start_rvds.S
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;/*
; * Copyright (c) 2006-2018, RT-Thread Development Team
; *
; * SPDX-License-Identifier: Apache-2.0
; *
; * Change Logs:
; * Date Author Notes
; * 2011-08-14 weety first version
; * 2015-04-15 ArdaFu Split from AT91SAM9260 BSP
; * 2015-04-21 ArdaFu Remove remap code. Using mmu to map vector table
; * 2015-06-04 aozima Align stack address to 8 byte.
; */
UND_STK_SIZE EQU 512
SVC_STK_SIZE EQU 4096
ABT_STK_SIZE EQU 512
IRQ_STK_SIZE EQU 1024
FIQ_STK_SIZE EQU 1024
SYS_STK_SIZE EQU 512
Heap_Size EQU 512
S_FRAME_SIZE EQU (18*4) ;72
S_PC EQU (15*4) ;R15
MODE_USR EQU 0X10
MODE_FIQ EQU 0X11
MODE_IRQ EQU 0X12
MODE_SVC EQU 0X13
MODE_ABT EQU 0X17
MODE_UND EQU 0X1B
MODE_SYS EQU 0X1F
MODEMASK EQU 0X1F
NOINT EQU 0xC0
;----------------------- Stack and Heap Definitions ----------------------------
AREA STACK, NOINIT, READWRITE, ALIGN=3
Stack_Mem
SPACE UND_STK_SIZE
EXPORT UND_STACK_START
UND_STACK_START
ALIGN 8
SPACE ABT_STK_SIZE
EXPORT ABT_STACK_START
ABT_STACK_START
ALIGN 8
SPACE FIQ_STK_SIZE
EXPORT FIQ_STACK_START
FIQ_STACK_START
ALIGN 8
SPACE IRQ_STK_SIZE
EXPORT IRQ_STACK_START
IRQ_STACK_START
ALIGN 8
SPACE SYS_STK_SIZE
EXPORT SYS_STACK_START
SYS_STACK_START
ALIGN 8
SPACE SVC_STK_SIZE
EXPORT SVC_STACK_START
SVC_STACK_START
Stack_Top
__initial_sp
__heap_base
Heap_Mem SPACE Heap_Size
__heap_limit
PRESERVE8
;--------------Jump vector table------------------------------------------------
EXPORT Entry_Point
AREA RESET, CODE, READONLY
ARM
Entry_Point
LDR PC, vector_reset
LDR PC, vector_undef
LDR PC, vector_swi
LDR PC, vector_pabt
LDR PC, vector_dabt
LDR PC, vector_resv
LDR PC, vector_irq
LDR PC, vector_fiq
vector_reset
DCD Reset_Handler
vector_undef
DCD Undef_Handler
vector_swi
DCD SWI_Handler
vector_pabt
DCD PAbt_Handler
vector_dabt
DCD DAbt_Handler
vector_resv
DCD Resv_Handler
vector_irq
DCD IRQ_Handler
vector_fiq
DCD FIQ_Handler
;----------------- Reset Handler -----------------------------------------------
IMPORT rt_low_level_init
IMPORT __main
EXPORT Reset_Handler
Reset_Handler
; set the cpu to SVC32 mode
MRS R0,CPSR
BIC R0,R0,#MODEMASK
ORR R0,R0,#MODE_SVC:OR:NOINT
MSR CPSR_cxsf,R0
; Set CO-Processor
; little-end，disbale I/D Cache MMU, vector table is 0x00000000
MRC p15, 0, R0, c1, c0, 0 ; Read CP15
LDR R1, =0x00003085 ; set clear bits
BIC R0, R0, R1
MCR p15, 0, R0, c1, c0, 0 ; Write CP15
; Call low level init function,
; disable and clear all IRQs, Init MMU, Init interrupt controller, etc.
