📄 asm_irq.s
字号:
;------------------------------------------------------------------------------
;- ATMEL Microcontroller Software Support - ROUSSET -
;------------------------------------------------------------------------------
; The software is delivered "AS IS" without warranty or condition of any
; kind, either express, implied or statutory. This includes without
; limitation any warranty or condition with respect to merchantability or
; fitness for any particular purpose, or against the infringements of
; intellectual property rights of others.
;-----------------------------------------------------------------------------
;- File source : it_handler.s
;- Object : Example of IT handler calling a C function
;- Compilation flag : None
;-
;- 1.0 16/03/01 ODi, : Creation ARM ADS
;------------------------------------------------------------------------------
AREA itHandler, CODE, READONLY
;------------------------------------------------------------------------------
;- LISR vector handler for system peripherals
;--------------------------------------------
;- This macro save the context, call the LISR dispatch routine, and restore
;- the context
;------------------------------------------------------------------------------
INCLUDE AT91RM9200.inc
;--------------------------------
;- ARM Core Mode and Status Bits
;--------------------------------
ARM_MODE_USER EQU 0x10
ARM_MODE_FIQ EQU 0x11
ARM_MODE_IRQ EQU 0x12
ARM_MODE_SVC EQU 0x13
ARM_MODE_ABORT EQU 0x17
ARM_MODE_UNDEF EQU 0x1B
ARM_MODE_SYS EQU 0x1F
I_BIT EQU 0x80
F_BIT EQU 0x40
T_BIT EQU 0x20
NO_INT EQU 0xC0 ; Mask used to disable interrupts (Both FIR and IRQ)
SYS32_MODE EQU 0x1F
FIQ32_MODE EQU 0x11
IRQ32_MODE EQU 0x12
;------------------------------------------------------------------------------
;- IRQ Entry
;-----------
;------------------------------------------------------------------------------
MACRO
IRQ_ENTRY $reg
;- Adjust and save LR_irq in IRQ stack
sub r14, r14, #4
stmfd sp!, {r14}
;- Write in the IVR to support Protect Mode
;- No effect in Normal Mode
;- De-assert the NIRQ and clear the source in Protect Mode
ldr r14, =AT91C_BASE_AIC
str r14, [r14, #AIC_IVR]
;- Save SPSR and r0 in IRQ stack
mrs r14, SPSR
stmfd sp!, {r0, r14}
;- Enable Interrupt and Switch in SYS Mode
mrs r0, CPSR
bic r0, r0, #I_BIT
orr r0, r0, #ARM_MODE_SYS
msr CPSR_c, r0
;- Save scratch/used registers and LR in User Stack
IF "$reg" = ""
stmfd sp!, { r1-r3, r12, r14}
ELSE
stmfd sp!, { r1-r3, $reg, r12, r14}
ENDIF
MEND
;------------------------------------------------------------------------------
;- IRQ Exit
; ---------
;------------------------------------------------------------------------------
MACRO
IRQ_EXIT $reg
;- Restore scratch/used registers and LR from User Stack
IF "$reg" = ""
ldmia sp!, { r1-r3, r12, r14}
ELSE
ldmia sp!, { r1-r3, $reg, r12, r14}
ENDIF
;- Disable Interrupt and switch back in IRQ mode
mrs r0, CPSR
bic r0, r0, #ARM_MODE_SYS
orr r0, r0, #I_BIT:OR:ARM_MODE_IRQ
msr CPSR_c, r0
;- Mark the End of Interrupt on the AIC
ldr r0, =AT91C_BASE_AIC
str r0, [r0, #AIC_EOICR]
;- Restore SPSR_irq and r0 from IRQ stack
ldmia sp!, {r0, r14}
msr SPSR_cxsf, r14
;- Restore adjusted LR_irq from IRQ stack directly in the PC
ldmia sp!, {pc}^
MEND
end
;------------------------------------------------------------------------------
; AT91F_ST_ASM_HANDLER
; ---------------------
; Handler called by the AIC
;
; Save context
; Call C handler
; Restore context
;------------------------------------------------------------------------------
EXPORT AT91F_ST_ASM_HANDLER
IMPORT AT91F_ST_HANDLER
IMPORT addr_OSIntNesting
IMPORT addr_OSTCBCur
IMPORT OSIntExit
AT91F_ST_ASM_HANDLER
STR R3, [SP, #-4]! ; PUSH WORKING REGISTERS ONTO IRQ STACK
STR R2, [SP, #-4]!
STR R1, [SP, #-4]!
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 | SYS32_MODE) ; Change to SYS mode
; SAVE TASK''S CONTEXT ONTO TASK''S STACK
STR R2, [SP, #-4]! ; Push task''s Return PC
STR LR, [SP, #-4]! ; Push task''s LR
STR R12, [SP, #-4]! ; Push task''s R12-R4
STR R11, [SP, #-4]!
STR R10, [SP, #-4]!
STR R9, [SP, #-4]!
STR R8, [SP, #-4]!
STR R7, [SP, #-4]!
STR R6, [SP, #-4]!
STR R5, [SP, #-4]!
STR R4, [SP, #-4]!
LDR R4, [R1], #4 ; Move task''s R1-R3 from IRQ stack to SYS stack
LDR R5, [R1], #4
LDR R6, [R1], #4
STR R6, [SP, #-4]!
STR R5, [SP, #-4]!
STR R4, [SP, #-4]!
STR R0, [SP, #-4]! ; Push task''s R0 onto task''s stack
STR R3, [SP, #-4]! ; Push task''s CPSR (i.e. IRQ''s SPSR)
; HANDLE NESTING COUNTER
LDR R0, addr_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, addr_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 AT91F_ST_HANDLER ; OS_CPU_IRQ_ISR_Handler();
MSR CPSR_c, #(NO_INT | SYS32_MODE) ; Change to SYS mode
BL OSIntExit ; OSIntExit();
; RESTORE TASK''S CONTEXT and RETURN TO TASK
LDR R4, [SP], #4 ; pop new task''s CPSR
MSR CPSR_cxsf, R4
LDR R0, [SP], #4 ; pop new task''s context
LDR R1, [SP], #4
LDR R2, [SP], #4
LDR R3, [SP], #4
LDR R4, [SP], #4
LDR R5, [SP], #4
LDR R6, [SP], #4
LDR R7, [SP], #4
LDR R8, [SP], #4
LDR R9, [SP], #4
LDR R10, [SP], #4
LDR R11, [SP], #4
LDR R12, [SP], #4
LDR LR, [SP], #4
LDR PC, [SP], #4
end
IRQ_ENTRY
ldr r1, =AT91F_ST_HANDLER
mov r14, pc
bx r1
IRQ_EXIT
END⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -