单片机题目

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5,已知A=7AH,R0=30H, (30H)=A6H,PSW=81H,试问执行以下各条指令的结果.
(1)XCH A,R0 (A)=30H,R0=7AH
(2)XCH A,30H (30H)=7AH, (A)=A6H
(3)XCH A,@R0 (A)=A6H, (30H)=7AH
(4)XCHD A,@R0 (A)=76H,(30H)=AAH
(5)SWAP A (A)=A7H
(6)ADD A,R0 (A)=AAH
(7)ADD A,30H (A)=20H
(8)ADD A,#30H (A)=AAH
(9)ADDC A,30H (A)=21H
(10)SUBB A,30H (A)=D3H,CY=1
(11)SUBB A,#30H (A)=49H,CY=0
(12)DA A (A)=E0H
(13)RL A (A)=F4H
(14)RLC A (A)=F5H
(15)CJNE A,#30H,00H PC+3+00H→PC
(16)CJNE A,30H,00H PC+3+00H→PC
6,指出以下哪些指令是不存在的,并改用其他指令(或n 条指令)来实现预期的指令功能.
(1)MOV,20H,30H
(2)MOV R1,R2
(3)MOV @R3,20H
(4)MOV DPH,30H
(5)MOV C,PSW.1 (6)MOVX R2,@DPTR
(7)XCH R1,R2
解:不存在的指令有(2)(3)(6)(7) , , ,
修改:
(2)MOV A,R2 MOV R1,A
(3)MOV A,R3 MOV R0,A MOV @R0,20H
(6) MOVX A,@DPTR MOV R2, A
(7) MOV A,R1 XCH A,R2 MOV R1,A
7,设A=83H,R0=17H, (17H)=34H,问执行以下指令后,A= ?
ANL A,#17H
ORL 17H,A
XRL A,@R0
CPL A
答:执行指令后,A=CBH
老大20:14:04(11)SUBB A,#30H (A)=49H,CY=0
(12)DA A (A)=E0H
8,若SP=26H,PC=2346H,标号LABEL 所在的地址为3466 和,问执行长调用指令LCALL LABEL 后,堆栈指针和堆栈的内容发生什么变化PC 的值等于什么
答:SP+1→SP (27H)=49H SP+1→SP (28H)=23H PC 的值等于3466H
9,若已知A=76H,PSW=81H,转移指令所在地址为2080H,当执行以下指令后,程序是否发生转移PC 值等于多少
(1)JNZ 12H
(2)JNC 34H
(3)JB P,66H
(4)JBC AC,78H
(5)CJNE A,#50H,9AH
(6)DJNZ PSW,0BCH
答:
(1)转移,PC=2094H 2080+2+12
(2)不转移,PC=2082H
(3)转移,PC=20E9H
(4)不转移,PC=2083H
(5)转移,PC=211D
(6)转移,PC=213FH。