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|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Part one of the system initialization code,
;; contains low-level
;; initialization.
;;
;; Copyright 2007 IAR Systems. All rights reserved.
;;
;; $Revision: 49919 $
;;
MODULE ?cstartup
;; Forward declaration of sections.
SECTION IRQ_STACK:DATA:NOROOT(3)
SECTION FIQ_STACK:DATA:NOROOT(3)
SECTION SVC_STACK:DATA:NOROOT(3)
SECTION CSTACK:DATA:NOROOT(3)
;
; The module in this file are included in the libraries, and may be
; replaced by any user-defined modules that define the PUBLIC symbol
; __iar_program_start or a user defined start symbol.
;
; To override the cstartup defined in the library, simply add your
; modified version to the workbench project.
SECTION .intvec:CODE:NOROOT(2)
PUBLIC __vector
PUBLIC __iar_program_start
EXTERN Undefined_Handler
EXTERN SWI_Handler
EXTERN Prefetch_Handler
EXTERN Abort_Handler
EXTERN IRQ_Handler
EXTERN FIQ_Handler
EXTERN LowLevelInitialisation
DATA
__iar_init$$done: ; The vector table is not needed
; until after copy initialization is done
__vector: ; Make this a DATA label, so that stack usage
; analysis doesn't consider it an uncalled fun
ARM
; All default exception handlers (except reset) are
; defined as weak symbol definitions.
; If a handler is defined by the application it will take precedence.
LDR PC,Reset_Addr ; Reset
LDR PC,Undefined_Addr ; Undefined instructions
LDR PC,SWI_Addr ; Software interrupt (SWI/SVC)
LDR PC,Prefetch_Addr ; Prefetch abort
LDR PC,Abort_Addr ; Data abort
DCD 0 ; RESERVED
LDR PC,IRQ_Addr ; IRQ
LDR PC,FIQ_Addr ; FIQ
DATA
Reset_Addr: DCD __iar_program_start
Undefined_Addr: DCD Undefined_Handler
SWI_Addr: DCD SWI_Handler
Prefetch_Addr: DCD Prefetch_Handler
Abort_Addr: DCD Abort_Handler
IRQ_Addr: DCD IRQ_Handler
FIQ_Addr: DCD FIQ_Handler
; --------------------------------------------------
; ?cstartup -- low-level system initialization code.
;
; After a reset execution starts here, the mode is ARM, supervisor
; with interrupts disabled.
;
SECTION .text:CODE:NOROOT(2)
EXTERN __cmain
REQUIRE __vector
EXTWEAK __iar_init_core
EXTWEAK __iar_init_vfp
ARM
__iar_program_start:
?cstartup:
;
; Add initialization needed before setup of stackpointers here.
;
;
; Initialize the stack pointers.
; The pattern below can be used for any of the exception stacks:
; FIQ, IRQ, SVC, ABT, UND, SYS.
; The USR mode uses the same stack as SYS.
; The stack segments must be defined in the linker command file,
; and be declared above.
;
; --------------------
; Mode, correspords to bits 0-5 in CPSR
#define MODE_MSK 0x1F ; Bit mask for mode bits in CPSR
#define USR_MODE 0x10 ; User mode
#define FIQ_MODE 0x11 ; Fast Interrupt Request mode
#define IRQ_MODE 0x12 ; Interrupt Request mode
#define SVC_MODE 0x13 ; Supervisor mode
#define ABT_MODE 0x17 ; Abort mode
#define UND_MODE 0x1B ; Undefined Instruction mode
#define SYS_MODE 0x1F ; System mode
MRS r0, cpsr ; Original PSR value
;; Set up the interrupt stack pointer.
BIC r0, r0, #MODE_MSK ; Clear the mode bits
ORR r0, r0, #IRQ_MODE ; Set IRQ mode bits
MSR cpsr_c, r0 ; Change the mode
LDR sp, =SFE(IRQ_STACK) ; End of IRQ_STACK
BIC sp,sp,#0x7 ; Make sure SP is 8 aligned
;; Set up the fast interrupt stack pointer.
BIC r0, r0, #MODE_MSK ; Clear the mode bits
ORR r0, r0, #FIQ_MODE ; Set FIR mode bits
MSR cpsr_c, r0 ; Change the mode
LDR sp, =SFE(FIQ_STACK) ; End of FIQ_STACK
BIC sp,sp,#0x7 ; Make sure SP is 8 aligned
;; Set up the normal SVC pointer.
;; FreeRTOS Note:
;; FreeRTOS does not need a System/User mode stack as only tasks run in
;; System/User mode, and their stack is allocated when the task is created.
;; Therefore the CSTACK allocated in the linker script is instead given to
;; Supervisor mode, and main() is called from Supervisor mode.
BIC r0 ,r0, #MODE_MSK ; Clear the mode bits
ORR r0 ,r0, #SVC_MODE ; Set System mode bits
MSR cpsr_c, r0 ; Change the mode
LDR sp, =SFE(CSTACK) ; End of CSTACK
BIC sp,sp,#0x7 ; Make sure SP is 8 aligned
;; Turn on core features assumed to be enabled.
FUNCALL __iar_program_start, __iar_init_core
BL __iar_init_core
;; Initialize VFP (if needed).
FUNCALL __iar_program_start, __iar_init_vfp
BL __iar_init_vfp
;; Chip and board specific configuration
BL LowLevelInitialisation
;;;
;;; Add more initialization here
;;;
;;; Continue to __cmain for C-level initialization.
FUNCALL __iar_program_start, __cmain
B __cmain
END
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