計算機等級考試三級PC技術上機（7）

1、2013年計算機等級考試三級pc技術上機（7）請編制程序，其功能是：內存中共有30個字節(jié)型數(shù)據(jù)，找出其中的兩個ascii字符串并進行校驗。欲尋找ascii字符串由13個字符組成：#(23h)，7個ascii字符，*(2ah)，2個ascii字符，回車符(0dh)，換行符(0ah)。校驗方法為：對字符#及字符*之間的7個ascii字符進行異或操作，若異或操作結果的asccii字符表示(異或操作結果高4位的ascii字符表示在前，低4位的ascii字符表示在后)與原字符串中字符*之后的兩個ascii字符相同，則將原字符串原樣保存;反之，則將原字符串中的所有字符(共13個)均用字符!(21h)代替。

2、例如：內存中有 33h,35h,23h(#,第一個字符串開始),46h,41h,30h,2eh,34h,3dh,31h,2ah(*),32h,31h,0dh,0ah,46h,23h(#,第二個字符串開始),46h,41h,30h,2eh,34h,3dh,30h,2ah(*),32h,31h,0dh,0ah,55h結果為 23h,46h,41h,30h,2eh,34h,3dh,31h,2ah(*),32h,31h(校驗正確，該字符串原樣保持),0dh,0ah,21h,21h,21h,21h,21h,21h,21h,21h,21h,21h,21h,21h,21h(校驗錯，整個字符串用字符!代替)。

3、部分程序已給出, 其中原始數(shù)據(jù)由過程load從文件input1.dat中讀入source開始的內存單元中。運算結果要求從result開始存放,由過程save保存到文件output1.dat中。填空begin和end之間已給出的一段源程序使其完整(空白已用橫線標出,每行空白一般只需一條指令, 但采用功能相當?shù)亩鄺l指令亦可),或刪除begin和end之間原有的代碼并自行編程來完成要求的功能。對程序必須進行匯編,并與io.obj鏈接產生prog1.exe執(zhí)行文件,最終運行程序產生結果(無結果或結果不正確者均不得分)。調試中若發(fā)現(xiàn)整個程序中存在錯誤之處, 請加以修改。試題程序：extrn load:f

4、ar,save:farn equ 26stac segment stackdb 128 dup(?)stac endsdata segmentsource db n+4 dup(?)result db n dup(0)hh db 2 dup(0)name0 db input1.dat,0name1 db output1.dat,0data endscode segmentassume cs:code,ds:data,ss:stacstart proc farpush dsxor ax,axpush axmov ax,datamov ds,axlea dx,source ;數(shù)據(jù)區(qū)起始地址lea

5、si,name0 ;原始數(shù)據(jù)文件名mov cx,n+4 ;字節(jié)數(shù)call load ;從input1.dat中讀取數(shù)據(jù);*begin*mov si,0mov di,0mov bx,2 ;兩個ascii字符串repeat: mov ah,0search: mov al,sourcesiinc sicmp al,#_ searchmov resultdi,alinc disearch1:mov al,sourcesiinc sicmp al,_je asciimov resultdi,alinc dixor ah,aljmp _ascii: mov resultdi,alinc dipush di

6、mov di,0mov dh,2mov dl,ah ;異或結果暫存在dl中mov cl,4 ;先將異或結果高4位轉換成ascii字符shr ah,cl ;本行開始的4行語句將一個十六進制數(shù)轉換為ascii碼change: cmp ah,10jl add_0add ah,a-0-10add_0: add ah,0mov hhdi,ahinc didec dhjz extmov ah,dl ;再將異或結果低4位轉換成ascii字符and ah,0fhjmp changeext: pop dimov al,sourcesimov resultdi,alinc siinc dimov ah,sourc

7、esimov resultdi,ahinc siinc dimov dl,hhmov dh,hh+1cmp ax,dx_ errmov al,0dh ;校驗正確mov resultdi,alinc dimov al,0ahmov resultdi,alinc dijmp lperr: sub di,11 ;校驗錯誤mov al,!mov cx,_cover: mov resultdi,alinc diloop coverlp: _jz exitjmp repeatexit: nop;*end*lea dx,result ;結果數(shù)據(jù)區(qū)首址lea si,name1 ;結果文件名mov cx,n ;

8、字節(jié)數(shù)call save ;保存結果到文件retstart endpcode endsend startc29c91afe4ced1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6c8795ad9c91fe4ced1b6c8795ad29c91afedd1b6c87d1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6c8795ad9c91fe4ced1b6c8795ad29c91af95ad9c91afe4ced1b6c8795ad91afe4ced1b6c8795ad9d1b6c8795ad9c91afe4ced1b6c

9、8795a1afe4ced1b6c8795ad91afe4ced1b6c8795ad9c91fe4ced1b6c8795ad29c91afc91fe4ced1d1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6cd1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6c8795ad9c91fe4ced1b6c8795ad29c91af8795ad9c91fe4ced1d1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6c87d1b6c8795ad9c91afe4ced1b6c8795ad91

10、afe4ced1b6c8795ad9c91fe4ced1b6c8795ad29c91af5d1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6c8795ad9c91fe4ced1b6c8795ad29c91afad9c91fe4ced1b6c8795ad29c91afb6c8795ad29c91afb6c8795ad29c91afd1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6d1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6c8795ad9c91d1b6c8795ad9c91af

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15、ed1b6c8795ad91afe4ced1b6c8795ad9c91fe4ced1b6c8795ad29c91afad9c91fe4ced1b6c8795ad29c91afb6c8795ad29c91afb6c8795ad29c91afd1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6d1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6c8795ad9c91d1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6c8795ad9c91fe4ced1b6c8795ad29c91affe4c

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19、afe4ced1b6c8795ad9c91fe4ced1b6c8795ad29c91affe4ced1b6c8795ad29c91afc8795ad9c91fe4ced1b6c8795ad29c91afd1b6c8795ad9c91afed1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6c8d1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6c8795ad9c91fe4ced1b6c8795ad29c91af795ad9c91fe4ced1b6c8795add1b6c8795ad9c91afe4ced1b6c8795ad91afe4ced1b6c8795ad9c91fe4ced1b6c8795ad29c91af29c91af4ced1b6c8795ad1b6c8795ad9c91afe4ced1b6c8795ad91afd1b6c8795ad9c91afe4ced1b6c8795a