INC,DEC,NEG和NOT都是单操作数指令,这个操作数应该是源操作数还是目的操作数?
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(简答题)
阅读下面的程序,回答问题 DATA SEGMENT BUF DB '1234' N=$-BUF BCD DB N DUP(?) DATA ENDS CODE SEGMENT ASSUME CS:CODE,DS:DATA START:MOV AX,DATA MOV DS,AX LEA SI,BUF MOV CX,N LEA DI,BCD+N-1 LOOP1:MOV AL,[SI] SUB AL,30H MOV [DI],AL INC SI DEC DI DEC CX JNE LOOP1 MOV AH,4CH INT 21H CODE ENDS END START 如果将代码段中的指令LEA DI,BCD+N-1改成LEA DI,BCD;DEC DI改成INC DI,其它指令不变,程序执行后,从BCD开始的N个字节单元中的内容是什么?
(简答题)
阅读下面的程序,回答问题 DATA SEGMENT BUF DB '1234' N=$-BUF BCD DB N DUP(?) DATA ENDS CODE SEGMENT ASSUME CS:CODE,DS:DATA START:MOV AX,DATA MOV DS,AX LEA SI,BUF MOV CX,N LEA DI,BCD+N-1 LOOP1:MOV AL,[SI] SUB AL,30H MOV [DI],AL INC SI DEC DI DEC CX JNE LOOP1 MOV AH,4CH INT 21H CODE ENDS END START
(简答题)
阅读下面的程序,回答问题 DATA SEGMENT BUF DB '1234' N=$-BUF BCD DB N DUP(?) DATA ENDS CODE SEGMENT ASSUME CS:CODE,DS:DATA START:MOV AX,DATA MOV DS,AX LEA SI,BUF MOV CX,N LEA DI,BCD+N-1 LOOP1:MOV AL,[SI] SUB AL,30H MOV [DI],AL INC SI DEC DI DEC CX JNE LOOP1 MOV AH,4CH INT 21H CODE ENDS END START
(简答题)
阅读下面的程序,回答问题 DATA SEGMENT BUF DB '1234' N=$-BUF BCD DB N DUP(?) DATA ENDS CODE SEGMENT ASSUME CS:CODE,DS:DATA START:MOV AX,DATA MOV DS,AX LEA SI,BUF MOV CX,N LEA DI,BCD+N-1 LOOP1:MOV AL,[SI] SUB AL,30H MOV [DI],AL INC SI DEC DI DEC CX JNE LOOP1 MOV AH,4CH INT 21H CODE ENDS END START
(简答题)
阅读下面的程序,回答问题 DATA SEGMENT BUF DB '1234' N=$-BUF BCD DB N DUP(?) DATA ENDS CODE SEGMENT ASSUME CS:CODE,DS:DATA START:MOV AX,DATA MOV DS,AX LEA SI,BUF MOV CX,N LEA DI,BCD+N-1 LOOP1:MOV AL,[SI] SUB AL,30H MOV [DI],AL INC SI DEC DI DEC CX JNE LOOP1 MOV AH,4CH INT 21H CODE ENDS END START
(简答题)
阅读下面的程序,回答问题 DATA SEGMENT BUF DB '1234' N=$-BUF BCD DB N DUP(?) DATA ENDS CODE SEGMENT ASSUME CS:CODE,DS:DATA START:MOV AX,DATA MOV DS,AX LEA SI,BUF MOV CX,N LEA DI,BCD+N-1 LOOP1:MOV AL,[SI] SUB AL,30H MOV [DI],AL INC SI DEC DI DEC CX JNE LOOP1 MOV AH,4CH INT 21H CODE ENDS END START
(简答题)
阅读下面的程序,回答问题 DATA SEGMENT BUF DB '1234' N=$-BUF BCD DB N DUP(?) DATA ENDS CODE SEGMENT ASSUME CS:CODE,DS:DATA START:MOV AX,DATA MOV DS,AX LEA SI,BUF MOV CX,N LEA DI,BCD+N-1 LOOP1:MOV AL,[SI] SUB AL,30H MOV [DI],AL INC SI DEC DI DEC CX JNE LOOP1 MOV AH,4CH INT 21H CODE ENDS END START
(简答题)
指出以下指令执行后,标志寄存器OF、SF、ZF、AF、PF、CF的状态。 (1)(AL)=0FFH,(BL)=20H,执行指令:ADD AL,BL (2)(AL)=01H, (BL)=02H,执行指令:CMP AL,BL (3)(AL)=0FFH,执行指令:INC AL (4)(AL)=0,执行指令:DEC AL (5)(AL)=0F0H,(BL)=04H,执行指令:IMUL BL (6)(AX)=1F0H,(BL)=08H,执行指令:DIV BL (7)(AL)=12H, (BL)=34H,执行指令:TEST AL,BL (8)(AL)=98H,执行指令:SAL AL,1
(简答题)
指令DEC BX和SUB BX,1的执行结果一样吗?请分析。
(判断题)
指令“INC ECX”和“ADD ECX,1”的实现功能完全一样,可以互相替换。