汇编上机实验C-最大公约数.doc

实验C 最大公因数实验目的：从键盘输入两个不超过65535的十进制整数a、b，输出a、b的最大公因数GCD(a,b)。实验要求：键盘输入两个十进制整数a、b（其对应的二进制至多16位），以回车结束一个十进制数的输入。接着在下面的一行上输出这两个整数的最大公约数。如无最大公因数，则输出“No GCD”。注：为方便起见，最大公因数前允许有多余的前导0。实验结果：Please input two numbers and press Enter key when you want to stop a number!9600003Do you want to continue(Y/N)?yPlease input two numbers and press Enter key when you want to stop a number!301200006Do you want to continue(Y/N)?yPlease input two numbers and press Enter key when you want to stop a number!50000050Do you want to continue(Y/N)?yPlease input two numbers and press Enter key when you want to stop a number!00No GCDDo you want to continue(Y/N)?n实验报告要求:1、 分析要点及调试后的正确程序。DATAS SEGMENTUSE DB 10 DUP(0) BCNUM dw ?DCNUM dw ?DETAIL db Please input two numbers and press Enter key when you want to stop a number!,$CONTINUE db Do you want to continue(Y/N)?,$NO db No GCD,$TMP db ?DATAS ENDSEXDATAS SEGMENTFLG DB 0;标记是否为第一次计算，0是，1否EXDATAS ENDSSTACKS SEGMENT DW 100 DUP(0)STACKS ENDSCODES SEGMENT ASSUME CS:CODES,DS:DATAS,SS:STACKS,ES:EXDATASSTART:MOV AX,DATASMOV ds,AXMOV AX,EXDATASMOV ES,AX SHOWQUE:CMP FLG,0;判断是否为第一次计算JZ TWO;如果是第一次计算则跳过换行CALL CHANGELINETWO:LEA DX,DETAIL;显示提示MOV ah,9INT 21hSUB BX,BXSUB CX,CXMOV CX,10MOV SI,10ready:CALL CHANGELINESUB AX,AXSUB BX,BXSUB DX,DXINPUT:MOV ah,01h ;输入INT 21hCMP al,0dh JZ DECSITEMOV TMP,alSUB AX,AXSUB DX,DXMOV AX,BX mul CX MOV BX,AXSUB TMP,30h;转换ADD BX,word ptr TMP MOV SI,BX;保存SUB AX,AXJMP INPUT DECSITE:MOV DX,BXADD SI,2CMP SI,14JZ nextJNZ ready next:SUB AX,AXSUB BX,BXSUB CX,CXSUB DX,DX MOV AH,02hMOV DX,0dhINT 21hMOV AH,02hMOV DX,0ahINT 21h MYREADY:SUB AX,AXMOV DX,0MOV AX,BCNUMMOV CX,DCNUMCMP CX,0JZ result2DIV CXCMP DX,0JZ resultJNZ SUB1 SUB1:MOV BCNUM,CXMOV DCNUM,DXJMP MYREADYresult2:CMP AX,0JZ NOTICEMOV DX,AXJMP mycallresult:MOV DX,DX mycall:call transferMOV ah,02hINT 21h MOV ah,02hMOV DX,0dhINT 21hMOV ah,02hMOV DX,0ahINT 21h SUB AX,AXshow:MOV FLG,1LEA DX,CONTINUEMOV ah,09hINT 21hSUB AX,BXMOV ah,01hINT 21hCMP al,yJZ SHOWQUECMP al,YJZ SHOWQUEJNZ EXIT;输出转换-transfer PROC NEAR MOV SI,OFFSET USE ADD SI,4 SUB BX,CX MOV bl,$ MOV SI+1,bl MOV AX,DX MOV CX,5 AG1:MOV DX,0 MOV BX,10 DIV BX PUSH DX ADD DL,30H MOV SI,DL DEC SI POP DX LOOP AG1 MOV DX,SI INC DX MOV AH,9 INT 21H RETtransfer ENDP ;-;换行-CHANGELINE PROC NEARMOV ah,02hMOV DX,0dhINT 21hMOV ah,02hMOV DX,0ahINT 21hRETCHANGELINE ENDP;-NOTICE:LEA DX,NOMOV ah,09hINT 21hMOV ah,02hMOV DX,0dhINT 21hMOV ah,02hMOV SI,0ahINT 21h JMP showEXIT: MOV AH,4CH INT 21H CODES ENDS END START2、实验体会。这次实验并没有什么技术方面的难度，但是它难在输入数据长度的处理。如果输入了五位数，那么一个寄存器无法放下，必须增加一个寄存器，同时在进行乘法除法时，也要考虑这一点。同时有些难到我的是用户友好性的方面，为了去除一个开头显示会换行的问题，我增加了一个F