPortTaskUsesDPFPU() before
 188              * executing any floating point instructions. */
 189             pxTopOfStack--;
 190             *pxTopOfStack = portNO_DPFPU_CONTEXT;
 191         }
 192     #elif ( configUSE_TASK_DPFPU_SUPPORT == 2 )
 193         {
 194             /* The task will start with a DPFPU context.  Leave enough
 195              * space for the registers - and ensure they are initialised if desired. */
 196             #ifdef USE_FULL_REGISTER_INITIALISATION
 197                 {
 198                     pxTopOfStack -= 2;
 199                     *(double *)pxTopOfStack = 1515.1515; /* DR15. */
 200                     pxTopOfStack -= 2;
 201                     *(double *)pxTopOfStack = 1414.1414; /* DR14. */
 202                     pxTopOfStack -= 2;
 203                     *(double *)pxTopOfStack = 1313.1313; /* DR13. */
 204                     pxTopOfStack -= 2;
 205                     *(double *)pxTopOfStack = 1212.1212; /* DR12. */
 206                     pxTopOfStack -= 2;
 207                     *(double *)pxTopOfStack = 1111.1111; /* DR11. */
 208                     pxTopOfStack -= 2;
 209                     *(double *)pxTopOfStack = 1010.1010; /* DR10. */
 210                     pxTopOfStack -= 2;
 211                     *(double *)pxTopOfStack =  909.0909; /* DR9. */
 212                     pxTopOfStack -= 2;
 213                     *(double *)pxTopOfStack =  808.0808; /* DR8. */
 214                     pxTopOfStack -= 2;
 215                     *(double *)pxTopOfStack =  707.0707; /* DR7. */
 216                     pxTopOfStack -= 2;
 217                     *(double *)pxTopOfStack =  606.0606; /* DR6. */
 218                     pxTopOfStack -= 2;
 219                     *(double *)pxTopOfStack =  505.0505; /* DR5. */
 220                     pxTopOfStack -= 2;
 221                     *(double *)pxTopOfStack =  404.0404; /* DR4. */
 222                     pxTopOfStack -= 2;
 223                     *(double *)pxTopOfStack =  303.0303; /* DR3. */
 224                     pxTopOfStack -= 2;
 225                     *(double *)pxTopOfStack =  202.0202; /* DR2. */
 226                     pxTopOfStack -= 2;
 227                     *(double *)pxTopOfStack =  101.0101; /* DR1. */
 228                     pxTopOfStack -= 2;
 229                     *(double *)pxTopOfStack = 9876.54321;/* DR0. */
 230                 }
 231             #else /* ifdef USE_FULL_REGISTER_INITIALISATION */
 232                 {
 233                     pxTopOfStack -= portDPFPU_DATA_REGISTER_WORDS;
 234                     memset( pxTopOfStack, 0x00, portDPFPU_DATA_REGISTER_WORDS * sizeof( StackType_t ) );
 235                 }
 236             #endif /* ifdef USE_FULL_REGISTER_INITIALISATION */
 237             pxTopOfStack--;
 238             *pxTopOfStack = portINITIAL_DECNT; /* DECNT. */
 239             pxTopOfStack--;
 240             *pxTopOfStack = portINITIAL_DCMR;  /* DCMR. */
 241             pxTopOfStack--;
 242             *pxTopOfStack = portINITIAL_DPSW;  /* DPSW. */
 243         }
 244     #elif ( configUSE_TASK_DPFPU_SUPPORT == 0 )
 245         {
 246             /* Omit DPFPU support. */
 247         }
 248     #else /* if ( configUSE_TASK_DPFPU_SUPPORT == 1 ) */
 249         {
 250             #error Invalid configUSE_TASK_DPFPU_SUPPORT setting - configUSE_TASK_DPFPU_SUPPORT must be set to 0, 1, 2, or left undefined.
