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@ -40,13 +40,6 @@
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***************************************************************************
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*/
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/*
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Changes between V4.0.0 and V4.0.1
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+ Reduced the code used to setup the initial stack frame.
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+ The kernel no longer has to install or handle the fault interrupt.
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*/
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/*-----------------------------------------------------------
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* Implementation of functions defined in portable.h for the ARM CM3 port.
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*----------------------------------------------------------*/
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@ -55,21 +48,21 @@
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#include "FreeRTOS.h"
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#include "task.h"
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#ifndef configKERNEL_INTERRUPT_PRIORITY
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#define configKERNEL_INTERRUPT_PRIORITY 255
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#endif
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/* Constants required to manipulate the NVIC. */
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#define portNVIC_SYSTICK_CTRL ( ( volatile unsigned portLONG *) 0xe000e010 )
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#define portNVIC_SYSTICK_LOAD ( ( volatile unsigned portLONG *) 0xe000e014 )
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#define portNVIC_INT_CTRL ( ( volatile unsigned portLONG *) 0xe000ed04 )
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#define portNVIC_SYSPRI2 ( ( volatile unsigned portLONG *) 0xe000ed20 )
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#define portNVIC_SYSPRI1 ( ( volatile unsigned portLONG *) 0xe000ed1c )
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#define portNVIC_HARD_FAULT_STATUS 0xe000ed2c
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#define portNVIC_FORCED_FAULT_BIT 0x40000000
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#define portNVIC_SYSTICK_CLK 0x00000004
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#define portNVIC_SYSTICK_INT 0x00000002
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#define portNVIC_SYSTICK_ENABLE 0x00000001
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#define portNVIC_PENDSVSET 0x10000000
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#define portNVIC_PENDSV_PRI 0x00ff0000
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#define portNVIC_SVCALL_PRI 0xff000000
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#define portNVIC_SYSTICK_PRI 0xff000000
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#define portNVIC_PENDSV_PRI ( ( ( unsigned portLONG ) configKERNEL_INTERRUPT_PRIORITY ) << 16 )
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#define portNVIC_SYSTICK_PRI ( ( ( unsigned portLONG ) configKERNEL_INTERRUPT_PRIORITY ) << 24 )
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/* Constants required to set up the initial stack. */
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#define portINITIAL_XPSR ( 0x01000000 )
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@ -78,22 +71,22 @@
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variable. */
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unsigned portBASE_TYPE uxCriticalNesting = 0xaaaaaaaa;
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/* Constant hardware definitions to assist asm code. */
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const unsigned long ulHardFaultStatus = portNVIC_HARD_FAULT_STATUS;
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const unsigned long ulNVICIntCtrl = ( unsigned long ) 0xe000ed04;
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const unsigned long ulForceFaultBit = portNVIC_FORCED_FAULT_BIT;
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const unsigned long ulPendSVBit = portNVIC_PENDSVSET;
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/*
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* Setup the timer to generate the tick interrupts.
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*/
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static void prvSetupTimerInterrupt( void );
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/*
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* Set the MSP/PSP to a known value.
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* Exception handlers.
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*/
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void prvSetMSP( unsigned long ulValue );
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void prvSetPSP( unsigned long ulValue );
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void xPortPendSVHandler( void );
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void xPortSysTickHandler( void );
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void vPortSVCHandler( void );
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/*
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* Start first task is a separate function so it can be tested in isolation.
