chp3_20b.asm

关于8086汇编的一些作业程序

stack segment stack'stack'
      dw 32 dup(?)
stack ends
data segment
OBF1 DB 'The ASCII code of $'
OBF2 DB 'is 0DH$'
OBF3 DB 'is:',2 DUP(?),'H','$'
B DB ?
data ends
code segment 
begin proc far
      assume ss:stack,cs:code,ds:data
      push ds
      sub ax,ax
      push ax
      mov ax,data
      mov ds,ax

AGAIN:MOV DX,OFFSET OBF1
      MOV AH,9
      INT 21H
      MOV AH,1
      INT 21H
      MOV BL,AL
      CMP BL,0DH
      JE EXIT
      MOV B,BL
      AND BL,0FH
      CMP BL,0AH
      JC NADD7
      ADD BL,7
NADD7:ADD BL,30H
      MOV OBF3+4,BL
      MOV BL,B
      AND BL,0F0H
      mov cl,4
      shr bl,cl
      or bl,30h
      MOV OBF3+3,BL

      MOV DX,OFFSET OBF3
      MOV AH,9
      INT 21H
      
      MOV DL,0AH
      MOV AH,2
      INT 21H
      MOV DL,0DH
      MOV AH,2
      INT 21H
      JMP AGAIN
EXIT: MOV DX,OFFSET OBF2
      MOV AH,9
      INT 21H 
      ret 
begin endp
code ends
     end begin