 251         }
 252     #endif /* if ( configUSE_TASK_DPFPU_SUPPORT == 1 ) */
 253
 254     return pxTopOfStack;
 255 }
 256 /*-----------------------------------------------------------*/
 257
 258 #if ( configUSE_TASK_DPFPU_SUPPORT == 1 )
 259
 260     void vPortTaskUsesDPFPU( void )
 261     {
 262         /* A task is registering the fact that it needs a DPFPU context.  Set the
 263          * DPFPU flag (which is saved as part of the task context). */
 264         ulPortTaskHasDPFPUContext = portHAS_DPFPU_CONTEXT;
 265     }
 266
 267 #endif /* configUSE_TASK_DPFPU_SUPPORT */
 268 /*-----------------------------------------------------------*/
 269
 270 BaseType_t xPortStartScheduler( void )
 271 {
 272     extern void vApplicationSetupTimerInterrupt( void );
 273
 274     /* Use pxCurrentTCB just so it does not get optimised away. */
 275     if( pxCurrentTCB != NULL )
 276     {
 277         /* Call an application function to set up the timer that will generate the
 278          * tick interrupt.  This way the application can decide which peripheral to
 279          * use.  A demo application is provided to show a suitable example. */
 280         vApplicationSetupTimerInterrupt();
 281
 282         /* Enable the software interrupt. */
 283         _IEN( _ICU_SWINT ) = 1;
 284
 285         /* Ensure the software interrupt is clear. */
 286         _IR( _ICU_SWINT ) = 0;
 287
 288         /* Ensure the software interrupt is set to the kernel priority. */
 289         _IPR( _ICU_SWINT ) = configKERNEL_INTERRUPT_PRIORITY;
 290
 291         /* Start the first task. */
 292         prvStartFirstTask();
 293     }
 294
 295     /* Should not get here. */
 296     return pdFAIL;
 297 }
 298 /*-----------------------------------------------------------*/
 299
 300 void vPortEndScheduler( void )
 301 {
 302     /* Not implemented in ports where there is nothing to return to.
 303      * Artificially force an assert. */
 304     configASSERT( pxCurrentTCB == NULL );
 305
 306     /* The following line is just to prevent the symbol getting optimised away. */
 307     ( void ) vTaskSwitchContext();
 308 }
 309 /*-----------------------------------------------------------*/
 310
 311 static void prvStartFirstTask( void )
 312 {
 313     __asm volatile
 314     (
 315
 316         /* When starting the scheduler there is nothing that needs moving to the
 317          * interrupt stack because the function is not called from an interrupt.
 318          * Just ensure the current stack is the user stack. */
 319         "SETPSW         U                                               \n"\
 320
 321
 322         /* Obtain the location of the stack associated with which ever task
 323          * pxCurrentTCB is currently pointing to. */
 324         "MOV.L          #_pxCurrentTCB, R15             \n"\
 325         "MOV.L          [R15], R15                              \n"\
 326         "MOV.L          [R15], R0                               \n"\
 327
 328
 329         /* Restore the registers from the stack of the task pointed to by
 330          * pxCurrentTCB. */
 331
 332         #if ( configUSE_TASK_DPFPU_SUPPORT == 1 )
 333
 334             /* The restored ulPortTaskHasDPFPUContext is to be zero here.
 335              * So, it is never necessary to restore the DPFPU context here. */
 336             "POP                R15                                                                     \n"\
 337             "MOV.L              #_ulPortTaskHasDPFPUContext, R14        \n"\
 338             "MOV.L              R15, [R14]                                                      \n"\
 339
 340         #elif ( configUSE_TASK_DPFPU_SUPPORT == 2 )
 341
 342             /* Restore the DPFPU context. */
 343             "DPOPM.L    DPSW-DECNT                              \n"\
 344             "DPOPM.D    DR0-DR15                                \n"\
 345
 346         #endif /* if ( configUSE_TASK_DPFPU_SUPPORT == 1 ) */
 347
 348         "POP            R15                                             \n"\
 349
 350         /* Accumulator low 32 bits. */
 351         "MVTACLO        R15, A0                                 \n"\
 352         "POP            R15                                             \n"\
 353
 354         /* Accumulator high 32 bits. */
 355         "MVTACHI        R15, A0                                 \n"\
 356         "POP            R15                                             \n"\
 357
 358         /* Accumulator guard. */
 359         "MVTACGU        R15, A0                                 \n"\
 360         "POP            R15                                             \n"\
 361
 362         /* Accumulator low 32 bits. */
 363         "MVTACLO        R15, A1                                 \n"\
 364         "POP            R15                                             \n"\
 365
 366         /* Accumulator high 32 bits. */
 367         "MVTACHI        R15, A1                                 \n"\
 368         "POP            R15                                             \n"\
 369
 370         /* Accumulator guard. */
 371         "MVTACGU        R15, A1                                 \n"\
 372         "POP            R15                                             \n"\
 373
 374         /* Floating point status word. */
 375         "MVTC           R15, FPSW                               \n"\
 376
 377         /* R1 to R15 - R0 is not included as it is the SP. */
 378         "POPM           R1-R15                                  \n"\
 379
 380         /* This pops the remaining registers. */
 381         "RTE                                                            \n"\
 382         "NOP                                                            \n"\
 383         "NOP                                                            \n"
 384     );
 385 }
 386 /*-----------------------------------------------------------*/
 387
 388 #pragma vector = VECT( ICU, SWINT )
 389 __interrupt void vSoftwareInterruptISR( void )
 390 {
 391     __asm volatile
 392     (
 393         /* Re-enable interrupts. */
 394         "SETPSW         I                                                       \n"\
 395
 396
 397         /* Move the data that was automatically pushed onto the interrupt stack when
 398          * the interrupt occurred from the interrupt stack to the user stack.
