startup.s

arm汇编语言程序和一些实验代码

;
;	startup.s   -   first startup file for bootloader 
;
;	Author: 	li ming <[e-mail]>
;	Date:		2005-5-24
;	Copyleft:	http://www.lumit.org
;

	AREA	SelfBoot,	CODE,	READONLY

	import main
;**************************************************************************************************
; <ResetEntry> here is the very entry for the whole bootloader
	ENTRY
ResetEntry
	ldr	r0, =0x03FF5000
	ldr	r1, =0x0003FFFF		; set all 18 gpios' direction to output
	str	r1, [r0]

; here we light leds to value = "1000" to show bootloader start	
	ldr	r1, =0x00020000		; show led = 1000	
	ldr	r0, =0x03FF5008
	str	r1, [r0]
; ++++++++++++++++++++++++++++++++

	; Set up SVC stack
	mov	r0, #0xd3                ; make svc mode with all irqs disabled
	msr	cpsr_cxsf, r0		 
	mov sp, #0x80000

F_Bit		EQU 	0x40
Mode_Svc	EQU	0x13
			
	MOV	r0, #Mode_Svc:OR:F_Bit
	MSR	cpsr_c, r0
		
	b	main

;**************************************************************************************************
	END