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*/
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void vPortStartFirstTask( unsigned long ulValue );
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/*-----------------------------------------------------------*/
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@ -108,7 +101,7 @@ portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE
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pxTopOfStack--;
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*pxTopOfStack = ( portSTACK_TYPE ) pxCode; /* PC */
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pxTopOfStack--;
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*pxTopOfStack = 0xfffffffd; /* LR */
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*pxTopOfStack = 0; /* LR */
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pxTopOfStack -= 5; /* R12, R3, R2 and R1. */
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*pxTopOfStack = ( portSTACK_TYPE ) pvParameters; /* R0 */
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pxTopOfStack -= 9; /* R11, R10, R9, R8, R7, R6, R5 and R4. */
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@ -118,19 +111,28 @@ portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE
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}
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/*-----------------------------------------------------------*/
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__asm void prvSetPSP( unsigned long ulValue )
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__asm void vPortSVCHandler( void )
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{
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PRESERVE8
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msr psp, r0
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bx lr;
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ldr r3, =pxCurrentTCB /* Restore the context. */
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ldr r1, [r3] /* Use pxCurrentTCBConst to get the pxCurrentTCB address. */
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ldr r0, [r1] /* The first item in pxCurrentTCB is the task top of stack. */
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ldmia r0!, {r1, r4-r11} /* Pop the registers that are not automatically saved on exception entry and the critical nesting count. */
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ldr r2, =uxCriticalNesting /* Restore the critical nesting count used by the task. */
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str r1, [r2]
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msr psp, r0 /* Restore the task stack pointer. */
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orr r14, #0xd
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bx r14
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}
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/*-----------------------------------------------------------*/
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__asm void prvSetMSP( unsigned long ulValue )
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__asm void vPortStartFirstTask( unsigned long ulValue )
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{
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PRESERVE8
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msr msp, r0
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bx lr;
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msr msp, r0 /* Set the msp back to the start of the stack. */
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svc 0 /* System call to start first task. */
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}
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/*-----------------------------------------------------------*/
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@ -139,22 +141,16 @@ __asm void prvSetMSP( unsigned long ulValue )
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*/
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portBASE_TYPE xPortStartScheduler( void )
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{
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/* Start the timer that generates the tick ISR. Interrupts are disabled
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here already. */
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prvSetupTimerInterrupt();
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/* Make PendSV, CallSV and SysTick the lowest priority interrupts. */
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/* Make PendSV, CallSV and SysTick the same priroity as the kernel. */
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*(portNVIC_SYSPRI2) |= portNVIC_PENDSV_PRI;
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*(portNVIC_SYSPRI2) |= portNVIC_SYSTICK_PRI;
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*(portNVIC_SYSPRI1) |= portNVIC_SVCALL_PRI;
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/* Start the timer that generates the tick ISR. Interrupts are disabled
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here already. */
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prvSetupTimerInterrupt();
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/* Start the first task. */
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prvSetPSP( 0 );
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prvSetMSP( *((unsigned portLONG *) 0 ) );
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*(portNVIC_INT_CTRL) |= portNVIC_PENDSVSET;
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/* Enable interrupts */
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portENABLE_INTERRUPTS();
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vPortStartFirstTask( *((unsigned portLONG *) 0 ) );
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/* Should not get here! */
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return 0;
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@ -171,30 +167,17 @@ void vPortEndScheduler( void )
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void vPortYieldFromISR( void )
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{
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/* Set a PendSV to request a context switch. */
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*(portNVIC_INT_CTRL) |= portNVIC_PENDSVSET;
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portENABLE_INTERRUPTS();
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}
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/*-----------------------------------------------------------*/
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__asm void vPortDisableInterrupts( void )
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{
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PRESERVE8
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cpsid i;
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bx lr;
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}
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/*-----------------------------------------------------------*/
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*(portNVIC_INT_CTRL) |= portNVIC_PENDSVSET;
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__asm void vPortEnableInterrupts( void )
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{
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PRESERVE8
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cpsie i;
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bx lr;
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/* This function is also called in response to a Yield(), so we want
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the yield to occur immediately. */
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portENABLE_INTERRUPTS();
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}
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/*-----------------------------------------------------------*/
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void vPortEnterCritical( void )
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{
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vPortDisableInterrupts();
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portDISABLE_INTERRUPTS();
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uxCriticalNesting++;
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}
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/*-----------------------------------------------------------*/
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@ -204,7 +187,7 @@ void vPortExitCritical( void )
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uxCriticalNesting--;
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if( uxCriticalNesting == 0 )
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{
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vPortEnableInterrupts();
