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Performance optimisation.

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This commit is contained in:
Richard Barry 2008-03-23 15:54:50 +00:00
parent a8d03f24e3
commit 58905b6fb4
1 changed files with 54 additions and 108 deletions
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154
Source/portable/GCC/ARM_CM3/port.c
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@ -40,19 +40,6 @@
***************************************************************************
*/
/*
Changes between V4.0.0 and V4.0.1
+ Reduced the code used to setup the initial stack frame.
+ The kernel no longer has to install or handle the fault interrupt.
Change from V4.4.0:
+ Introduced usage of configKERNEL_INTERRUPT_PRIORITY macro to set the
interrupt priority used by the kernel.
*/
/*-----------------------------------------------------------
* Implementation of functions defined in portable.h for the ARM CM3 port.
*----------------------------------------------------------*/
@ -100,13 +87,13 @@ static void prvSetupTimerInterrupt( void );
* Exception handlers.
*/
void xPortPendSVHandler( void ) __attribute__ (( naked ));
void xPortSysTickHandler( void ) __attribute__ (( naked ));
void xPortSysTickHandler( void );
void vPortSVCHandler( void ) __attribute__ (( naked ));
/*
* Set the MSP/PSP to a known value.
* Start first task is a separate function so it can be tested in isolation.
*/
void prvSetMSP( unsigned long ulValue ) __attribute__ (( naked ));
void prvSetPSP( unsigned long ulValue ) __attribute__ (( naked ));
void vPortStartFirstTask( unsigned long ulValue ) __attribute__ (( naked ));
/*-----------------------------------------------------------*/
@ -131,17 +118,36 @@ portSTACK_TYPE *pxPortInitialiseStack( portSTACK_TYPE *pxTopOfStack, pdTASK_CODE
}
/*-----------------------------------------------------------*/
void prvSetPSP( unsigned long ulValue )
void vPortSVCHandler( void )
{
asm volatile( "msr psp, r0" );
asm volatile( "bx lr" );
asm volatile (
" ldr r3, pxCurrentTCBConst2 \n" /* Restore the context. */
" ldr r1, [r3] \n" /* Use pxCurrentTCBConst to get the pxCurrentTCB address. */
" ldr r0, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. */
" ldmia r0!, {r1, r4-r11} \n" /* Pop the registers that are not automatically saved on exception entry and the critical nesting count. */
" ldr r2, uxCriticalNestingConst2 \n" /* Restore the critical nesting count used by the task. */
" str r1, [r2] \n"
" msr psp, r0 \n" /* Restore the task stack pointer. */
" orr r14, #0xd \n"
" bx r14 \n"
" \n"
" .align 2 \n"
"pxCurrentTCBConst2: .word pxCurrentTCB \n"
"uxCriticalNestingConst2: .word uxCriticalNesting \n"
);
}
/*-----------------------------------------------------------*/
void prvSetMSP( unsigned long ulValue )
void vPortStartFirstTask( unsigned long ulValue )
{
asm volatile( "msr msp, r0" );
asm volatile( "bx lr" );
/* ulValue is used from the asm code, but the compiler does not know
this so remove the warning. */
( void ) ulValue;
asm volatile(
" msr msp, r0 \n" /* Set the msp back to the start of the stack. */
" svc 0 \n" /* System call to start first task. */
);
}
/*-----------------------------------------------------------*/
@ -159,12 +165,7 @@ portBASE_TYPE xPortStartScheduler( void )
prvSetupTimerInterrupt();
/* Start the first task. */
prvSetPSP( 0 );
prvSetMSP( *((unsigned portLONG *) 0 ) );
