exp97.asm

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STACK   SEGMENT PARA STACK
        DW      100h DUP(?)
STACK   ENDS

DATA    SEGMENT PARA
LEN     EQU     121
IN_BUF  DB      LEN-1
        DB      ?
        DB      LEN DUP(?)
DATA    ENDS

CODE    SEGMENT PARA
        ASSUME  CS:CODE,DS:DATA,SS:STACK
MAIN    PROC    FAR
        MOV     AX,DATA
        MOV     DS,AX

        MOV     DX,OFFSET IN_BUF
        MOV     AH,0AH
        INT     21H

        MOV     CL,IN_BUF+1
        XOR     CH,CH
        MOV     SI,OFFSET IN_BUF+2
LP1:    MOV     AL,[SI]
        CMP     AL,'a'
        JB      L2
        CMP     AL,'z'
        JA      L2
        SUB     AL,20H
        MOV     [SI],AL
L2:     INC     SI
        LOOP    LP1

        MOV     BYTE PTR [SI],'$'

        MOV     AH,2
        MOV     DL,0DH
        INT     21H
        MOV     AH,2
        MOV     DL,0AH
        INT     21H

        MOV     DX,OFFSET IN_BUF+2
        MOV     AH,09H
        INT     21H

        MOV     AX,4C00H
        INT     21H
MAIN    ENDP
CODE    ENDS
        END     MAIN