.model SMALL
.stack 100h

input_buff_size EQU 1024
output_buff_size EQU 1024

.data
  input_file DB "duom.txt", 0
  output_file DB "rez.txt", 0
  input_buff DB input_buff_size dup (?)
  output_buff DB output_buff_size dup (?)
  enteris DB 10, 13, "$"

  error_read DB "Klaida atidarant duomenu faila", 10, 13, "$"
  error_write DB "Klaida atidarant rezultatu faila", 10, 13, "$"
  error_reading DB "Klaida skaitant duomenu faila", 10, 13, "$"
  error_writing DB "Klaida rasant i rezultatu faila", 10, 13, "$"
  incomplete_writing DB "Nevisi duomenys surasyti i rezultatu faila", 10, 13, "$"
  error_closing DB "Nepavyko uzdaryti failo", 10, 13, "$"

  zero DB "nulis", 10, 13, "$"
  one DB "vienas", 10, 13, "$"
  two DB "du", 10, 13, "$"
  three DB "trys", 10, 13, "$"
  four DB "keturi", 10, 13, "$"
  five DB "penki", 10, 13, "$"
  six DB "sesi", 10, 13, "$"
  seven DB "septyni", 10, 13, "$"
  eight DB "astuoni", 10, 13, "$"
  nine DB "devyni", 10, 13, "$"

  input_handle DW ?
  output_handle DW ?

.code
pradzia:
  MOV AX, @data
  MOV DS, AX

  CALL open_input_file
  CALL open_output_file

  read:
    MOV BX, input_handle
    CALL read_input_file
    CMP AX, 0
    JE close_output_file

  ; darbas su nuskaityta info
  MOV CX, AX
  PUSH AX
  LEA SI, input_buff
  LEA DI, output_buff

  LEA BX, zero
  ; tikrinam ar current symbol == '0'
  lyginimas:
    XOR AX, AX
    MOV DL, [SI]
    CMP DL, '0'
    JE write_zero
    JNE tesinys ; tesk jeigu nera 0
    write_zero:
      MOV DX, [BX]
      MOV [DI], DX
      INC DI
      INC BX
      INC AX
      CMP AL, 5
      JLE write_zero
      JNE tesinys

  tesinys:
    INC SI
    LOOP lyginimas

  ; rezultatu irasymas
  POP AX
  MOV CX, AX
  MOV BX, output_handle
  CALL output_buffer
  CMP AX, input_buff_size
  JE read

  JMP pabaiga

close_output_file:
  MOV AH, 3Eh
  MOV BX, output_handle
  INT 21h
  JC error_closing_file
  JMP pabaiga

close_input_file:
  MOV AH, 3Eh
  MOV BX, input_handle
  INT 21h
  JC error_closing_file
  JMP pabaiga


; ***** klaidos *****
error_opening_read:
  MOV AH, 9
  LEA DX, error_read
  INT 21h
  JMP pabaiga
error_opening_write:
  MOV AH, 9
  LEA DX, error_write
  INT 21h
  JMP pabaiga
error_closing_file:
  MOV AH, 9
  LEA DX, error_closing
  INT 21h
  JMP pabaiga


PROC open_input_file
  MOV AH, 3Dh
  MOV AL, 00
  LEA DX, input_file
  INT 21h
  JC error_opening_read
  MOV input_handle, AX
  RET
open_input_file ENDP

PROC open_output_file
  MOV AH, 3Ch
  MOV CX, 0
  LEA DX, output_file
  INT 21h
  JC error_opening_write
  MOV output_handle, AX
  RET
open_output_file ENDP

PROC read_input_file
  PUSH CX
  PUSH DX

  MOV AH, 3Fh
  MOV CX, input_buff_size
  LEA DX, input_buff
  INT 21h
  JC error_while_reading

  read_input_file_end:
    POP DX
    POP CX
    RET

  error_while_reading:
    MOV AX, 0
    MOV AH, 9
    LEA DX, error_reading
    INT 21h
    JMP read_input_file_end
read_input_file ENDP

PROC output_buffer
  PUSH DX

  MOV AH, 40h
  LEA DX, output_buff
  INT 21h
  JC error_while_writing
  CMP CX, AX
  JNE incomplete_write

  incomplete_write:
    MOV AH, 9
    LEA DX, incomplete_writing
    INT 21h
    JMP write_output_end

  write_output_end:
    POP DX
    RET

  error_while_writing:
    MOV AX, 0
    MOV AH, 9
    LEA DX, error_writing
    INT 21h
    JMP write_output_end
output_buffer ENDP

pabaiga:
  MOV AH, 4Ch
  MOV AL, 0
  INT 21h
END pradzia