\u4ea7\u751f\u8c03\u5ea6\u7684\u65b9\u6cd5
FreeRTSO\u7684\u4efb\u52a1\u8c03\u5ea6\u53ea\u505a\u4e00\u4ef6\u4e8b\uff0c\u5c31\u662f\u5728\u7cfb\u7edf\u88ab\u8981\u6c42\u4efb\u52a1\u5207\u6362\u65f6\u627e\u5230\u5728\u5c31\u7eea\u8868\u4e2d\u4f18\u5148\u7ea7\u6700\u9ad8\u7684\u4efb\u52a1\u5e76\u5c06CPU\u6267\u884c\u6743\u5207\u7ed9\u5b83\u3002
\u6709\u4e24\u79cd\u65b9\u6cd5\u89e6\u53d1\u4efb\u52a1\u5207\u6362\uff1a\u6267\u884c\u7cfb\u7edf\u547c\u53ebtaskYIELD(),\u4ee5\u53ca\u7cfb\u7edf\u65f6\u949f\u8282\u62cd\u3002
1.\u6267\u884c\u7cfb\u7edf\u547c\u53eb<\/p>\n\n\n\n
{
portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
__DSB();
__ISB();
}<\/p>\n\n\n\n
\u4ee5\u4e0a\u5b8f\u5b9a\u4e49\u4e00\u770b\u5c31\u5f88\u6e05\u6670\u4e86\uff0c\u901a\u8fc7\u5199PendSV\u624b\u52a8\u89e6\u53d1\u7cfb\u7edf\u8c03\u7528\u8fdb\u5165PendSV\u4e2d\u65ad<\/p>\n\n\n\n
2.\u7cfb\u7edf\u65f6\u949f\u8282\u62cd
void SysTick_Handler(void)
{
portDISABLE_INTERRUPTS();
{
if(xTaskIncrementTick != pdFALSE)
{
portNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;
}
}
portENABLE_INTERRUPTS();
}<\/p>\n\n\n\n
\u542f\u52a8\u8c03\u5ea6\uff1a
\u5f53\u4efb\u52a1\u521b\u5efa\u597d\u4e4b\u540e\uff0c\u8c03\u5ea6\u5668\u4e0d\u4f1a\u81ea\u5df1\u5de5\u4f5c\uff0c\u9700\u8981\u8c03\u7528\u7cfb\u7edf\u63a5\u53e3\uff08Task\u7ea7\uff09\u3002\u5728\u5176\u4e2d\u4f1a\u521b\u5efa\u4e00\u4e2a\u7a7a\u95f2\u4efb\u52a1\uff0c\u4e3b\u8981\u5de5\u4f5c\u662f\u56de\u6536\u8d44\u6e90\u3002
1.\u5f53\u521b\u5efa\u597d\u4efb\u52a1\u540e\uff0c\u7a0b\u5e8f\u8c03\u7528\u542f\u52a8\u8c03\u5ea6\u63a5\u53e3\uff1avTaskStartScheduler();
\u521b\u5efa\u7a7a\u95f2\u4efb\u52a1\uff1axTaskCreate(prvIdleTask, “IDLE”, configMINIMAL_STACK_SIZE, (void *)NULL, (tskIDLE_PRIORITY | portPRIVILEGE_BIT), &xIdleTaskHandle);
\u5982\u5f00\u542f\u8f6f\u5b9a\u65f6\u5668\u529f\u80fd\uff0c\u5219\u521b\u5efa\u4e00\u4e2a\u5b9a\u65f6\u5668\u4efb\u52a1\uff1axTimerCreateTimerTask();
\u8fdb\u5165\u4e34\u754c\u5173\u4e2d\u65ad
\u8bbe\u7f6e\u8c03\u5ea6\u5668\u8fd0\u884c\uff1axSchedulerRunning = pdTRUE;
\u8bbe\u7f6eTick\u8ba1\u6570\u5668\u521d\u503c\uff1axTickCount = 0\uff1b
\u8c03\u7528\u542f\u52a8\u8c03\u5ea6\u63a5\u53e3\uff08Port\u7ea7\uff09\uff1axPortStartScheduler()\uff0c\u8ddfCPU\u67b6\u6784\u6709\u5173
