os_cpu_a.s.bak

这是一个u/COS-II v2.80,三星44B0的移植的源码。

;              e) Restore the new task's context from the new task's stack
;              f) Return to new task's code
;
;           3) Upon entry: 
;              OSTCBCur      points to the OS_TCB of the task to suspend
;              OSTCBHighRdy  points to the OS_TCB of the task to resume
;*********************************************************************************************************

;        RSEG CODE:CODE:NOROOT(2)
;        CODE32

OSIntCtxSw
        BL      OSTaskSwHook     ; OSTaskSwHook();
                

        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     SP,[R6]                 ; SP = OSTCBHighRdy->OSTCBStkPtr;

                                        ; RESTORE NEW TASK'S CONTEXT
        LDMFD   SP!, {R4}               ;    Pop new task's CPSR
        MSR     SPSR_cxsf, R4
        
        LDMFD   SP!, {R0-R12,LR,PC}^    ;    Pop new task's context

;*********************************************************************************************************
;                                      IRQ Interrupt Service Routine
;*********************************************************************************************************

;       RSEG CODE:CODE:NOROOT(2)
;        CODE32

OS_CPU_IRQ_ISR
   

        STMFD   SP!, {R1-R3}                   ; PUSH WORKING REGISTERS ONTO IRQ STACK                     
        
        MOV     R1, SP                         ; Save   IRQ stack pointer
        
        ADD     SP, SP,#12                     ; Adjust IRQ stack pointer 
        
        SUB     R2, LR,#4                      ; Adjust PC for return address to task

        MRS     R3, SPSR                       ; Copy SPSR (i.e. interrupted task's CPSR) to R3
        
        MSR     CPSR_c, #(NO_INT | SVC32_MODE) ; Change to SVC mode

                                               ; SAVE TASK'S CONTEXT ONTO TASK'S STACK
        STMFD   SP!, {R2}                      ;    Push task's Return PC
        STMFD   SP!, {LR}                      ;    Push task's LR
        STMFD   SP!, {R4-R12}                  ;    Push task's R12-R4
        
        LDMFD   R1!, {R4-R6}                   ;    Move task's R1-R3 from IRQ stack to SVC stack
        STMFD   SP!, {R4-R6}
        STMFD   SP!, {R0}                      ;    Push task's R0    onto task's stack
        STMFD   SP!, {R3}                      ;    Push task's CPSR (i.e. IRQ's SPSR)
                
                                               ; HANDLE NESTING COUNTER
        LDR     R0, =OSIntNesting            ; OSIntNesting++;
        LDRB    R1, [R0]
        ADD     R1, R1,#1
        STRB    R1, [R0]

        CMP     R1, #1                         ; if (OSIntNesting == 1) {
        BNE     OS_CPU_IRQ_ISR_1

        LDR     R4, =OSTCBCur                ;     OSTCBCur->OSTCBStkPtr = SP
        LDR     R5, [R4]
        STR     SP, [R5]                       ; }

OS_CPU_IRQ_ISR_1
        MSR     CPSR_c, #(NO_INT | IRQ32_MODE) ; Change to IRQ mode (to use the IRQ stack to handle interrupt)
        
        BL      ISR_IrqHandler              ;OS_CPU_IRQ_ISR_Handler  ; OS_CPU_IRQ_ISR_Handler();
                  
        MSR     CPSR_c, #(NO_INT | SVC32_MODE) ; Change to SVC mode
        
        BL      OSIntExit                      ; OSIntExit();
           
                                               ; RESTORE NEW TASK'S CONTEXT
        LDMFD   SP!, {R4}                      ;    Pop new task's CPSR
        MSR     SPSR_cxsf, R4
        
        LDMFD   SP!, {R0-R12,LR,PC}^           ;    Pop new task's context

;*********************************************************************************************************
;                                      FIQ Interrupt Service Routine
;*********************************************************************************************************

