?? os_cpu_a.asm
字號:
LDR R4, =OSRunning ; OSRunning = TRUE
MOV R5, #1
STRB R5, [R4]
LDR R4, =NVIC_INT_CTRL ; trigger the PendSV exception
; 觸發(fā)軟件中斷
LDR R5, =NVIC_PENDSVSET
STR R5, [R4]
CPSIE I ; enable interrupts at processor
; level使能所有優(yōu)先級的中斷
OSStartHang
B OSStartHang
;*********************************************************************************************************
;** Function name: OSCtxSw
;** Descriptions: Perform a contex switch from task level 任務級上下文切換
;** Input parameters: None 無
;** Output parameters: None 無
;** Returned value: None 無
;** Created by: Steven Zhou 周紹剛
;** Created Date: 2007.01.18
;**-------------------------------------------------------------------------------------------------------
;** Modified by: Ni Likao 倪力考
;** Modified date: 2007.11.02
;**-------------------------------------------------------------------------------------------------------
;*********************************************************************************************************
OSCtxSw
PUSH {R4, R5}
LDR R4, =NVIC_INT_CTRL ; trigger the PendSV exception
; 觸發(fā)軟件中斷
LDR R5, =NVIC_PENDSVSET
STR R5, [R4]
POP {R4, R5}
BX LR
;*********************************************************************************************************
;** Function name: OSIntCtxSw
;** Descriptions: called by OSIntExit() when it determines a context switch is needed as the
;** result of an interrupt.
;** 中斷級任務切換
;** Input parameters: None 無
;** Output parameters: None 無
;** Returned value: None 無
;** Created by: Steven Zhou 周紹剛
;** Created Date: 2007.01.18
;**-------------------------------------------------------------------------------------------------------
;** Modified by: Ni Likao 倪力考
;** Modified date: 2007.11.02
;**-------------------------------------------------------------------------------------------------------
;*********************************************************************************************************
OSIntCtxSw
PUSH {R4, R5}
LDR R4, =NVIC_INT_CTRL ; trigger the PendSV exception
; 觸發(fā)軟件中斷
LDR R5, =NVIC_PENDSVSET
STR R5, [R4]
POP {R4, R5}
BX LR
NOP
;*********************************************************************************************************
;** Function name: OSPendSV
;** Descriptions: Used to cause a context switch 用于上下文切換
;** Input parameters: None 無
;** Output parameters: None 無
;** Returned value: None 無
;** Created by: Steven Zhou 周紹剛
;** Created Date: 2007.01.18
;**-------------------------------------------------------------------------------------------------------
;** Modified by: Ni Likao 倪力考
;** Modified date: 2007.11.02
;**-------------------------------------------------------------------------------------------------------
;*********************************************************************************************************
OSPendSV
IF OS_CRITICAL_INT_PRIO > 0 ; disable interupt 禁能中斷
MRS R3, BASEPRI
LDR R1, =OS_CRITICAL_INT_PRIO
MSR BASEPRI, R1
ELSE
MRS R3, PRIMASK
CPSID I
ENDIF
MRS R0, PSP ; PSP is process stack pointer
; PSP是任務的堆棧指針
CBZ R0, OSPendSV_nosave ; skip register save the first
; time第一次跳過保存
SUB R0, R0, #0x20 ; save remaining regs r4-11 on
; process stack 保存r4-r11
STM R0, {R4-R11}
LDR R4, =OSTCBCur ; OSTCBCur->OSTCBStkPtr = SP;
LDR R4, [R4]
STR R0, [R4] ; R0 is SP of process being
; switched outR0是被切換開的任務
; 的堆棧指針
OSPendSV_nosave
PUSH {R14} ; need to save LR exc_return
; value保存LR返回值
LDR R0, =OSTaskSwHook ; OSTaskSwHook();
BLX R0
POP {R14}
LDR R4, =OSPrioCur ; OSPrioCur = OSPrioHighRdy
LDR R5, =OSPrioHighRdy
LDRB R6, [R5]
STRB R6, [R4]
LDR R4, =OSTCBCur ; OSTCBCur = OSTCBHighRdy;
LDR R6, =OSTCBHighRdy
LDR R6, [R6]
STR R6, [R4]
LDR R0, [R6] ; SP = OSTCBHighRdy->OSTCBStkPtr;
LDM R0, {R4-R11} ; restore r4-11 from new process
; stack 從新任務的堆棧恢復r4-r11
ADD R0, R0, #0x20
MSR PSP, R0 ; load PSP with new process SP
; 從新任務的堆棧恢復PSP
ORR LR, LR, #0x04 ; ensure exception return uses
; PSP確保返回后使用PSP
IF OS_CRITICAL_INT_PRIO > 0 ; restore interrupts 恢復中斷
MSR BASEPRI, R3
ELSE
MSR PRIMASK, R3
ENDIF
BX LR ; exception return will restore
; remaining context
; 返回時會恢復剩下的上下文
NOP
;*********************************************************************************************************
;** Function name: IntDisAll
;** Descriptions: Disable all interrupts from the interrupt controller 關閉中斷控制器的所有中斷
;** Input parameters: None 無
;** Output parameters: None 無
;** Returned value: None 無
;** Created by: Steven Zhou 周紹剛
;** Created Date: 2007.12.12
;**-------------------------------------------------------------------------------------------------------
;** Modified by:
;** Modified date:
;**-------------------------------------------------------------------------------------------------------
;*********************************************************************************************************
intDisAll
CPSID I
BX LR
ALIGN
END
;*********************************************************************************************************
; END FILE
;*********************************************************************************************************
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