\u914d\u7f6ePendSV\u548cSYSTICK\u7684\u4e2d\u65ad\u4f18\u5148\u7ea7
\u914d\u7f6e\u548c\u4f7f\u80fdSystick
\u8bbe\u7f6e\u4e34\u754c\u5d4c\u5957\u521d\u503c\uff1auxCriticalNesting = 0;
\u542f\u52a8\u7b2c\u4e00\u4e2a\u4efb\u52a1\uff1a
\u83b7\u53d6\u4e2d\u65ad\u5411\u91cf\u8868\u5730\u5740
LDR R0, =0xE000ED08
\u53d6\u51fa\u5411\u91cf\u8868\u7b2c\u4e00\u4e2aword\u7a7a\u95f4\u7684\u503c\uff0c\u662f\u4e3b\u5806\u6808\u5730\u5740
LDR R0, [R0]
LDR R0, [R0]
\u8bbe\u7f6eCPU\u7684\u4e3b\u5806\u6808\u5730\u5740\uff1a
MSR MSP, R0
\u4f7f\u80fd\u5916\u90e8\u4e2d\u65ad\u548cFault\u4e2d\u65ad
CPSIE i
CPSIE f
dsb
isb
\u7cfb\u7edf\u547c\u53eb0\uff0c\u8fdb\u5165SVC_Handler
SVC 0<\/p>\n\n\n\n
2.\u8fdb\u5165SVC_Handler
\u83b7\u53d6\u5f53\u524d\u8fd0\u884c\u4efb\u52a1\u7684TCB\uff0c\u5728\u4efb\u52a1\u521b\u5efa\u65f6\uff0c\u5df2\u7ecf\u5c06\u6700\u9ad8\u4f18\u5148\u7ea7\u7684\u4efb\u52a1\u7684TCB\u653e\u8fdb\u4e86pxCurrentTCB\u4e2d
LDR R3, =pxCurrentTCB
LDR R1, [R3]
LDR R0, [R1]
\u6b64\u65f6R0\u4e2d\u5df2\u7ecf\u662fpxCurrentTCB\u7684\u7b2c\u4e00\u4e2a\u6210\u5458\u7684\u5730\u5740\uff0c\u4e5f\u5c31\u662f\u8be5\u4efb\u52a1\u7684\u5806\u6808\u5730\u5740
\u4efb\u52a1\u51fa\u6808
LDMIA R0!, {R4-R11}
\u8bbe\u7f6e\u7ebf\u7a0b\u5806\u6808
MSR PSP, R0
isb
\u6253\u5f00\u4e2d\u65ad
mov R0, #0
MSR BASEPRI, R0
\u9000\u51fa\u5f02\u5e38\u524d\u7684\u8bbe\u7f6e
ORR R14, R14, #1101b
bit3\uff1a\u9000\u51fa\u540e\u4f7f\u7528\u7ebf\u7a0b\u5806\u6808PSP
bit2\uff1a\u9000\u51fa\u540e\u4ece\u7ebf\u7a0b\u5806\u6808\u51fa\u6808
bit0\uff1a\u63a8\u51fa\u540e\u8fd4\u56dethumb\u72b6\u6001\uff0cCM3\u53ea\u6709Thumb\u72b6\u6001\uff0c\u6240\u4ee5\u5fc5\u987b\u4e3a1
\u9000\u51fa\u5f02\u5e38\uff0c\u8df3\u5230R14
\u786c\u4ef6\u81ea\u52a8\u4ecePSP\u4e2dPOP\u72b6\u6001\uff0c\u4e5f\u5c31\u8df3\u53bb\u6267\u884cpxCurrentTCB\u7684\u4efb\u52a1\u4e86\u3002<\/p>\n\n\n\n
3.\u5f53SysTick\u542f\u52a8\u540e\uff0c\u4ea7\u751fSysTick\u4e2d\u65ad
\u5c06RTOS \u7cfb\u7edfTick\u52a01\uff1axTaskIncrementTick
\u8c03\u5ea6\u5668\u672a\u6302\u8d77
xTickCount\u52a01\uff0c
\u5982xTickCount\u7b49\u4e8e0\uff0c\u5219\u5207\u6362\u5ef6\u65f6\u4efb\u52a1\u8868\uff1ataskSWITCH_DELAYED_LISTS()
\u5982xTickCount\u5927\u4e8e\u4e0b\u4e00\u4efb\u52a1\u9501\u5b9a\u65f6\u95f4\uff0c
\u68c0\u67e5\u5ef6\u65f6\u8868\u4e2d\u662f\u5426\u4e3a\u7a7a\uff0c\u7a7a\u5219\u8df3\u8fc7
