第5章 课后习题答案.pdf

第 5 章 汇编语言程序设计 思考题与习题 答案 5-1:答： ORG 0 MOV R0,#30H MOV DPTR,#1000H MOV P2,#0H ; 计算机复位时(P2)=0FFH, P2决定了高8位的地址,为此须置为0 MOV R7,#20 LOOP: CLR A MOVC A,A+DPTR MOVX R0,A INC R0 INC DPTR DJNZ R7, LOOP END 5-2：答： ORG 0 MOV R7,#20 MOV R6,#20 MOV R0,#30H MOV DPTR,#1000H LOOP: MOVC A,A+DPTR MOV R0,A CLR A INC R0 INC DPTR DJNZ R7,LOOP MOV R0,#30H MOV DPTR,#2000H LOOP1:MOV A,R0 MOVX DPTR,A INC DPTR INC R0 DJNZ R6,LOOP1 END 5-3 ORG 00H X BIT 00H Y BIT 01H Z BIT 02H MOV C,X ANL C,Y MOV 03H,C CPL X MOV C,X ANL C,/Y ORL C,03H MOV Z,C END 5-4 答： ORG 00H MOV R0,#42H MOV R1,#52H MOV R7,41H LOOP2: MOV A,R0 MOV 30H,R1 CJNE A,30H,LOOP1 INC R0 INC R1 DJNZ R7,LOOP2 MOV 40H,#0H SJMP LOOP LOOP1: MOV 40H,#0FFH LOOP: NOP NOP END 5-5:答： ORG 00H X EQU 40H Y EQU 50H MOV A,X CJNE A,#0,LOOP MOV Y,#0 SJMP LOOP2 LOOP: JNB ACC.7,LOOP1 MOV Y,#0FFh SJMP LOOP2 LOOP1: MOV Y,#1 LOOP2: NOP END 5-6:答：P3.7 应该为低电平。 程序如下： ORG 00H MOV A,#0FEH CLR P3.7 MOV P0,A LOOP: LCALL DELAY1S RL A MOV P0,A SJMP LOOP DELAY1S:MOV R5,#10 DELAY0: MOV R6,#200 DELAY1: MOV R7,#250 DELAY2: DJNZ R7,DELAY2 DJNZ R6,DELAY1 DJNZ R5,DELAY0 NOP RET END 5-7:答： ORG 00H N EQU 30H MOV A, #0FEH CLR P3.7 MOV P0,A LOOP2: MOV N,#1 LOOP1: MOV R3,N LOOP: LCALL DELAY1S DJNZ R3, LOOP RL A MOV P0,A INC N MOV R4,N CJNE R4,#9,LOOP1 SJMP LOOP2 DELAY1S:MOV R5,#10 DELAY0:MOV R6,#200 DELAY1:MOV R7,#230 DELAY2:DJNZ R7,DELAY2 DJNZ R6,DELAY1 DJNZ R5,DELAY0 NOP RET END