boot.s

用philips lpc2312+DSP实现MP3播放

;-------------------------------------------------------------------------------------------------------------
;Cread by zhangyi @2006-1-3 10:25上午
;V1.0
;-------------------------------------------------------------------------------------------------------------

Mode_USR        EQU     0x10
Mode_FIQ        EQU     0x11
Mode_IRQ        EQU     0x12
Mode_SVC        EQU     0x13
Mode_ABT        EQU     0x17
Mode_UND        EQU     0x1B
Mode_SYS        EQU     0x1F ;available on ARM Arch 4 and later

DISIRQ			EQU		0x80
DISFIQ			EQU		0x40

UNDSTACKLEN		EQU		0*4
SVCSTACKLEN		EQU		0*4
ABTSTACKLEN		EQU		0*4
FIQSTACKLEN		EQU		0*4
IRQSTACKLEN		EQU		32*4
SYSSTACKLEN		EQU		256*4

RAMTOP			EQU		0x40004000
SYSSTACKADD		EQU		RAMTOP
IRQSTACKADD		EQU		(SYSSTACKADD-SYSSTACKLEN)
FIQSTACKADD		EQU		(IRQSTACKADD-IRQSTACKLEN)
ABTSTACKADD		EQU		(FIQSTACKADD-FIQSTACKLEN)
SVCSTACKADD		EQU		(ABTSTACKADD-ABTSTACKLEN)
UNDSTACKADD		EQU		(SVCSTACKADD-SVCSTACKLEN)


	IMPORT	__main
	
	EXPORT	__user_initial_stackheap
	EXPORT	UseStacks

	AREA	armboot,CODE,READONLY
	CODE32
	ENTRY
	B	Reset
	B	Undefine
	B	SWI_Pro
	B	Pre_Pro
	B	Abt_Pro
	DCD	0xb9205f80
	LDR	PC,[PC,#-0xff0]
FIQ
	B	FIQ
Undefine
	B	Undefine
Pre_Pro
	B	Pre_Pro
Abt_Pro
	B	Abt_Pro
SWI_Pro
	B	SWI_Pro		;User add
Reset
	MSR	CPSR_c,		#Mode_UND:OR:DISIRQ:OR:DISFIQ
	LDR	SP,=UNDSTACKADD
	
	MSR	CPSR_c,		#Mode_SVC:OR:DISIRQ:OR:DISFIQ
	LDR	SP,=SVCSTACKADD
	
	MSR	CPSR_c,		#Mode_ABT:OR:DISIRQ:OR:DISFIQ
	LDR	SP,=ABTSTACKADD
	
	MSR	CPSR_c,		#Mode_FIQ:OR:DISIRQ:OR:DISFIQ
	LDR	SP,=FIQSTACKADD
	
	MSR	CPSR_c,		#Mode_IRQ:OR:DISIRQ:OR:DISFIQ
	LDR	SP,=IRQSTACKADD
	
	MSR	CPSR_c,		#Mode_SYS:OR:DISFIQ		;enable irq
	LDR	SP,=SYSSTACKADD
	
	B	__main
	
__user_initial_stackheap
	LDR	R0,=bottomheap
	LDR	R1,=UseStacks
	MOV	PC,LR

	AREA	Heap,DATA,NOINIT
bottomheap	SPACE	1

	AREA	Stacks,DATA,NOINIT
UseStacks	SPACE	1
	end