\u975e\u7a7a\u5ef6\u65f6\u8868\u5219\u53d6\u51fa\u8981\u89e3\u9501\u4efb\u52a1\u7684TCB,\u5e76\u4ece\u72b6\u6001\u94fe\u8868\u4e2d\u79fb\u9664
\u5c06\u8be5\u4efb\u52a1\u6dfb\u52a0\u5230\u7ee7\u7eed\u8868\u4e2d
\u5982\u9700\u4ea7\u751f\u8c03\u5ea6\u5219\u8fd4\u56depdTRUE
\u8c03\u5ea6\u5668\u5df2\u6302\u8d77
\u5c06\u8bb0\u5f55Pending\u7684Tick\u8ba1\u6570\u52a01\uff1b
\u5982xTaskIncrementTick\u8fd4\u56depdTRUE\uff0c\u8868\u660e\u5f53\u524d\u9700\u8981\u4ea7\u751f\u4e00\u6b21\u8c03\u5ea6\uff0c\u4e8e\u662f\u624b\u52a8\u89e6\u53d1PendSV\u8fdb\u5982PendSV\u4e2d\u65ad
\u624b\u52a8\u89e6\u53d1PendSV\uff1aportNVIC_INT_CTRL_REG = portNVIC_PENDSVSET_BIT;<\/p>\n\n\n\n
4.PendSV\u4e2d\u65ad\u5904\u7406
\u5f53\u89e6\u53d1PendSV\u4e4b\u540e\uff0cCortexM3\u786c\u4ef6\u81ea\u52a8\u538b\u6808[R0 – R3, R12, LR, PSR, PC]\uff0c\u5c06\u8fdb\u5f02\u5e38\u4e4b\u524d\u7684CPU\u72b6\u6001
\u4fdd\u5b58\u5230\u7ebf\u7a0b\u5806\u6808PSP\u4e2d\uff0c\u5047\u5982\u8dd1\u4efb\u52a1A\u65f6\u8fdb\u7684\u5f02\u5e38\uff0c\u5219\u5c06CPU\u72b6\u6001\u538b\u5230\u4efb\u52a1A\u7684\u5806\u6808\u4e2d\uff0c\u7136\u540e\u8fdb\u5165\u4e2d\u65ad\uff0c
\u6b64\u65f6CPU\u5de5\u4f5c\u5728\u7279\u6743\u6a21\u5f0f\u4e0b\uff0c\u4f7f\u7528\u7684\u65f6\u4e3b\u5806\u6808MSP\u3002<\/p>\n\n\n\n
\u5f53\u8fdb\u5165\u4e2d\u65ad\u540e\uff0c\u9996\u5148\u4fdd\u5b58\u4efb\u52a1A\u7684\u73b0\u573a\uff0c\u786c\u4ef6\u5df2\u7ecf\u538b\u4e868\u4e2a\u5bc4\u5b58\u5668\uff0c\u5269\u4e0b\u7684[R4 - R11]\u9700\u8981\u624b\u52a8\u538b\u6808\n\n1.\u9996\u5148\u83b7\u53d6\u5f53\u524d\u8fd0\u884c\u4efb\u52a1\uff08\u5207\u6362\u524d\uff09\u7684TCB,\u548c\u5f53\u524d\u7684\u7ebf\u7a0b\u6808\n MRS R0, PSP\n isb\n LDR R3\uff0c=pxCurrentTCB\n LDR R2, [r3]\n2.\u624b\u52a8\u538b\u6808\uff0c\u5df2\u77e5\u786c\u4ef6\u81ea\u52a8\u538b\u4e868\u4e2a\uff0c\u5269\u4e0b\u7684\u624b\u52a8\u538b\u6808\n stmdb R0!, {R4 - R11} ;R0\u4e2d\u4e3a\u65e7\u4efb\u52a1\u7684\u7ebf\u7a0b\u5806\u6808\uff0c\u786c\u4ef6\u538b\u6808\u4e5f\u5728\u91cc\u9762\uff0c\u624b\u52a8\u538b\u7684\u4e5f\u538b\u5728\u91cc\u9762\n str R0, [R2] ;R2\u4e2d\u4e3a\u65e7\u4efb\u52a1\u7684TCB\u6307\u9488\uff0c\u4e5f\u662f\u4efb\u52a1\u7684\u5806\u6808\u6808\u9876\u6307\u9488\uff0cR0\u4e3a\u538b\u6808\u540e\u7684\u6808\u9876\u6307\u9488\u503c\uff0c\u66f4\u65b0\u5230R2\u4e2d\n3.