MCS-51单片机应用子程序：4.2 ASCII码到十六进制数的转换

ASCTOHEX: MOV R0,#41H CLR C MOV A,R0 CJNE A,#30H,LOOP0 LOOP0: JC C,LOOP4 CJNE A,#47H,LOOP2 LOOP2: JNC C,LOOP4 CLR C MOV A,R1 SUBB A,#30H MOV R0,A SUBB A,#0AH JC C,LOOP3 XCH A,R0 SUBB A,#07H MOV R0,A LOOP3: RET LOOP4: MOV R0,#0FFH RET