       ; RSEG CODE:CODE:NOROOT(2)
       ; CODE32

;OS_CPU_FIQ_ISR
                                        
        ;STMFD   SP!, {R1-R3}                   ; PUSH WORKING REGISTERS ONTO FIQ STACK                     
       ; 
       ; MOV     R1, SP                         ; Save   FIQ stack pointer
       ; 
       ; ADD     SP, SP,#12                     ; Adjust FIQ stack pointer 
       ; 
       ;SUB     R2, LR,#4                      ; Adjust PC for return address to task

       ; MRS     R3, SPSR                       ; Copy SPSR (i.e. interrupted task's CPSR) to R3
        
       ; MSR     CPSR_c, #(NO_INT | SVC32_MODE) ; Change to SVC mode

                                               ; SAVE TASK'S CONTEXT ONTO TASK'S STACK
       ; STMFD   SP!, {R2}                      ;    Push task's Return PC
       ; STMFD   SP!, {LR}                      ;    Push task's LR
       ; STMFD   SP!, {R4-R12}                  ;    Push task's R12-R4
        
       ; LDMFD   R1!, {R4-R6}                   ;    Move task's R1-R3 from FIQ stack to SVC stack
       ; STMFD   SP!, {R4-R6}
       ; STMFD   SP!, {R0}                      ;    Push task's R0    onto task's stack
       ; STMFD   SP!, {R3}                      ;    Push task's CPSR (i.e. FIQ's SPSR)
       ;         
                                               ; HANDLE NESTING COUNTER
       ; LDR     R0, ??OS_IntNesting            ; OSIntNesting++;
      ; LDRB    R1, [R0]
       ; ADD     R1, R1,#1
      ;  STRB    R1, [R0]

      ;  CMP     R1, #1                         ; if (OSIntNesting == 1) {
      ;  BNE     OS_CPU_FIQ_ISR_1

       ; LDR     R4, ??OS_TCBCur                ;     OSTCBCur->OSTCBStkPtr = SP
       ; LDR     R5, [R4]
       ; STR     SP, [R5]                       ; }

;OS_CPU_FIQ_ISR_1
       ; MSR     CPSR_c, #(NO_INT | FIQ32_MODE) ; Change to FIQ mode (to use the FIQ stack to handle interrupt)
        
       ; LDR     R0, ??OS_CPU_FIQ_ISR_Handler   ; OS_CPU_FIQ_ISR_Handler();
       ; MOV     LR, PC
       ; BX      R0            
        
       ; MSR     CPSR_c, #(NO_INT | SVC32_MODE) ; Change to SVC mode
        
       ; LDR     R0, ??OS_IntExit               ; OSIntExit();
       ; MOV     LR, PC
       ; BX      R0            
        
                                               ; RESTORE NEW TASK'S CONTEXT
       ; LDMFD   SP!, {R4}                      ;    Pop new task's CPSR
       ; MSR     SPSR_cxsf, R4
        
       ; LDMFD   SP!, {R0-R12,LR,PC}^           ;    Pop new task's context

;*********************************************************************************************************
;                                     POINTERS TO VARIABLES
;*********************************************************************************************************

;        DATA
             
;??OS_TaskSwHook:
;        DC32    OSTaskSwHook

;??OS_CPU_IRQ_ISR_Handler:
;        DC32    OS_CPU_IRQ_ISR_Handler

;??OS_CPU_FIQ_ISR_Handler:
;        DC32    OS_CPU_FIQ_ISR_Handler

;??OS_IntExit:
;        DC32    OSIntExit

;??OS_IntNesting:
;        DC32    OSIntNesting

;??OS_PrioCur:
;        DC32    OSPrioCur

;??OS_PrioHighRdy:
;        DC32    OSPrioHighRdy

;??OS_Running:
;        DC32    OSRunning

;??OS_TCBCur:
;        DC32    OSTCBCur

;??OS_TCBHighRdy:
;        DC32    OSTCBHighRdy

        END