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rt-thread/libcpu/arm/arm926/start_rvds.S

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ArmAsm
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;/*
; * File : start_rvds.S
; * This file is part of RT-Thread RTOS
; * COPYRIGHT (C) 2006, RT-Thread Development Team
; *
; * This program is free software; you can redistribute it and/or modify
; * it under the terms of the GNU General Public License as published by
; * the Free Software Foundation; either version 2 of the License, or
; * (at your option) any later version.
; *
; * This program is distributed in the hope that it will be useful,
; * but WITHOUT ANY WARRANTY; without even the implied warranty of
; * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
; * GNU General Public License for more details.
; *
; * You should have received a copy of the GNU General Public License along
; * with this program; if not, write to the Free Software Foundation, Inc.,
; * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
; *
; * Change Logs:
; * Date Author Notes
; * 2011-08-14 weety first version
; */
; Standard definitions of Mode bits and Interrupt (I & F) flags in PSRs
S_FRAME_SIZE EQU (18*4) ;72
;S_SPSR EQU (17*4) ;SPSR
;S_CPSR EQU (16*4) ;CPSR
S_PC EQU (15*4) ;R15
;S_LR EQU (14*4) ;R14
;S_SP EQU (13*4) ;R13
;S_IP EQU (12*4) ;R12
;S_FP EQU (11*4) ;R11
;S_R10 EQU (10*4)
;S_R9 EQU (9*4)
;S_R8 EQU (8*4)
;S_R7 EQU (7*4)
;S_R6 EQU (6*4)
;S_R5 EQU (5*4)
;S_R4 EQU (4*4)
;S_R3 EQU (3*4)
;S_R2 EQU (2*4)
;S_R1 EQU (1*4)
;S_R0 EQU (0*4)
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
GET rt_low_level_keil.inc
;-------------- stack area -----------------------------------------------------
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 SVC_STK_SIZE
EXPORT SVC_STACK_START
SVC_STACK_START
ALIGN 8
SPACE SYS_STK_SIZE
EXPORT SYS_STACK_START
SYS_STACK_START
Stack_Top
Heap_Size EQU 0x00000000
AREA HEAP, NOINIT, READWRITE, ALIGN=3
__heap_base
Heap_Mem
SPACE Heap_Size
__heap_limit
;----------------------- CODE --------------------------------------------------
PRESERVE8
; Area Definition and Entry Point
; Startup Code must be linked first at Address at which it expects to run.
;--------------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
MSR CPSR_CXSF,R0
LDR SP, =SVC_STACK_START
; Call low level init function,
; disable and clear all IRQs and remap internal ram to 0x00000000.
LDR R0, =rt_low_level_init
BLX R0
; Copy Exception Vectors to Internal RAM
LDR R8, =Entry_Point ; Source
LDR R9, =0x00000000 ; Destination
CMP R8, R9
BEQ Setup_Stack
LDMIA R8!, {R0-R7} ; Load Vectors
STMIA R9!, {R0-R7} ; Store Vectors
LDMIA R8!, {R0-R7} ; Load Handler Addresses
STMIA R9!, {R0-R7} ; Store Handler Addresses
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-R3} ; Save R0-R3
MOV R1, SP ; Save old task's SP to R1
ADD SP, SP, #16 ; Restore SP
SUB R2, LR, #4 ; Save old task's PC to R2
MRS R3, 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!, {R4-R12,LR} ; Push old task's LR,R12-R4
MOV R4, R1 ; Special optimised code below
MOV R5, R3
LDMFD R4!, {R0-R3}
STMFD SP!, {R0-R3} ; Push old task's R3-R0
STMFD SP!, {R5} ; Push old task's CPSR
MRS R4, SPSR
STMFD SP!, {R4} ; Push old task's SPSR
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!, {R4} ; Pop new task's CPSR
MSR SPSR_cxsf, R4
LDMFD SP!, {R0-R12,LR,PC}^ ; pop new task's R0-R12,LR & PC
ENDP
IF :DEF:__MICROLIB
EXPORT __heap_base
EXPORT __heap_limit
ELSE
; User Initial Stack & Heap
AREA |.text|, CODE, READONLY
IMPORT __use_two_region_memory
EXPORT __user_initial_stackheap
__user_initial_stackheap
LDR R0, = Heap_Mem
LDR R1, = (Stack_Mem + SYS_STK_SIZE)
LDR R2, = (Heap_Mem + Heap_Size)
LDR R3, = Stack_Mem
BX LR
ENDIF
END
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