\u4fdd\u5b58\u73b0\u573a\u51c6\u5907\u8df3\u8f6c\uff0c\u5c06R3\u548cR14\u7684\u503c\u538b\u6808\uff0c\u8fd9\u91cc\u662f\u5728\u5f02\u5e38\u4e2d\u7528\u7684\u662f\u4e3b\u5806\u6808\n stmdb sp!, {R3, R14}\n4.\u5c4f\u853d\u4e2d\u65ad\n mov R0, #configMAX_SYSCALL_INTERRUPT_PRIORITY\n msr basepri, r0\n dsb\n isb\n5.\u6267\u884c\u4e0a\u4e0b\u6587\u5207\u6362\n bl vTaskSwitchContext\n6.\u6253\u5f00\u4e2d\u65ad\n mov R0, #0\n msr basepri, R0\n7.\u6309\u524d\u9762\u7684\u538b\u6808\u987a\u5e8f\u51fa\u6808\n ldmia sp!, {R3, R14}\n8.\u65b0\u4efb\u52a1\u51fa\u6808\n ldr R1, [R3] ;R3\u4e2d\u662f\u6b63\u5728\u8fd0\u884c\u4efb\u52a1\u7684TCB\u5730\u5740\uff0c\u5b9e\u9645\u4e0a\u8fd9\u4e2a\u5730\u5740\u5728\u7b2c5\u6b65\u4e2d\u5df2\u7ecf\u66ff\u6362\u6210\u65b0\u4efb\u52a1\u7684TCB\u4e86\uff0c\n ldr R0, [R1] ;\u53d6\u51fa\u65b0TCB\u7684\u5730\u5740\u4e2d\u7684\u503c\uff0c\u4e5f\u5c31\u662f\u65b0\u4efb\u52a1\u7684\u6808\u9876\u5730\u5740\n ldmia R0!, {R4 - R11} ;\u53ea\u9700\u8981\u51fa\u6808\u624b\u52a8\u538b\u6808\u76848\u4e2a\uff0c\u786c\u4ef6\u538b\u6808\u7684\u786c\u4ef6\u81ea\u5df1\u4f1a\u51fa\u6808\uff1b\n msr PSP, R0 ;\u5c06\u51fa\u6808\u540e\u7684\u6808\u9876\u6307\u9488\u8bbe\u7f6e\u5230CPU\u7684PSP\u5bc4\u5b58\u5668\n isb\n9.\u4e2d\u65ad\u6267\u884c\u5b8c\u6210\uff0c\u5373\u5c06\u9000\u51fa\u5f02\u5e38\uff0c\u8fd9\u4e2a\u65f6\u5019PSP\u5df2\u7ecf\u662f\u65b0\u4efb\u52a1\u7684\u5806\u6808\u5730\u5740\u4e86\uff0c\u90a3\u4e48\u786c\u4ef6\u51fa\u6808\u4e5f\u4f1a\u4ece\u91cc\u9762POP\n bx R14\n10.vTaskSwitchContext\u4efb\u52a1TCB\u7684\u66ff\u6362\n \u83b7\u53d6\u5c31\u7eea\u8868\u4e2d\u6700\u9ad8\u7684\u4f18\u5148\u7ea7:\n portGET_HIGHEST_PRIORITY(uxTopPriority, uxTopReadyPriority)\n uxTopPriority = (31 - __clz(uxTopReadyPriority)); \u8ba1\u7b97\u524d\u5bfc0\uff0c__clz,\u4ece0\u5f00\u59cb\u7684\u7b2c\u51e0\u4e2abit\u4e3a0\uff0c\u6bd4\u5982\u7b2c\u4e00\u4e2a0\u662f\u5728bit16\uff0c\u5219\u8fd0\u7b97\u7ed3\u679c\u4e3a16\n pxCurrentTCB, &pxReadyTaskLists[uxTopPriority],\u83b7\u53d6\u5c31\u7eea\u8868\u4e2d\u4f18\u5148\u7ea7\u6700\u9ad8\u7684TCB\uff0c\u6302\u5230pxCurrentTCB\n \u6839\u636e\u4efb\u52a1\u4f18\u5148\u7ea7\u627e\u5230\u8be5\u4efb\u52a1\u7684TCB\uff0c\u5e76\u5c06\u5176\u5b58\u653e\u5230 pxCurrentTCB \u4e2d\n \u9000\u51fa\uff0c\u5c31\u8fd9\u6837\u5b9e\u73b0pxCurrentTCB\u5185\u5bb9\u7684\u5207\u6362\n11.