 399          *
 400          * R15 is saved before it is clobbered. */
 401         "PUSH.L         R15                                                     \n"\
 402
 403         /* Read the user stack pointer. */
 404         "MVFC           USP, R15                                        \n"\
 405
 406         /* Move the address down to the data being moved. */
 407         "SUB            #12, R15                                        \n"\
 408         "MVTC           R15, USP                                        \n"\
 409
 410         /* Copy the data across, R15, then PC, then PSW. */
 411         "MOV.L          [ R0 ], [ R15 ]                         \n"\
 412         "MOV.L          4[ R0 ], 4[ R15 ]                       \n"\
 413         "MOV.L          8[ R0 ], 8[ R15 ]                       \n"\
 414
 415         /* Move the interrupt stack pointer to its new correct position. */
 416         "ADD            #12, R0                                         \n"\
 417
 418         /* All the rest of the registers are saved directly to the user stack. */
 419         "SETPSW         U                                                       \n"\
 420
 421         /* Save the rest of the general registers (R15 has been saved already). */
 422         "PUSHM          R1-R14                                          \n"\
 423
 424         /* Save the FPSW and accumulators. */
 425         "MVFC           FPSW, R15                                       \n"\
 426         "PUSH.L         R15                                                     \n"\
 427         "MVFACGU        #0, A1, R15                                     \n"\
 428         "PUSH.L         R15                                                     \n"\
 429         "MVFACHI        #0, A1, R15                                     \n"\
 430         "PUSH.L         R15                                                     \n"\
 431         "MVFACLO        #0, A1, R15                                     \n" /* Low order word. */ \
 432         "PUSH.L         R15                                                     \n"\
 433         "MVFACGU        #0, A0, R15                                     \n"\
 434         "PUSH.L         R15                                                     \n"\
 435         "MVFACHI        #0, A0, R15                                     \n"\
 436         "PUSH.L         R15                                                     \n"\
 437         "MVFACLO        #0, A0, R15                                     \n" /* Low order word. */ \
 438         "PUSH.L         R15                                                     \n"\
 439
 440         #if ( configUSE_TASK_DPFPU_SUPPORT == 1 )
 441
 442             /* Does the task have a DPFPU context that needs saving?  If
 443              * ulPortTaskHasDPFPUContext is 0 then no. */
 444             "MOV.L              #_ulPortTaskHasDPFPUContext, R15        \n"\
 445             "MOV.L              [R15], R15                                                      \n"\
 446             "CMP                #0, R15                                                         \n"\
 447
 448             /* Save the DPFPU context, if any. */
 449             "BEQ.B              __lab1                                          \n"\
 450             "DPUSHM.D   DR0-DR15                                        \n"\
 451             "DPUSHM.L   DPSW-DECNT                                      \n"\
 452             "__lab1:                                                            \n"\
 453
 454             /* Save ulPortTaskHasDPFPUContext itself. */
 455             "PUSH.L             R15                                                     \n"\
 456
 457         #elif ( configUSE_TASK_DPFPU_SUPPORT == 2 )
 458
 459             /* Save the DPFPU context, always. */
 460             "DPUSHM.D   DR0-DR15                                        \n"\
 461             "DPUSHM.L   DPSW-DECNT                                      \n"\
 462
 463         #endif /* if ( configUSE_TASK_DPFPU_SUPPORT == 1 ) */
 464
 465
 466         /* Save the stack pointer to the TCB. */
 467         "MOV.L          #_pxCurrentTCB, R15                     \n"\
 468         "MOV.L          [ R15 ], R15                            \n"\
 469         "MOV.L          R0, [ R15 ]                                     \n"\
 470
 471
 472         /* Ensure the interrupt mask is set to the syscall priority while the kernel
 473          * structures are being accessed. */
 474         "MVTIPL         %0                                                      \n"\
 475
 476         /* Select the next task to run. */
 477         "BSR.A          _vTaskSwitchContext                     \n"\
 478
