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rt-thread-official/libcpu/arm/arm926/start_iar.S

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ArmAsm
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;/*
; * File : start.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
; * 2011-01-13 weety first version
; */
#define S_FRAME_SIZE (18*4) ;72
;#define S_SPSR (17*4) ;SPSR
;#define S_CPSR (16*4) ;CPSR
#define S_PC (15*4) ;R15
;#define S_LR (14*4) ;R14
;#define S_SP (13*4) ;R13
;#define S_IP (12*4) ;R12
;#define S_FP (11*4) ;R11
;#define S_R10 (10*4)
;#define S_R9 (9*4)
;#define S_R8 (8*4)
;#define S_R7 (7*4)
;#define S_R6 (6*4)
;#define S_R5 (5*4)
;#define S_R4 (4*4)
;#define S_R3 (3*4)
;#define S_R2 (2*4)
;#define S_R1 (1*4)
;#define S_R0 (0*4)
#define MODE_SYS 0x1F
#define MODE_FIQ 0x11
#define MODE_IRQ 0x12
#define MODE_SVC 0x13
#define MODE_ABT 0x17
#define MODE_UND 0x1B
#define MODEMASK 0x1F
#define NOINT 0xC0
#include "rt_low_level_iar.inc"
MODULE ?cstartup
SECTION .noinit:DATA:NOROOT(3)
DATA
DS8 UND_STK_SIZE
PUBLIC UND_STACK_START
UND_STACK_START:
ALIGNRAM 2
DS8 ABT_STK_SIZE
PUBLIC ABT_STACK_START
ABT_STACK_START:
ALIGNRAM 2
DS8 FIQ_STK_SIZE
PUBLIC FIQ_STACK_START
FIQ_STACK_START:
ALIGNRAM 2
DS8 IRQ_STK_SIZE
PUBLIC IRQ_STACK_START
IRQ_STACK_START:
ALIGNRAM 2
DS8 SVC_STK_SIZE
PUBLIC SVC_STACK_START
SVC_STACK_START:
ALIGNRAM 2
DS8 SYS_STK_SIZE
PUBLIC SYS_STACK_START
SYS_STACK_START:
;--------------Jump vector table------------------------------------------------
SECTION .intvec:CODE:ROOT(2)
ARM
PUBLIC Entry_Point
Entry_Point:
__iar_init$$done: ; The interrupt vector is not needed
; until after copy initialization is done
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:
DC32 Reset_Handler
vector_undef:
DC32 Undef_Handler
vector_swi:
DC32 SWI_Handler
vector_pabt:
DC32 PAbt_Handler
vector_dabt:
DC32 DAbt_Handler
vector_resv:
DC32 Resv_Handler
vector_irq:
DC32 IRQ_Handler
vector_fiq:
DC32 FIQ_Handler
;----------------- Reset Handler -----------------------------------------------
EXTERN rt_low_level_init
EXTERN ?main
PUBLIC __iar_program_start
__iar_program_start:
Reset_Handler:
; Set the cpu to SVC32 mode
MRS R0, CPSR
BIC R0, R0, #MODEMASK
ORR R0, R0, #MODE_SVC|NOINT
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|NOINT
MSR CPSR_cxsf, R1 ; Undef mode
LDR SP, =UND_STACK_START
ORR R1,R0,#MODE_ABT|NOINT
MSR CPSR_cxsf,R1 ; Abort mode
LDR SP, =ABT_STACK_START
ORR R1,R0,#MODE_IRQ|NOINT
MSR CPSR_cxsf,R1 ; IRQ mode
LDR SP, =IRQ_STACK_START
ORR R1,R0,#MODE_FIQ|NOINT
MSR CPSR_cxsf,R1 ; FIQ mode
LDR SP, =FIQ_STACK_START
ORR R1,R0,#MODE_SYS|NOINT
MSR CPSR_cxsf,R1 ; SYS/User mode
LDR SP, =SYS_STACK_START
ORR R1,R0,#MODE_SVC|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
SECTION .text:CODE:ROOT(2)
ARM
Undef_Handler:
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
SWI_Handler:
BL rt_hw_trap_swi
PAbt_Handler:
BL rt_hw_trap_pabt
DAbt_Handler:
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
Resv_Handler:
BL rt_hw_trap_resv
IRQ_Handler:
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
FIQ_Handler:
STMFD SP!, {R0-R7,LR}
BL rt_hw_trap_fiq
LDMFD SP!, {R0-R7,LR}
SUBS PC, LR, #4
;------ void rt_hw_context_switch_interrupt_do(rt_base_t flag) -----------------
rt_hw_context_switch_interrupt_do:
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|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
END
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