\u5c0f\u7ed3\uff1a\u4efb\u52a1\u5207\u6362\u8ddf\u51fd\u6570\u5207\u6362\u6709\u5dee\u5f02\uff0c\u51fd\u6570\u8df3\u8f6c\u66f4\u591a\u7684\u5173\u6ce8\u662f\u88ab\u786c\u4ef6\u538b\u6808\u7684\u72b6\u6001\uff0c\u4f46\u662f\u4efb\u52a1\u5207\u6362\u65f6\u5b8c\u6574\u7684\nCPu\u72b6\u6001\u66ff\u6362\uff0c\u6240\u4ee5\u51fa\u4e86\u786c\u4ef6\u538b\u6808\uff0c\u8fd8\u5f97\u8f6f\u4ef6\u538b\u6808\uff0c\u6062\u590d\u4efb\u52a1\u73b0\u573a\u65f6\u4e5f\u9700\u8981\u8f6f\u4ef6\u51fa\u6808\u3002<\/code><\/pre>\n\n\n\n<\/p>\n","protected":false},"excerpt":{"rendered":"
\u4ea7\u751f\u8c03\u5ea6\u7684\u65b9\u6cd5FreeRTSO\u7684\u4efb\u52a1\u8c03\u5ea6\u53ea\u505a\u4e00\u4ef6\u4e8b\uff0c\u5c31\u662f\u5728\u7cfb\u7edf\u88ab\u8981\u6c42\u4efb\u52a1\u5207\u6362\u65f6\u627e\u5230\u5728\u5c31\u7eea\u8868\u4e2d\u4f18\u5148\u7ea7\u6700\u9ad8\u7684\u4efb\u52a1\u5e76 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_gspb_post_css":"","footnotes":""},"categories":[1,30],"tags":[],"class_list":["post-44","post","type-post","status-publish","format-standard","hentry","category-uncategorized","category-30"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/monykate.com\/index.php\/wp-json\/wp\/v2\/posts\/44","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/monykate.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/monykate.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/monykate.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/monykate.com\/index.php\/wp-json\/wp\/v2\/comments?post=44"}],"version-history":[{"count":3,"href":"https:\/\/monykate.com\/index.php\/wp-json\/wp\/v2\/posts\/44\/revisions"}],"predecessor-version":[{"id":69,"href":"https:\/\/monykate.com\/index.php\/wp-json\/wp\/v2\/posts\/44\/revisions\/69"}],"wp:attachment":[{"href":"https:\/\/monykate.com\/index.php\/wp-json\/wp\/v2\/media?parent=44"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/monykate.com\/index.php\/wp-json\/wp\/v2\/categories?post=44"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/monykate.com\/index.php\/wp-json\/wp\/v2\/tags?post=44"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}