*(portNVIC_INT_CTRL) |= portNVIC_PENDSVSET;
/* Enable interrupts */
portENABLE_INTERRUPTS();
vPortStartFirstTask( *((unsigned portLONG *) 0 ) );
/* Should not get here! */
return 0;
@ -208,36 +209,33 @@ void vPortExitCritical( void )
void xPortPendSVHandler( void )
{
/* Start first task if the stack has not yet been setup. */
/* This is a naked function. */
__asm volatile
(
" mrs r0, psp \n"
" cbz r0, no_save \n"
" \n" /* Save the context into the TCB. */
" stmdb r0!, {r4-r11} \n"
" sub r0, #0x04 \n"
" ldr r1, uxCriticalNestingConst \n"
" ldr r2, pxCurrentTCBConst \n"
" ldr r1, [r1] \n"
" ldr r2, [r2] \n"
" str r1, [r0] \n"
" str r0, [r2] \n"
" \n"
"no_save:\n"
" push {r14} \n"
" bl vPortSwitchContext \n"
" pop {r14} \n"
" \n" /* Restore the context. */
" ldr r1, pxCurrentTCBConst \n"
" ldr r3, pxCurrentTCBConst \n" /* Get the location of the current TCB. */
" ldr r2, [r3] \n"
" \n"
" ldr r1, uxCriticalNestingConst \n" /* Save the remaining registers and the critical nesting count onto the task stack. */
" ldr r1, [r1] \n"
" ldr r0, [r1] \n"
" ldmia r0!, {r1, r4-r11} \n"
" stmdb r0!, {r1,r4-r11} \n"
" str r0, [r2] \n" /* Save the new top of stack into the first member of the TCB. */
" \n"
" stmdb sp!, {r3, r14} \n"
" bl vTaskSwitchContext \n"
" ldmia sp!, {r3, r14} \n"
" \n" /* Restore the context, including the critical nesting count. */
" ldr r1, [r3] \n"
" ldr r2, uxCriticalNestingConst \n"
" str r1, [r2] \n"
" ldr r0, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. */
" ldmia r0!, {r1, r4-r11} \n" /* Pop the registers and the critical nesting count. */
" str r1, [r2] \n" /* Save the new critical nesting value into ulCriticalNesting. */
" msr psp, r0 \n"
" orr r14, #0xd \n"
" \n" /* Exit with interrupts in the state required by the task. */
" cbnz r1, sv_disable_interrupts \n"
" cbnz r1, sv_disable_interrupts \n" /* If the nesting count is greater than 0 we need to exit with interrupts masked. */
" bx r14 \n"
" \n"
"sv_disable_interrupts: \n"
@ -255,47 +253,12 @@ void xPortPendSVHandler( void )
void xPortSysTickHandler( void )
{
extern void vTaskIncrementTick( void );
extern void vPortYieldFromISR( void );
/* Call the scheduler tick function. */
__asm volatile
(
" push {r14} \n"
" bl vPortIncrementTick \n"
" pop {r14}"
);
vTaskIncrementTick();
/* If using preemption, also force a context switch. */
#if configUSE_PREEMPTION == 1
__asm volatile
(
" push {r14} \n"
" bl vPortYieldFromISR \n"
" pop {r14}"
);
*(portNVIC_INT_CTRL) |= portNVIC_PENDSVSET;
#endif
/* Exit with interrupts in the correct state. */
__asm volatile
(
" ldr r2, uxCriticalNestingConst2 \n"
" ldr r2, [r2] \n"
" cbnz r2, tick_disable_interrupts \n"
" bx r14"
);
__asm volatile
(
"tick_disable_interrupts: \n"
" ldr r1, =ulKernelPriority \n"
" ldr r1, [r1] \n"
" msr basepri, r1 \n"
" bx r14 \n"
" \n"
" .align 2 \n"
"uxCriticalNestingConst2: .word uxCriticalNesting"
);
}
/*-----------------------------------------------------------*/
@ -311,20 +274,3 @@ void prvSetupTimerInterrupt( void )
}
/*-----------------------------------------------------------*/
void vPortSwitchContext( void )
{
vPortSetInterruptMask();
vTaskSwitchContext();
vPortClearInterruptMask();
}
/*-----------------------------------------------------------*/
void vPortIncrementTick( void )
{
vPortSetInterruptMask();
vTaskIncrementTick();
vPortClearInterruptMask();
}
/*-----------------------------------------------------------*/