os_cpu_a.s

三星S34510板子上移植的uCosII源码

;********************************************************************************************************
;                                               uC/OS-II
;                                         The Real-Time Kernel
;
;                          (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
;                                          All Rights Reserved
;
; File : OS_CPU_A.ASM
; By   : Jean J. Labrosse
;********************************************************************************************************

;********************************************************************************************************
;                                               ARM7 Port
;
;                 Target           : ARM7 (Includes ARM7TDMI, ARM710T, ARM720T, ARM740T)
;                 Ported by        : Michael Anburaj
;                 URL              : http://geocities.com/michaelanburaj/    Email : [e-mail]
;
;********************************************************************************************************



        AREA  UCOS_ARM, CODE, READONLY
        
        INCLUDE s3c4510b.s
        
              
	

;*********************************************************************************************************
;                                          START MULTITASKING
;                                       void OSStartHighRdy(void)
;
; Note : OSStartHighRdy() MUST:
;           a) Call OSTaskSwHook() then,
;           b) Set OSRunning to TRUE,
;           c) Switch to the highest priority task.
;*********************************************************************************************************

        IMPORT  OSTaskSwHook
        IMPORT  OSRunning
        IMPORT  OSTCBHighRdy
        IMPORT  OSTCBCur
        
        EXPORT  OSStartHighRdy

OSStartHighRdy  
       ;Call OSTaskswHook
      
        bl OSTaskSwHook             ; Call user defined task switch hook
        
        ; Get current task TCB address
  	    ldr 	r4, =OSTCBCur           ;point to current tcb  

        ; Get highest priority task TCB address
        ldr r5,=OSTCBHighRdy        ; Get highest priority task TCB address
        ldr r5,[r5]                 ; get stack pointer
        ldr sp,[r5]                 ; switch to the new stack
        str r5,[r4]                ; set current tcb = highrdy tcb

        ; Set OSRunning == TRUE
        ldr r4,=OSRunning           ; Indicate that multitasking has started
        mov r5,#1
        strb r5,[r4]
        
        ldmfd sp!,{r4}              ; pop new tasks spsr
        msr SPSR_cxsf,r4
        ldmfd sp!,{r4}              ; pop new tasks psr
        msr CPSR_cxsf,r4
           
        ldmfd sp!,{r0-r12,lr,pc}    ; pop new tasks r0-r12,lr & pc
        

        
;******************************************************************************************

;******************************************************************************************
        
        
        
         EXPORT  OSIntCtxSw
OSIntCtxSw

 
; Interrupt Exit if higher priority task ready to run
; New Task Context switch 
   
       
         
     ldmfd sp!,{r4}            ;pop tass spsr
     msr SPSR_cxsf,r4  
    
     ldmfd sp!,{r4}              ; pop new tasks psr
     msr CPSR_cxsf,r4 
        
     LDMFD sp!,{r0-r12,lr}
     LDMFD sp!,{r0-r12,lr}
   
     SUB	   lr, lr, #4

     
       
     mrs lr,spsr
     msr cpsr_cxsf,lr
      
    
    
   
    	
	b   _OSCtxSw                ; perform the context switch
                                      




;*********************************************************************************************************
;                                PERFORM A CONTEXT SWITCH (From task level)
;                                           void OSCtxSw(void)
;
; Note(s):    Upon entry, 
;             OSTCBCur     points to the OS_TCB of the task to suspend
;             OSTCBHighRdy points to the OS_TCB of the task to resume
;
;*********************************************************************************************************

        IMPORT  OSTCBCur
        IMPORT  OSTaskSwHook
        IMPORT  OSTCBHighRdy
        IMPORT  OSPrioCur
        IMPORT  OSPrioHighRdy

        EXPORT  OSCtxSw

OSCtxSw
; Special optimised code below:
;Save Register of cpu
      
        stmfd sp!,{lr}              ; push pc (lr should be pushed in place of PC)
_OSCtxSw
        stmfd sp!,{lr}  		    ;push lr
        stmfd sp!,{r0-r12}          ; push  register file
        mrs r4,cpsr
        stmfd sp!,{r4}              ; push current psr
        mrs r4,spsr
        stmfd sp!,{r4}              ; push current spsr
       
   ; OSPrioCur = OSPrioHighRdy
        ldr r4,=OSPrioCur
        ldr r5,=OSPrioHighRdy
        ldrb r6,[r5]
        strb r6,[r4]
        
        ; Get current task TCB address
        ldr r4,=OSTCBCur
        ldr r5,[r4]
        str sp,[r5]                 ;存堆栈  store sp in preempted taskss TCB

        bl OSTaskSwHook             ; call Task Switch Hook

        ; Get highest priority task TCB address
        ldr r6,=OSTCBHighRdy
        ldr r6,[r6]
        ldr sp,[r6]                 ;新堆栈  get new tasks stack pointer

        ; OSTCBCur = OSTCBHighRdy
        str r6,[r4]                 ; set new current task TCB address
               
        ldmfd sp!,{r4}              ;弹出堆栈 pop new tasks spsr
        msr SPSR_cxsf,r4
        ldmfd sp!,{r4}              ; pop new tasks psr
        msr CPSR_cxsf,r4
           IMPORT ARMEnableInt
        BL ARMEnableInt
        ldmfd sp!,{r0-r12,lr,pc}    ; pop new tasks r0-r12,lr & pc
        
        
        
;--------------------------------------------------------------------------------------
;*******************************************************************************************
; OSTickISR()
;*******************************************************************************************
		   IMPORT OSIntEnter
		   IMPORT OSTimeTick
		   IMPORT OSIntExit
		   
           EXPORT OSTickISR
OSTickISR

    STMFD sp!,{r0-r12,lr}
          
     mrs r4,cpsr
     stmfd sp!,{r4}              ; push current psr
        
     mrs r4,spsr
     stmfd sp!,{r4}         
                        
     bl OSIntEnter
     
     bl OSTimeTick
     
     bl OSIntExit
      
     ldmfd sp!,{r4}            ;pop tass spsr
     msr SPSR_cxsf,r4 
               	 
     ldmfd sp!,{r4}              ; pop new tasks psr
     msr CPSR_cxsf,r4    
       
     LDMFD sp!,{r0-r12,lr} 
    
     bx lr
     
     


  
       
   END