arm45.s

用ARM编程实现两个字符串连接

	AREA X,CODE,READONLY
	EXPORT STRCAT;
STRCAT
    LDRB R2,[R0]
    ADD  R0,R0,#1
    CMP R2,#0
    BNE STRCAT
    SUB R0,R0,#1;s2中末尾0的处理
CAT   
    LDRB R3,[R1]
    CMP R3,#0
    BEQ OVER
    STRB R3,[R0]
    ADD R0,R0,#1
    ADD R1,R1,#1
    B CAT
    
    
OVER 
   STRB R3,[R0]
   MOV PC,LR
   END