;文件名：TESTFILE4.S 
;功能：驗證鏈接寄存器的使用方法 
;說明：使用ARMulate軟件仿真調試 

		AREA	Example,CODE,READONLY	  	;聲明代碼段Example1 
		ENTRY				  				;標識程序入口 
		CODE32				  				;聲明32位ARM指令
		
START   LDR     R1, =SRCSTR     ; pointer to first string
        LDR     R0, =DSTSTR     ; pointer to second string

        BL      STRCOPY         ; call subroutine to do copy
        MOV		R0,#3

        B      .

STRCOPY                 
        LDRB    R2, [R1],#1     ; load byte and update address
        STRB    R2, [R0],#1     ; store byte and update address;
        CMP     R2, #0          ; check for zero terminator    0 is the end of string
        BNE     STRCOPY         ; keep going if not
        MOV     PC,LR           ; Return


        AREA    Strings, DATA, READWRITE
SRCSTR  DCB "First string - source",0
DSTSTR  DCB "Second string - destination",0

        END