cstartup_ads_bios.s

基于Atmel AT91RM9200芯片的bois。使用xmodeom协议与串口通讯。希望大家喜欢

;------------------------------------------------------------------------------
;-         ATMEL Microcontroller Software Support  -  ROUSSET  -
;------------------------------------------------------------------------------
; The software is delivered "AS IS" without warranty or condition of any
; kind, either express, implied or statutory. This includes without
; limitation any warranty or condition with respect to merchantability or
; fitness for any particular purpose, or against the infringements of
; intellectual property rights of others.
;-----------------------------------------------------------------------------
;- File source          : cstartup_boot.arm
;- Object               : Generic CStartup
;- Compilation flag     : None
;-
;- 1.0 23/10/02 	FB  : Creation ARM ADS
;------------------------------------------------------------------------------


;------------------------------------------------------------------------------
;- Area Definition
;-----------------
;- Must be defined as function to put first in the code as it must be mapped
;- at offset 0 of the flash EBI_CSR0, ie. at address 0 before remap.
;------------------------------------------------------------------------------
                AREA        reset, CODE, READONLY


;	IMPORT __use_no_semihosting_swi
;------------------------------------------------------------------------------
;- Define the entry point
;------------------------

	EXPORT	__ENTRY
__ENTRY

;Green Led
	LDR	r1, =0xFFFFF838;
	LDR	r0, =0x00000100;
	STR	r0, [r1];

;------------------------------------------------------------------------------
;- Initialise C variables
;------------------------
;- Following labels are automatically generated by the linker.
;- RO: Read-only = the code
;- RW: Read Write = the data pre-initialized and zero-initialized.
;- ZI: Zero-Initialized.
;- Pre-initialization values are located after the code area in the image.
;- Zero-initialized datas are mapped after the pre-initialized.
;- Note on the Data position :
;- If using the ARMSDT, when no -rw-base option is used for the linker, the
;- data area is mapped after the code. You can map the data either in internal
;- SRAM ( -rw-base=0x40 or 0x34) or in external SRAM ( -rw-base=0x2000000 ).
;- Note also that to improve the code density, the pre_initialized data must
;- be limited to a minimum.
;------------------------------------------------------------------------------

	add     r2, pc,#-(8+.-CInitData)  ; @ where to read values (relative)
	ldmia   r2, {r0, r1, r3, r4}

	cmp         r0, r1                  ; Check that they are different
	beq         EndRW
LoopRW
	cmp         r1, r3                  ; Copy init data
	ldrcc       r2, [r0], #4
	strcc       r2, [r1], #4
	bcc         LoopRW
EndRW

	mov         r2, #0
LoopZI
	cmp         r3, r4                  ; Zero init
	strcc       r2, [r3], #4
	bcc         LoopZI

	b           EndInitC

CInitData
	IMPORT      |Image$$RO$$Limit|      ; End of ROM code (=start of ROM data)
	IMPORT      |Image$$RW$$Base|       ; Base of RAM to initialise
	IMPORT      |Image$$ZI$$Base|       ; Base and limit of area
	IMPORT      |Image$$ZI$$Limit|      ; Top of zero init segment

	DCD     |Image$$RO$$Limit|      ; End of ROM code (=start of ROM data)
	DCD     |Image$$RW$$Base|       ; Base of RAM to initialise
 	DCD     |Image$$ZI$$Base|       ; Base and limit of area
 	DCD     |Image$$ZI$$Limit|      ; Top of zero init segment
EndInitC


;------------------------------------------------------------------------------
;- Branch on C code Main function (with interworking)
;----------------------------------------------------
;- Branch must be performed by an interworking call as either an ARM or Thumb
;- main C function must be supported. This makes the code not position-
;- independant. A Branch with link would generate errors
;------------------------------------------------------------------------------

	IMPORT      main
_main
__main
	EXPORT    _main
	EXPORT    __main
	ldr       r0, =main
	mov       lr, pc
	bx        r0

;------------------------------------------------------
; Jump to App by zlx 2005.6.3
;------------------------------------------------------
	ldr		r0, =0x20020000
	mov     lr, pc
	bx		r0	

;------------------------------------------------------------------------------
;- Loop for ever
;---------------
;- End of application. Normally, never occur.
;- Could jump on Software Reset ( B 0x0 ).
;------------------------------------------------------------------------------
End
	b           End



            END