 479         /* Reset the interrupt mask as no more data structure access is required. */
 480         "MVTIPL         %1                                                      \n"\
 481
 482
 483         /* Load the stack pointer of the task that is now selected as the Running
 484          * state task from its TCB. */
 485         "MOV.L          #_pxCurrentTCB,R15                      \n"\
 486         "MOV.L          [ R15 ], R15                            \n"\
 487         "MOV.L          [ R15 ], R0                                     \n"\
 488
 489
 490         /* Restore the context of the new task.  The PSW (Program Status Word) and
 491          * PC will be popped by the RTE instruction. */
 492
 493         #if ( configUSE_TASK_DPFPU_SUPPORT == 1 )
 494
 495             /* Is there a DPFPU context to restore?  If the restored
 496              * ulPortTaskHasDPFPUContext is zero then no. */
 497             "POP                R15                                                                     \n"\
 498             "MOV.L              #_ulPortTaskHasDPFPUContext, R14        \n"\
 499             "MOV.L              R15, [R14]                                                      \n"\
 500             "CMP                #0, R15                                                         \n"\
 501
 502             /* Restore the DPFPU context, if any. */
 503             "BEQ.B              __lab2                                          \n"\
 504             "DPOPM.L    DPSW-DECNT                                      \n"\
 505             "DPOPM.D    DR0-DR15                                        \n"\
 506             "__lab2:                                                            \n"\
 507
 508         #elif ( configUSE_TASK_DPFPU_SUPPORT == 2 )
 509
 510             /* Restore the DPFPU context, always. */
 511             "DPOPM.L    DPSW-DECNT                                      \n"\
 512             "DPOPM.D    DR0-DR15                                        \n"\
 513
 514         #endif /* if( configUSE_TASK_DPFPU_SUPPORT == 1 ) */
 515
 516         "POP            R15                                                     \n"\
 517
 518         /* Accumulator low 32 bits. */
 519         "MVTACLO        R15, A0                                         \n"\
 520         "POP            R15                                                     \n"\
 521
 522         /* Accumulator high 32 bits. */
 523         "MVTACHI        R15, A0                                         \n"\
 524         "POP            R15                                                     \n"\
 525
 526         /* Accumulator guard. */
 527         "MVTACGU        R15, A0                                         \n"\
 528         "POP            R15                                                     \n"\
 529
 530         /* Accumulator low 32 bits. */
 531         "MVTACLO        R15, A1                                         \n"\
 532         "POP            R15                                                     \n"\
 533
 534         /* Accumulator high 32 bits. */
 535         "MVTACHI        R15, A1                                         \n"\
 536         "POP            R15                                                     \n"\
 537
 538         /* Accumulator guard. */
 539         "MVTACGU        R15, A1                                         \n"\
 540         "POP            R15                                                     \n"\
 541         "MVTC           R15, FPSW                                       \n"\
 542         "POPM           R1-R15                                          \n"\
 543         "RTE                                                                    \n"\
 544         "NOP                                                                    \n"\
 545         "NOP                                                                      "
 546         portCDT_NO_PARSE( :: ) "i" ( configMAX_SYSCALL_INTERRUPT_PRIORITY ), "i" ( configKERNEL_INTERRUPT_PRIORITY )
 547     );
 548 }
 549 /*-----------------------------------------------------------*/
 550
 551 #pragma vector = _VECT( configTICK_VECTOR )
 552 __interrupt void vTickISR( void )
 553 {
 554     /* Re-enable interrupts. */
 555     __enable_interrupt();
 556
 557     /* Increment the tick, and perform any processing the new tick value
 558      * necessitates.  Ensure IPL is at the max syscall value first. */
 559     __set_interrupt_level( configMAX_SYSCALL_INTERRUPT_PRIORITY );
 560     {
 561         if( xTaskIncrementTick() != pdFALSE )
 562         {
 563             taskYIELD();
 564         }
 565     }
 566     __set_interrupt_level( configKERNEL_INTERRUPT_PRIORITY );
 567 }
 568 /*-----------------------------------------------------------*/