?? os_cpu_a.s
字號:
;arm ml674000
;arm init.s
;data 21/07/05
SwiV EQU 0x08
IrqV EQU 0x18
FiqV EQU 0x1C
NoInt EQU 0x80
SVC32Mode EQU 0x13
IRQ32Mode EQU 0x12
FIQ32Mode EQU 0x11
OSEnterSWI EQU 0x00
BIT_TIMER0 EQU (0x1<<13)
I_ISPC EQU 0x1e00024
INTMSK EQU 0x1e0000c
AREA |subr|, CODE, READONLY
ENTRY
; External symbols we need the addresses of
;IMPORT need_to_swap_context
;IMPORT IrqStart
IMPORT OSTimeTick
;IMPORT IrqFinish
;IMPORT OutDebug
;IMPORT BreakPoint
EXPORT IRQContextSwap
;;;;;;void OSCtxSW(void)
;;;;;;note 3
IMPORT OSTCBCur
IMPORT OSTaskSwHook
IMPORT OSTCBHighRdy
IMPORT OSPrioCur
IMPORT OSPrioHighRdy
EXPORT OSCtxSw
addr_OSTCBCur DCD OSTCBCur
addr_OSTCBHighRdy DCD OSTCBHighRdy
addr_OSPrioCur DCD OSPrioCur
addr_OSPrioHighRdy DCD OSPrioHighRdy
OSCtxSw
stmfd sp!,{lr}
stmfd sp!,{r0-r12,lr}
mrs r4,spsr
stmfd sp!,{r4}
; 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] ; store sp in preempted tasks's TCB
bl OSTaskSwHook ; call Task Switch Hook
; Get highest priority task TCB address
ldr r6,=OSTCBHighRdy
ldr r6,[r6]
ldr sp,[r6] ; get new task's stack pointer
; OSTCBCur = OSTCBHighRdy
str r6,[r4] ; set new current task TCB address
ldmfd sp!,{r4} ; pop new task's spsr
msr SPSR_cxsf,r4
ldmfd sp!,{r4} ; pop new task's psr
msr CPSR_cxsf,r4
ldmfd sp!,{r0-r12,lr,pc} ; pop new task's r0-r12,lr & pc
;;;;void OSIntCtxSw(void)
IMPORT OSIntCtxSwFlag
EXPORT OSIntCtxSw
OSIntCtxSw
;OSIntCtxSwFlag = True
ldr r0,=OSIntCtxSwFlag
mov r1,#1
str r1,[r0]
mov pc,lr
IRQContextSwap
LDMIA sp!,{a1-v1, lr}
SUBS pc, lr, #4
SUB lr, lr, #4
MOV r12, lr
MRS lr, SPSR
AND lr, lr, #0xFFFFFFE0
ORR lr, lr, #0xD3
MSR CPSR_cxsf, lr
EXPORT __Tick
__Tick
STMDB sp!,{r0-r11,lr}
;interrupt disable(not nessary)
mrs r0, CPSR
orr r0, r0, #0x80 ; and set IRQ disable flag
msr CPSR_cxsf, r0
;End of interrupt
;(Clear pending bit of INTPEND that don't accessed it.)
; rI_ISPC= BIT_TIMER0;
LDR r0, =I_ISPC
LDR r1, =BIT_TIMER0
STR r1, [r0]
;BL IrqStart
;BL OSTimeTick
;BL IrqFinish
;LDR r0, =need_to_swap_context
LDR r2, [r0]
CMP r2, #1
LDREQ pc, =_CON_SW
_NOT_CON_SW
;not context switching
LDMIA sp!,{r0-r11, lr}
SUBS pc, lr, #4
_CON_SW
;set need_to_swap_context is '0'
MOV r1, #0
STR r1, [r0]
;now context switching
LDMIA sp!,{r0-r11,lr}
SUB lr, lr, #4
STR lr, SAVED_LR
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;Change Supervisor mode
;!!!r12 register don't preserved. (r12 that PC of task)
MRS lr, SPSR
AND lr, lr, #0xFFFFFFE0
ORR lr, lr, #0x13
MSR CPSR_cxsf, lr
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;Now Supervisor mode
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
STR r12, [sp, #-8] ; saved r12
LDR r12, SAVED_LR
STMFD sp!, {r12} ; r12 that PC of task
SUB sp, sp, #4 ; inclease stack point
LDMIA sp!, {r12} ; restore r12
STMFD sp!, {lr} ; save lr
STMFD sp!, {r0-r12} ; save register file and ret address
MRS r4, CPSR
STMFD sp!, {r4} ; save current PSR
MRS r4, SPSR ; YYY+