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portENABLE_INTERRUPTS();
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}
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}
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/*-----------------------------------------------------------*/
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@ -217,81 +200,46 @@ __asm void xPortPendSVHandler( void )
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PRESERVE8
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/* Start first task if the stack has not yet been setup. */
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mrs r0, psp
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cbz r0, no_save
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mrs r0, psp
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/* Save the context into the TCB. */
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stmdb r0!, {r4-r11}
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sub r0, r0, #0x04
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ldr r1, =uxCriticalNesting
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ldr r2, =pxCurrentTCB
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ldr r3, =pxCurrentTCB /* Get the location of the current TCB. */
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ldr r2, [r3]
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ldr r1, =uxCriticalNesting /* Save the remaining registers and the critical nesting count onto the task stack. */
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ldr r1, [r1]
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ldr r2, [r2]
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str r1, [r0]
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str r0, [r2]
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stmdb r0!, {r1,r4-r11}
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str r0, [r2] /* Save the new top of stack into the first member of the TCB. */
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no_save;
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/* Find the task to execute. */
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push {r14}
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cpsid i
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bl vTaskSwitchContext
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cpsie i
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pop {r14}
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/* Restore the context. */
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ldr r1, =pxCurrentTCB
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ldr r1, [r1];
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ldr r0, [r1];
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ldmia r0!, {r1, r4-r11}
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stmdb sp!, {r3, r14}
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bl vTaskSwitchContext
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ldmia sp!, {r3, r14}
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ldr r1, [r3]
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ldr r2, =uxCriticalNesting
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str r1, [r2]
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ldr r2, [r2]
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msr psp, r0
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orr r14, #0xd
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ldr r0, [r1] /* The first item in pxCurrentTCB is the task top of stack. */
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ldmia r0!, {r1, r4-r11} /* Pop the registers and the critical nesting count. */
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str r1, [r2] /* Save the new critical nesting value into ulCriticalNesting. */
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msr psp, r0
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orr r14, #0xd
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/* Exit with interrupts in the state required by the task. */
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cbnz r2, sv_disable_interrupts
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cbnz r1, sv_disable_interrupts /* If the nesting count is greater than 0 we need to exit with interrupts masked. */
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bx r14
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sv_disable_interrupts;
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cpsid i
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bx r14
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sv_disable_interrupts
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mov r1, #configKERNEL_INTERRUPT_PRIORITY
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msr basepri, r1
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bx r14
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}
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/*-----------------------------------------------------------*/
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__asm void xPortSysTickHandler( void )
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void xPortSysTickHandler( void )
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{
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extern vTaskIncrementTick
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PRESERVE8
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/* Call the scheduler tick function. */
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push {r14}
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cpsid i
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bl vTaskIncrementTick
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cpsie i
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pop {r14}
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vTaskIncrementTick();
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/* If using preemption, also force a context switch. */
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#if configUSE_PREEMPTION == 1
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extern vPortYieldFromISR
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push {r14}
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bl vPortYieldFromISR
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pop {r14}
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*(portNVIC_INT_CTRL) |= portNVIC_PENDSVSET;
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#endif
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/* Exit with interrupts in the correct state. */
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ldr r2, =uxCriticalNesting
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ldr r2, [r2]
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cbnz r2, tick_disable_interrupts
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bx r14
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tick_disable_interrupts;
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cpsid i
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bx r14
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}
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/*-----------------------------------------------------------*/
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@ -305,5 +253,26 @@ void prvSetupTimerInterrupt( void )
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*(portNVIC_SYSTICK_LOAD) = configCPU_CLOCK_HZ / configTICK_RATE_HZ;
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*(portNVIC_SYSTICK_CTRL) = portNVIC_SYSTICK_CLK | portNVIC_SYSTICK_INT | portNVIC_SYSTICK_ENABLE;
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}
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/*-----------------------------------------------------------*/
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__asm void vPortSetInterruptMask( void )
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{
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PRESERVE8
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push { r0 }
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mov r0, #configKERNEL_INTERRUPT_PRIORITY
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msr basepri, r0
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pop { r0 }
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}
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/*-----------------------------------------------------------*/
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__asm void vPortClearInterruptMask( void )
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{
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PRESERVE8
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push { r0 }
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mov r0, #0
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msr basepri, r0
|
|
|
|
|
pop { r0 }
|
|
|
|
|
}
|
|
|
|
|