Menu xu ly chuoi

; Input: string, Ouput: upper(input)
; Author: hungdh

data segment
    ; add your data here!
    MsgMenu   db 0Ah,0Dh,"Menu: $"
    Msg1   db 0Ah,0Dh,"1. Nhap chuoi.$"
    Msg2   db 0Ah,0Dh,"2. Hien thi chuoi hoa.$"
    Msg3   db 0Ah,0Dh,"3. Hien thi chuoi thuong.$"
    Msg4   db 0Ah,0Dh,"3. Hien thi chuoi dao nguoc.$"
    MsgExit   db 0Ah,0Dh,"4. Exit(E).$"
    MsgChoice db 0Ah,0Dh,"Ban chon: $"
    MsgWrong  db 0Ah,0Dh,"Nhap sai. Vui long nhap lai!$"
    MsgResult db 0Ah,0Dh,"Ket qua: $"

    strInput 100,0,100 dup('$')
ends

stack segment
    dw   128  dup(0)
ends

code segment
start:
; set segment registers:
    mov ax, data
    mov ds, ax
    mov es, ax

    ; add your code here
begin:
    MOV AH, 09h
    LEA DX, MsgMenu
    INT 21h
    LEA DX, Msg1
    INT 21h
    LEA DX, Msg2
    INT 21h
    LEA DX, Msg3
    INT 21h
    LEA DX, Msg4
    INT 21h
    LEA DX, MsgExit
    INT 21h
    LEA DX, MsgChoice
    INT 21h

    MOV AH, 01h
    INT 21h

    CMP AL, '1'
    JNZ th2
    ; Nhap chuoi
    LEA DX, strInput
    MOV AH, 0Ah
    INT 21h
    JMP begin ; Hien thi lai menu
th2:
    CMP AL, '2'
    JNZ th3
    ;Hien thi Ket qua:
    LEA DX, MsgResult
    MOV AH, 09h
    INT 21h
    ; Hien thi chu hoa
    XOR CX, CX
    LEA BX, MsgInput
    INC BX
    MOV CL, BYTE PTR [BX]
    MOV AH,02h
for1:
    INC BX
    MOV DL, BYTE PTR [BX]
    CMP DL, 'a'
    JL tiep ; Neu ki tu nhap >= a thi moi - 20
    SUB DL, 20h
tiep:
    INT 21h
    LOOP for1
    JMP begin

th3:
    CMP AL, '3'
    JNZ th4
    ;Hien thi Ket qua:
    LEA DX, MsgResult
    MOV AH, 09h
    INT 21h
    ; Hien thi chu thuong
    XOR CX, CX
    LEA BX, MsgInput
    INC BX
    MOV CL, BYTE PTR [BX]
    MOV AH,02h
for2:
    INC BX
    MOV DL, BYTE PTR [BX]
    CMP DL, 'a'
    JL tiep2 ; Neu ki tu nhap < a thi moi + 20
    ADD DL, 20h
tiep2:
    INT 21h
    LOOP for1
    JMP begin

   ; In chuoi nguoc
th4:
    CMP AL, '4'
    JNZ th5
     ;Hien thi Ket qua:
    LEA DX, MsgResult
    MOV AH, 09h
    INT 21h
    ; Hien thi chuoi nguoc
    XOR CX, CX
    LEA BX, MsgInput
    INC BX
    MOV CL, BYTE PTR [BX]
    ADD BX, CL
    MOV AH, 02h
for3:
    MOV DL, BYTE PTR [BX]
    INT 21h
    DEC BX
    LOOP for3
    JMP begin
    ; Exit
th5:
    CMP AL, '5'
    JNZ th6
    JMP thoat
th6:
    MOV AH, 09h
    LEA DX, MsgWrong
    INT 21h
    JMP begin
thoat:
    mov ax, 4c00h ; exit to operating system.
    int 21h
ends

end start ; set entry point and stop the assembler.