STMFD sp!, {r4} ; YYY+ save SPSR
; OSPrioCur = OSPrioHighRdy
LDR r4, addr_OSPrioCur
LDR r5, addr_OSPrioHighRdy
LDRB r6, [r5]
STRB r6, [r4]
; Get current task TCB address
LDR r4, addr_OSTCBCur
LDR r5, [r4]
STR sp, [r5] ; store sp in preempted tasks's TCB
; Get highest priority task TCB address
LDR r6, addr_OSTCBHighRdy
LDR r6, [r6]
LDR sp, [r6] ; get new task's stack pointer
; OSTCBCur = OSTCBHighRdy
STR r6, [r4] ; set new current task TCB address
LDMFD sp!, {r4} ; YYY+
; AND r4, r4, #0xFFFFFF20
; ORR r4, r4, #0x13
MSR SPSR_cxsf, r4 ; YYY+
LDMFD sp!, {r4} ; YYY+
; AND r4, r4, #0xFFFFFF20
; ORR r4, r4, #0x13
MSR CPSR_cxsf, r4 ; YYY+
LDMFD sp!, {r0-r12, lr, pc} ; YYY+
SAVED_LR DCD 0
; void DisableInt(void)
; void EnableInt(void)
;
; Disable and enable IRQ and FIQ preserving current CPU mode.
;
EXPORT ARMDisableInt
ARMDisableInt
STMDB sp!, {r0}
MRS r0, CPSR
ORR r0, r0, #NoInt
MSR CPSR_cxsf, r0
LDMIA sp!, {r0}
MOV pc, lr
EXPORT ARMEnableInt
ARMEnableInt
STMDB sp!, {r0}
MRS r0, CPSR
BIC r0, r0, #NoInt
MSR CPSR_cxsf, r0
LDMIA sp!, {r0}
MOV pc, lr
; void OS_TASK_SW(void)
;
; Perform a context switch.
;
; On entry, OSTCBCur and OSPrioCur hold the current TCB and priority
; and OSTCBHighRdy and OSPrioHighRdy contain the same for the task
; to be switched to.
;
; The following code assumes that the virtual memory is directly
; mapped into physical memory. If this is not true, the cache must
; be flushed at context switch to avoid address aliasing.
EXPORT OS_TASK_SW
OS_TASK_SW
STMFD sp!, {lr} ; save pc
STMFD sp!, {lr} ; save lr
STMFD sp!, {r0-r12} ; save register file and ret address
MRS r4, CPSR
STMFD sp!, {r4} ; save current PSR
MRS r4, SPSR ; YYY+
STMFD sp!, {r4} ; YYY+ save SPSR
; OSPrioCur = OSPrioHighRdy
LDR r4, addr_OSPrioCur
LDR r5, addr_OSPrioHighRdy
LDRB r6, [r5]
STRB r6, [r4]
; Get current task TCB address
LDR r4, addr_OSTCBCur
LDR r5, [r4]
STR sp, [r5] ; store sp in preempted tasks's TCB
; Get highest priority task TCB address
LDR r6, addr_OSTCBHighRdy
LDR r6, [r6]
LDR sp, [r6] ; get new task's stack pointer
; OSTCBCur = OSTCBHighRdy
STR r6, [r4] ; set new current task TCB address
LDMFD sp!, {r4} ; YYY+
MSR SPSR_cxsf, r4 ; YYY+
LDMFD sp!, {r4} ; YYY+
MSR CPSR_cxsf, r4 ; YYY+
LDMFD sp!, {r0-r12, lr, pc} ; YYY+
; void OSStartHighRdy(void)
;
; Start the task with the highest priority;
;
EXPORT OSStartHighRdy
OSStartHighRdy
LDR r4, addr_OSTCBCur ; Get current task TCB address
LDR r5, addr_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 new current task TCB address
LDMFD sp!, {r4} ; YYY
MSR SPSR_cxsf, r4
LDMFD sp!, {r4} ; get new state from top of the stack
MSR CPSR_cxsf, r4 ; CPSR should be SVC32Mode
LDMFD sp!, {r0-r12, lr, pc } ; start the new task
EXPORT OSCPUSaveSR
OSCPUSaveSR
mrs r0,CPSR
;orr r1,r0,#NOINT
msr CPSR_c,r1
mov pc,lr
EXPORT OSCPURestoreSR
OSCPURestoreSR
msr CPSR_c,r0
mov pc,lr
END
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