init.s

用于在SDT环境下实现交叉环境中代码写入FLASH的过程

;; ******************************************************
;; * NAME    : SOURCE\INIT.S	     ver1.0		*
;; * C start up codes					*
;; * Fill zeros into zero-initialized C-variables	*
;; ******************************************************

;//////////// Start Area ///////////////////////

	AREA     Init, CODE, READONLY

	ENTRY

	LDR     sp, =0x100000
	LDR R0,=0x3fffff
	LDR R1,=0x3ff4008
	STR r0,[r1]			;mask all the interrupt

	B       Reset_Handler

;////////// The RESET entry point /////////

Reset_Handler

; Initialise memory required by C code

	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|	; to zero initialise

	NOP
	LDR     r0, =|Image$$RO$$Limit| ; Get pointer to ROM data
	LDR     r1, =|Image$$RW$$Base|  ; and RAM copy
	LDR     r3, =|Image$$ZI$$Base|  ; Zero init base => top of initialised
					; data
	CMP     r0, r1                  ; Check that they are different
	BEQ     %1
0	CMP     r1, r3                  ; Copy init data
	LDRCC   r2, [r0], #4
	STRCC   r2, [r1], #4
	BCC     %0
1	LDR     r1, =|Image$$ZI$$Limit| ; Top of zero init segment
	MOV     r2, #0
2	CMP     r3, r1                  ; Zero init
	STRCC   r2, [r3], #4
	BCC     %2
                    
	IMPORT    Main
	BL        Main			; Branch to C code Main routine

  	END