cstartup.s79

s3c2410 example code , it s a simple code to use s3c2410.

		EXTERN	__low_level_init
#ifdef _ECPLUSPLUS
		EXTERN	__call_ctors
#endif /*  _ECPLUSPLUS */
		EXTERN	main
		EXTERN  exit
		EXTERN	_exit

; Execution starts here.
; After a reset, the mode is ARM, Supervisor, interrupts disabled.

		LTORG

		CODE32
?cstartup

; 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.
		mrs	r0,cpsr							; Original PSR value
		bic	r0,r0,#MODE_BITS				; Clear the mode bits
		orr	r0,r0,#IRQ_MODE|NOINT					; Set IRQ mode bits
		msr	cpsr_c,r0						; Change the mode
		ldr	sp,=SFE(IRQ_STACK) & 0xFFFFFFF8	; End of IRQ_STACK
		
                ORR     r1,r0,#FIQ_MODE|NOINT
                MSR     cpsr_cxsf,r1            ;FIQMode
		ldr	sp,=SFE(FIQ_STACK) & 0xFFFFFFF8	; End of FIQ_STACK	

; Changed to the preferred mode
		bic	r0,r0,#MODE_BITS				; Clear the mode bits
		orr	r0,r0,#SVC_MODE					; Set Supervisor mode bits; enable IRQ/FIQ
		msr	cpsr_c,r0						; Change the mode
		ldr	sp,=SFE(CSTACK) & 0xFFFFFFF8	; End of CSTACK

; Change to the preferred intsruction set
#ifdef __THUMB_LIBRARY__
		adr	r0,?thumb_entry	; bit 0 is set on a Thumb code label
		bx	r0
		CODE16
		PUBLIC	?thumb_entry	; Symbol to make debuggers happy
?thumb_entry

#endif	

; Initialize segments.
; __segment_init and __low_level_init are assumed to use the same
; instruction set and to be reachable by BL from the ICODE segment
; (it is safest to link them in segment ICODE).
		bl	__low_level_init
		cmp	r0,#0
		beq	after_segment_init

		bl	__segment_init
		b	after_segment_init

		LTORG

after_segment_init:

		REQUIRE	?jump_to_main

; Call the constructors of all global objects. This code will only
; be used if any EC++ modules defines global objects that need to
; have its constructor called before main.

#ifdef _ECPLUSPLUS

		RSEG	ICODE:CODE:NOROOT(2)

		PUBLIC	?call_ctors

?call_ctors:
		LDR	R0,=SFB(DIFUNCT)		
		LDR	R1,=SFE(DIFUNCT)

		bl	__call_ctors
		b	after_call_ctors

		LTORG

after_call_ctors:

#endif /* _ECPLUSPLUS */

; Jump to main, using BX. Set _exit as the return address.
; main may be located anywhere in memory, and be of
; either ARM or Thumb mode, since BX is used.
; main is assumed to return using BX (__interwork) if it is of
; a different mode than cstartup, otherwise it will return
; in the wrong mode, causing unpredicatble behaviour.
		require _exit
		RSEG	ICODE:CODE:NOROOT(2)
		PUBLIC	__main
?jump_to_main:
		ldr	r0,=?call_exit
		mov	lr,r0		; Return address = _exit
		ldr	r0,=main
		bx	r0
__main:
?call_exit:
		ldr	r4,=_exit
		mov     lr,r4
		ldr     r4,=exit
		bx	r4

; It is not possible to fall through to _exit, because it is linked
; in a different segment.

		LTORG
		ENDMOD  ?cstartup


;-------------------------------------------------------------dl-sanl0.r79--
; ?_EXIT
; main may return an exit code in R0, or _exit may be called with
; the exit code in R0.
; If the exit code is needed for som reason, R0 should be stored 
; in e.g. one of the registers R4-R7, so that the value is 
; preserved when calling __call_dtors and _Close_all.
;---------------------------------------------------------------
		MODULE	?_EXIT
		RSEG	LIB_SEGMENT:CODE:NOROOT(SEGMENT_ALIGN)
		PUBLIC	_exit
;		EXTERN	?jump_to_exit
            	REQUIRE ?jump_to_exit

		CPU_MODE		; Either Thumb or ARM mode
_exit:
; Fall through to the next module



            	RSEG	LIB_SEGMENT:CODE:NOROOT(SEGMENT_ALIGN)
;            	EXTERN	?exit_restore
;		REQUIRE	?jump_to_exit
            	REQUIRE	?exit_restore
            	PUBLIC	?exit_save
?exit_save: 	
		MOV	R4, R0

;		ENDMOD

;---------------------------------------------------------------
; ?CALL_DTORS
; This module is only linked if needed by atexit.
;---------------------------------------------------------------
;		MODULE	?CALL_DTORS
		RSEG	LIB_SEGMENT:CODE:NOROOT(SEGMENT_ALIGN)
		PUBLIC	__cstart_call_dtors
;            	EXTERN  ?exit_save
		EXTERN	__call_dtors
		REQUIRE ?exit_save

