程序框图：
开始
初始化9显示提示信息
f四、实验程序：实验程序：CRLFMACROMOVAHM02HMOVDL0DHINT21HMOVAH02HMOVDL0AHINT21HENDMDATASEGMENTMESS1DB大写转小写按10DH0AHDBDB小写转大写按20DH0AH退回DOS按30DH0AH
MESS2DB输入字符串按回车进行转换0DH0AHMARKDBBUFDB82DUPDATAENDSSTACKSEGMENTSTATOPDBEQU50DUPLENGTHSTA
STACKENDSCODESEGMENTASSUMECSCODEDSDATAESDATASSSTACKSTARTMOVAXDATAMOVDSAXMOVESAXMOVAXSTACKMOVSSAXMOVSPTOPMOVBXOFFSETBUFBX指向字符行缓冲区首址KKKMOVSI0000HMOVMARK0MOVAH09HLEADXMESS1INT21HBGMOVAH08HINT21HCMPAL3JEJEPPPBSCMPAL1CMPAL2
10
段寄存器和堆栈初始化
偏移指针SI清0
接收键入字符
fJEBSMOVLEA
SBAH09HDXMESS2大写转小写
JMPBG
INT21HMOVMARK11HBS1MOVAH01HINT21HCMPAL0DHJEBBBCMPAL5AHJATTTCMPAL41HJBTTTADDAL20HJMPTTTSBMOVLEAINTMOVSB1MOVINTJZJBJATTTAH09HDXMESS221HMARK22HAH01H21HBBBTTTTTT不是小写它母转TTT小写字母转化为大写字母存入字符行缓冲区中偏移指针加1小写转大写
CMPAL0DHCMPAL61HCMPAL7AHSUBAL20HMOVBXSIALINCSICMPMARK11HJEJEBBBBS1SB1CMPMARK22HJMPPPPMOVBXSIALMOVAL0AHMOVBXSI1ALMOVALMOVBXSI2ALMOVAH09HMOVDXBX
11
加入换行符再加一个标志字符
fINT21HJMPKKKPPPCODEMOVAX4C00HINT21HENDSENDSTART
显示转换后的字符串循环
返回DOS
12
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