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rt-thread-official/libcpu/arm/at91sam926x/start_rvds.S

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;/*
; * File : start_rvds.S
; * This file is part of RT-Thread RTOS
; * COPYRIGHT (C) 2006, RT-Thread Development Team
; *
; * The license and distribution terms for this file may be
; * found in the file LICENSE in this distribution or at
; * http://www.rt-thread.org/license/LICENSE
; *
; * Change Logs:
; * Date Author Notes
; * 2011-08-14 weety first version
; */
; Standard definitions of Mode bits and Interrupt (I & F) flags in PSRs
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
SVCMODE EQU 0x13
MODEMASK EQU 0x1f
I_Bit EQU 0x80 ; when I bit is set, IRQ is disabled
F_Bit EQU 0x40 ; when F bit is set, FIQ is disabled
;----------------------- Stack and Heap Definitions ----------------------------
;// <h> Stack Configuration (Stack Sizes in Bytes)
;// <o0> Undefined Mode <0x0-0xFFFFFFFF:8>
;// <o1> Supervisor Mode <0x0-0xFFFFFFFF:8>
;// <o2> Abort Mode <0x0-0xFFFFFFFF:8>
;// <o3> Fast Interrupt Mode <0x0-0xFFFFFFFF:8>
;// <o4> Interrupt Mode <0x0-0xFFFFFFFF:8>
;// <o5> User/System Mode <0x0-0xFFFFFFFF:8>
;// </h>
UND_Stack_Size EQU 512
SVC_Stack_Size EQU 4096
ABT_Stack_Size EQU 512
FIQ_Stack_Size EQU 1024
IRQ_Stack_Size EQU 1024
USR_Stack_Size EQU 512
ISR_Stack_Size EQU (UND_Stack_Size + SVC_Stack_Size + ABT_Stack_Size + \
FIQ_Stack_Size + IRQ_Stack_Size)
AREA STACK, NOINIT, READWRITE, ALIGN=3
Stack_Mem SPACE USR_Stack_Size
__initial_sp SPACE ISR_Stack_Size
Stack_Top
;// <h> Heap Configuration
;// <o> Heap Size (in Bytes) <0x0-0xFFFFFFFF>
;// </h>
Heap_Size EQU 0x00000000
AREA HEAP, NOINIT, READWRITE, ALIGN=3
__heap_base
Heap_Mem SPACE Heap_Size
__heap_limit
;----------------------- Memory Definitions ------------------------------------
AT91_MATRIX_BASE EQU 0xffffee00
AT91_MATRIX_MRCR EQU (AT91_MATRIX_BASE + 0x100)
AT91_MATRIX_RCB0 EQU 0x00000001
AT91_MATRIX_RCB1 EQU 0x00000002
AT91_AIC_BASE EQU 0xfffff000
AT91_AIC_IDCR EQU 0x124
AT91_AIC_ICCR EQU 0x128
;----------------------- CODE --------------------------------------------------
PRESERVE8
; Area Definition and Entry Point
; Startup Code must be linked first at Address at which it expects to run.
AREA RESET, CODE, READONLY
ARM
; Exception Vectors
; Mapped to Address 0.
; Absolute addressing mode must be used.
; Dummy Handlers are implemented as infinite loops which can be modified.