;		CPU_MODE		; Either Thumb or ARM mode
; This label is required by "__record_needed_destruction".
__cstart_call_dtors:
		bl	__call_dtors
; Fall through to the next module
;		ENDMOD


;---------------------------------------------------------------
; ?CALL_CLOSE
; This module is only linked if needed for closing files.
;---------------------------------------------------------------
;		MODULE	?CALL_CLOSE
		RSEG	LIB_SEGMENT:CODE:NOROOT(SEGMENT_ALIGN)
		PUBLIC	__cstart_closeall
		EXTERN	_Close_all
;		EXTERN  ?exit_save
            	REQUIRE ?exit_save

		CPU_MODE		; Either Thumb or ARM mode
; This label is required by functions operating on files
__cstart_closeall:
		bl	_Close_all
; Fall through to the next module
;		ENDMOD


;---------------------------------------------------------------
; ?_EXIT_END
; Restore the argument previously stored by the "save" section
; above.
;---------------------------------------------------------------
;           	MODULE      ?_exit_end
            	RSEG        LIB_SEGMENT:CODE:NOROOT(SEGMENT_ALIGN)

            	PUBLIC      ?exit_restore
?exit_restore:
            	MOV         R0, R4

            	;; Fall through to the __exit code below

;            	ENDMOD

;---------------------------------------------------------------
; ?JUMP_TO_EXIT
;---------------------------------------------------------------
;		MODULE	?JUMP_TO_EXIT
		RSEG	LIB_SEGMENT:CODE:NOROOT(SEGMENT_ALIGN)
		PUBLIC	?jump_to_exit
		EXTERN	__exit

		CPU_MODE		; Either Thumb or ARM mode

; It is not possible to fall through to __exit, because the following 
; module is only used when linking for debugging (XLINK -r).

?jump_to_exit:	
		bl	__exit		; Thumb BL has longer reach than B
		ENDMOD


;---------------------------------------------------------------
; ?__EXIT
; __exit is declared PUBWEAK, which makes XLINK skip this module
; if another module containing a PUBLIC __exit is linked.
;---------------------------------------------------------------
		
		MODULE	?__EXIT
		RSEG	LIB_SEGMENT:CODE:NOROOT(2)
		PUBWEAK	__exit

		CPU_MODE		; Either Thumb or ARM mode
__exit

#ifdef __THUMB_LIBRARY__
		bx	pc
		nop
#endif

		CODE32		
		b	.		; Eternal loop

		ENDMOD


;---------------------------------------------------------------
; ?INITTAB
; This module is only linked if needed by e.g. __segment_init.
; The INITTAB segment contains segment initialization entries.
; See segment_init.h.
;---------------------------------------------------------------
		MODULE	?INITTAB
		RSEG	INITTAB:CONST(2)  ; Declaration for SFB/SFE below
		RSEG	HUGE_C:CONST:NOROOT(2)
		DATA
		PUBLIC	__segment_begin_INITTAB
		PUBLIC	__segment_end_INITTAB

__segment_begin_INITTAB	DC32	SFB(INITTAB)
__segment_end_INITTAB	DC32	SFE(INITTAB)

		ENDMOD


		MODULE	?ISRVECT
		RSEG	ISRVECT:DATA:NOROOT(2)
		PUBLIC  pISR_Reset, pISR_Undef, pISR_SWI, pISR_Pabort, pISR_Dabort
		PUBLIC  pISR_Reserved, pISR_IRQ, pISR_FIQ
		PUBLIC  pISR_EXT0, pISR_TIMER0, pISR_EXT2, pISR_U0TINT, pISR_U0RERR, pISR_U1TINT, pISR_U1RERR
		DATA
		
pISR_Reset 		DC32   0
pISR_Undef 		DC32   0
pISR_SWI   		DC32   0
pISR_Pabort    	DC32   0
pISR_Dabort    	DC32   0
pISR_Reserved  	DC32   0
pISR_IRQ   		DC32   0
pISR_FIQ   		DC32   0

;Don't use the label 'IntVectorTable',
;The value of IntVectorTable is different with the address you think it may be.
;IntVectorTable
pISR_EXT0  		DC32   0
pISR_EXT1  		DC32   0
pISR_EXT2  		DC32   0
pISR_EXT3 		DC32   0
pISR_U0TINT		DC32   0
pISR_U0RERR		DC32   0
pISR_U1TINT		DC32   0
pISR_U1RERR   	DC32   0
pISR_GDMA0   	DC32   0
pISR_GDMA1		DC32   0
pISR_TIMER0 	DC32   0
pISR_TIMER1 	DC32   0
pISR_HDLCTXA 	DC32   0
pISR_HDLCRXA 	DC32   0
pISR_HDLCTXB 	DC32   0
pISR_HDLCRXB	DC32   0
pISR_ECBDMATx	DC32   0
pISR_ECBDMARx	DC32   0
pISR_ECMACTx	DC32   0
pISR_ECMACRx	DC32   0
pISR_i2cbus		DC32   0

		ENDMOD
		END