📄 os_cpu_asm.s
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;//*********************************************************************************************************
;// uC/OS-II
;// The Real-Time Kernel
;//
;// (c) Copyright 1992-2003, Jean J. Labrosse, Weston, FL
;// All Rights Reserved
;//
;// ARM920T Port
;// ADS v1.2 Compiler
;// Samsung S3C2440A
;//
;// File : os_cpu_a.s refrence to ucos application note for arm AN-1014
;// Des : S3C2440 uC/OS-II Port
;// by : tangxiaofeng xidian 503
;// History :
;// OSCtxSw(), OSIntCtxSw() OSStartHighRdy() OS_CPU_IRQ_ISR() OSTickISR()
;//******************************************************************************************************** */
SRCPND EQU 0x4a000000 ;// Source pending
INTPND EQU 0x4a000010 ;// Interrupt request status
rEINTPEND EQU 0x560000a8
INTOFFSET EQU 0x4a000014
USERMODE EQU 0x10
FIQMODE EQU 0x11
IRQMODE EQU 0x12
SVCMODE EQU 0x13
ABORTMODE EQU 0x17
UNDEFMODE EQU 0x1b
MODEMASK EQU 0x1f
NOINT EQU 0xc0
;//*********************************************************************************************************
;// EXPORT and EXTERNAL REFERENCES
;//*********************************************************************************************************/
IMPORT OSRunning
IMPORT OSTCBCur
IMPORT OSTCBHighRdy
IMPORT OSPrioCur
IMPORT OSPrioHighRdy
IMPORT OSIntNesting
IMPORT OSIntEnter
IMPORT OSIntExit
IMPORT OSTaskSwHook
IMPORT OSTimeTick
IMPORT HandleEINT0
EXPORT OSStartHighRdy
EXPORT OSCtxSw
EXPORT OSTickISR
EXPORT OSIntCtxSw
EXPORT OSCPUSaveSR
EXPORT OSCPURestoreSR
EXPORT OS_CPU_IRQ_ISR
AREA UCOS_ARM, CODE, READONLY
;//*********************************************************************************************************
;// START MULTITASKING
;// void OSStartHighRdy(void)
;//
;// The stack frame is assumed to look as follows:
;//
;// Entry Point(Task Name) (High memory)
;// LR(R14)
;// R12
;// R11
;// R10
;// R9
;// R8
;// R7
;// R6
;// R5
;// R4
;// R3
;// R2
;// R1
;// R0 : argument
;// OSTCBHighRdy->OSTCBStkPtr --> CPSR (Low memory)
;//
;// Note : OSStartHighRdy() MUST:
;// a) Call OSTaskSwHook() then,
;// b) Set OSRunning to TRUE,
;// c) Switch to the highest priority task.
;//********************************************************************************************************** */
OSStartHighRdy
;//----------------------------------------------------------------------------------
;// OSRunning = TRUE;//
;//----------------------------------------------------------------------------------
;//MSR CPSR_cxsf,#SVCMODE|NOINT ;//Switch to SVC mode with IRQ&FIQ disable
BL OSTaskSwHook ;//Call user define Task switch hook
LDR R0, =OSRunning ;// OSRunning =TRUE
MOV R1, #1
STRB R1, [R0]
;//----------------------------------------------------------------------------------
;// SP = OSTCBHighRdy->OSTCBStkPtr;//
;//----------------------------------------------------------------------------------
LDR R0, =OSTCBHighRdy
LDR R0, [R0]
LDR SP, [R0]
;//----------------------------------------------------------------------------------
;// Prepare to return to proper mode
;//----------------------------------------------------------------------------------
LDMFD SP!, {R0}
MSR SPSR_cxsf, R0
LDMFD SP!, {R0-R12, LR, PC}^
;//**********************************************************************************************************
;// PERFORM A CONTEXT SWITCH (From task level)
;// void OSCtxSw(void)
;//
;// Note(s): 1) Upon entry:
;// OSTCBCur points to the OS_TCB of the task to suspend
;// OSTCBHighRdy points to the OS_TCB of the task to resume
;//
;// 2) The stack frame of the task to suspend looks as follows:
;//
;// PC (High memory)
;// LR(R14)
;// R12
;// R11
;// R10
;// R9
;// R8
;// R7
;// R6
;// R5
;// R4
;// R3
;// R2
;// R1
;// R0
;// OSTCBCur->OSTCBStkPtr ----> CPSR (Low memory)
;//
;//
;// 3) The stack frame of the task to resume looks as follows:
;//
;// PC (High memory)
;// LR(R14)
;// R12
;// R11
;// R10
;// R9
;// R8
;// R7
;// R6
;// R5
;// R4
;// R3
;// R2
;// R1
;// R0
;// OSTCBHighRdy->OSTCBStkPtr ----> CPSR (Low memory)
;//*********************************************************************************************************/
OSCtxSw
STMFD SP!, {LR} ;//PC
STMFD SP!, {R0-R12, LR} ;//R0-R12 LR
MRS R0, CPSR ;//Push CPSR
STMFD SP!, {R0}
;//----------------------------------------------------------------------------------
;// OSTCBCur->OSTCBStkPtr = SP
;//----------------------------------------------------------------------------------
LDR R0, =OSTCBCur
LDR R0, [R0]
STR SP, [R0]
;//----------------------------------------------------------------------------------
;// OSTaskSwHook();//
;//---------------------------------------------------------------------------------
BL OSTaskSwHook
;//----------------------------------------------------------------------------------
;// OSTCBCur = OSTCBHighRdy;//
;//----------------------------------------------------------------------------------
LDR R0, =OSTCBHighRdy
LDR R1, =OSTCBCur
LDR R0, [R0]
STR R0, [R1]
;//----------------------------------------------------------------------------------
;// OSPrioCur = OSPrioHighRdy;//
;//----------------------------------------------------------------------------------
LDR R0, =OSPrioHighRdy
LDR R1, =OSPrioCur
LDRB R0, [R0]
STRB R0, [R1]
;//----------------------------------------------------------------------------------
;// OSTCBHighRdy->OSTCBStkPtr;//
;//----------------------------------------------------------------------------------
LDR R0, =OSTCBHighRdy
LDR R0, [R0]
LDR SP, [R0]
;//----------------------------------------------------------------------------------
;//Restore New task context
;//----------------------------------------------------------------------------------
LDMFD SP!, {R0} ;//POP CPSR
MSR SPSR_cxsf, R0
LDMFD SP!, {R0-R12, LR, PC}^
;//*********************************************************************************************************
;// TICK HANDLER
;//
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