EXPORT Entry_Point
Entry_Point
Vectors LDR PC, Reset_Addr
LDR PC, Undef_Addr
LDR PC, SWI_Addr
LDR PC, PAbt_Addr
LDR PC, DAbt_Addr
NOP
LDR PC, IRQ_Addr
LDR PC, FIQ_Addr
Reset_Addr DCD Reset_Handler
Undef_Addr DCD Undef_Handler
SWI_Addr DCD SWI_Handler
PAbt_Addr DCD PAbt_Handler
DAbt_Addr DCD DAbt_Handler
DCD 0 ; Reserved Address
IRQ_Addr DCD IRQ_Handler
FIQ_Addr DCD FIQ_Handler
Undef_Handler B Undef_Handler
SWI_Handler B SWI_Handler
PAbt_Handler B PAbt_Handler
;DAbt_Handler B DAbt_Handler
FIQ_Handler B FIQ_Handler
;*
;*************************************************************************
;*
;* Interrupt handling
;*
;*************************************************************************
;*
; DAbt Handler
DAbt_Handler
IMPORT rt_hw_trap_dabt
sub sp, sp, #72
stmia sp, {r0 - r12} ;/* Calling r0-r12 */
add r8, sp, #60
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 OLD_R0 */
mov r0, sp
bl rt_hw_trap_dabt
;##########################################
; Reset Handler
EXPORT Reset_Handler
Reset_Handler
; set the cpu to SVC32 mode-----------------------------------------------------
MRS R0,CPSR
BIC R0,R0,#MODEMASK
ORR R0,R0,#SVCMODE
MSR CPSR_cxsf,R0
LDR R1, =AT91_AIC_BASE
LDR R0, =0xffffffff
STR R0, [R1, #AT91_AIC_IDCR]
STR R0, [R1, #AT91_AIC_ICCR]
; remap internal ram to 0x00000000 address
LDR R0, =AT91_MATRIX_MRCR
LDR R1, =(AT91_MATRIX_RCB0|AT91_MATRIX_RCB1)
STR R1, [R0]
; Copy Exception Vectors to Internal RAM ---------------------------------------
ADR R8, Vectors ; Source
LDR R9, =0x00 ; Destination
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 for each mode ----------------------------------------------------
LDR R0, =Stack_Top
; Enter Undefined Instruction Mode and set its Stack Pointer
MSR CPSR_c, #Mode_UND:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #UND_Stack_Size
; Enter Abort Mode and set its Stack Pointer
MSR CPSR_c, #Mode_ABT:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #ABT_Stack_Size
; Enter FIQ Mode and set its Stack Pointer
MSR CPSR_c, #Mode_FIQ:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #FIQ_Stack_Size
; Enter IRQ Mode and set its Stack Pointer
MSR CPSR_c, #Mode_IRQ:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #IRQ_Stack_Size
; Enter Supervisor Mode and set its Stack Pointer
MSR CPSR_c, #Mode_SVC:OR:I_Bit:OR:F_Bit
MOV SP, R0
SUB R0, R0, #SVC_Stack_Size
; Enter User Mode and set its Stack Pointer
; MSR CPSR_c, #Mode_USR
MOV SP, R0
SUB SL, SP, #USR_Stack_Size
; Enter the C code -------------------------------------------------------------
IMPORT __main
LDR R0, =__main
BX R0
IMPORT rt_interrupt_enter
IMPORT rt_interrupt_leave
IMPORT rt_thread_switch_interrput_flag
IMPORT rt_interrupt_from_thread
IMPORT rt_interrupt_to_thread
IMPORT rt_hw_trap_irq
IRQ_Handler PROC
EXPORT IRQ_Handler
STMFD sp!, {r0-r12,lr}
BL rt_interrupt_enter
BL rt_hw_trap_irq
BL rt_interrupt_leave
; if rt_thread_switch_interrput_flag set, jump to
; rt_hw_context_switch_interrupt_do and don't return
LDR r0, =rt_thread_switch_interrput_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
EXPORT rt_hw_context_switch_interrupt_do
MOV r1, #0 ; clear flag
STR r1, [r0]
LDMFD sp!, {r0-r12,lr}; reload saved registers
STMFD sp!, {r0-r3} ; save r0-r3
MOV r1, sp
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
; switch to SVC mode and no interrupt
MSR cpsr_c, #I_Bit:OR:F_Bit:OR:Mode_SVC
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]
STR sp, [r5] ; store sp in preempted tasks's TCB
LDR r6, =rt_interrupt_to_thread
LDR r6, [r6]
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 psr
MSR cpsr_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 + USR_Stack_Size)
LDR R2, = (Heap_Mem + Heap_Size)
LDR R3, = Stack_Mem
BX LR
ENDIF
END
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