LDR SP, =SVC_STACK_START
LDR R0, =rt_low_level_init
BLX R0
Setup_Stack
; Setup Stack for each mode
MRS R0, CPSR
BIC R0, R0, #MODEMASK
ORR R1, R0, #MODE_UND:OR:NOINT
MSR CPSR_cxsf, R1 ; Undef mode
LDR SP, =UND_STACK_START
ORR R1,R0,#MODE_ABT:OR:NOINT
MSR CPSR_cxsf,R1 ; Abort mode
LDR SP, =ABT_STACK_START
ORR R1,R0,#MODE_IRQ:OR:NOINT
MSR CPSR_cxsf,R1 ; IRQ mode
LDR SP, =IRQ_STACK_START
ORR R1,R0,#MODE_FIQ:OR:NOINT
MSR CPSR_cxsf,R1 ; FIQ mode
LDR SP, =FIQ_STACK_START
ORR R1,R0,#MODE_SYS:OR:NOINT
MSR CPSR_cxsf,R1 ; SYS/User mode
LDR SP, =SYS_STACK_START
ORR R1,R0,#MODE_SVC:OR:NOINT
MSR CPSR_cxsf,R1 ; SVC mode
LDR SP, =SVC_STACK_START
; Enter the C code
LDR R0, =__main
BLX R0
;----------------- Exception Handler -------------------------------------------
IMPORT rt_hw_trap_udef
IMPORT rt_hw_trap_swi
IMPORT rt_hw_trap_pabt
IMPORT rt_hw_trap_dabt
IMPORT rt_hw_trap_resv
IMPORT rt_hw_trap_irq
IMPORT rt_hw_trap_fiq
IMPORT rt_interrupt_enter
IMPORT rt_interrupt_leave
IMPORT rt_thread_switch_interrupt_flag
IMPORT rt_interrupt_from_thread
IMPORT rt_interrupt_to_thread
Undef_Handler PROC
SUB SP, SP, #S_FRAME_SIZE
STMIA SP, {R0 - R12} ; Calling R0-R12
ADD R8, SP, #S_PC
STMDB R8, {SP, LR} ; Calling SP, LR
STR LR, [R8, #0] ; Save calling PC
MRS R6, SPSR
STR R6, [R8, #4] ; Save CPSR
STR R0, [R8, #8] ; Save SPSR
MOV R0, SP
BL rt_hw_trap_udef
ENDP
SWI_Handler PROC
BL rt_hw_trap_swi
ENDP
PAbt_Handler PROC
BL rt_hw_trap_pabt
ENDP
DAbt_Handler PROC
SUB SP, SP, #S_FRAME_SIZE
STMIA SP, {R0 - R12} ; Calling R0-R12
ADD R8, SP, #S_PC
STMDB R8, {SP, LR} ; Calling SP, LR
STR LR, [R8, #0] ; Save calling PC
MRS R6, SPSR
STR R6, [R8, #4] ; Save CPSR
STR R0, [R8, #8] ; Save SPSR
MOV R0, SP
BL rt_hw_trap_dabt
ENDP
Resv_Handler PROC
BL rt_hw_trap_resv
ENDP
FIQ_Handler PROC
STMFD SP!, {R0-R7,LR}
BL rt_hw_trap_fiq
LDMFD SP!, {R0-R7,LR}
SUBS PC, LR, #4
ENDP
IRQ_Handler PROC
STMFD SP!, {R0-R12,LR}
BL rt_interrupt_enter
BL rt_hw_trap_irq
BL rt_interrupt_leave
; If rt_thread_switch_interrupt_flag set,
; jump to rt_hw_context_switch_interrupt_do and don't return
LDR R0, =rt_thread_switch_interrupt_flag
LDR R1, [R0]
CMP R1, #1
BEQ rt_hw_context_switch_interrupt_do
LDMFD SP!, {R0-R12,LR}
SUBS PC, LR, #4
ENDP
;------ void rt_hw_context_switch_interrupt_do(rt_base_t flag) -----------------
rt_hw_context_switch_interrupt_do PROC
MOV R1, #0 ; Clear flag
STR R1, [R0] ; Save to flag variable
LDMFD SP!, {R0-R12,LR} ; Reload saved registers
STMFD SP, {R0-R2} ; Save R0-R2
SUB R1, SP, #4*3 ; Save old task's SP to R1
SUB R2, LR, #4 ; Save old task's PC to R2
MRS R0, SPSR ; Get CPSR of interrupt thread
MSR CPSR_c, #MODE_SVC:OR:NOINT ; Switch to SVC mode and no interrupt
STMFD SP!, {R2} ; Push old task's PC
STMFD SP!, {R3-R12,LR} ; Push old task's LR,R12-R3
LDMFD R1, {R1-R3}
STMFD SP!, {R1-R3} ; Push old task's R2-R0
STMFD SP!, {R0} ; Push old task's CPSR
LDR R4, =rt_interrupt_from_thread
LDR R5, [R4] ; R5 = stack ptr in old tasks's TCB
STR SP, [R5] ; Store SP in preempted tasks's TCB
LDR R6, =rt_interrupt_to_thread
LDR R6, [R6] ; R6 = stack ptr in new tasks's TCB
LDR SP, [R6] ; Get new task's stack pointer
LDMFD SP!, {R4} ; Pop new task's SPSR
MSR SPSR_cxsf, R4
LDMFD SP!, {R0-R12,LR,PC}^ ; pop new task's R0-R12,LR & PC SPSR to CPSR
ENDP
;*******************************************************************************
; User Stack and Heap initialization
;*******************************************************************************
IF :DEF:__MICROLIB
EXPORT __initial_sp
EXPORT __heap_base
EXPORT __heap_limit
ELSE
IMPORT __use_two_region_memory
EXPORT __user_initial_stackheap
__user_initial_stackheap
LDR R0, = Heap_Mem ; heap base
LDR R1, = SVC_STACK_START ; stack base (top-address)
LDR R2, = (Heap_Mem + Heap_Size) ; heap limit
LDR R3, = (SVC_STACK_START - SVC_STK_SIZE) ; stack limit (low-address)
BX LR
ALIGN
ENDIF
END