СПиОС LR_6 VAR_10

; Melnik Victor  ISPR A1
; LR_6    10 var
; Если длина симв. файла меньше N байт, то дополнить пробелами
; иначе урезать до размера N.
CODESG SEGMENT PARA 'CODE'
    ASSUME CS: CODESG, DS: CODESG, SS: CODESG, ES: CODESG
       ORG 100h
    BEGIN: JMP MAIN

        FILENAME db 'text.txt$'
        SYMBOLS db '%'

        cmd db 3 dup(0), '$'
        cmd_N dw 0

        handle dw 0
        file_len dw 0

    MAIN PROC NEAR
        CALL GET_PARAM
        mov cmd_N, bx

        ; open file RW
        mov ax, 3d02h
        lea dx, FILENAME
        int 21h
        mov handle, ax

        ; get file size
        mov ax, 4202h
        mov bx, handle
        mov cx, 0
        mov dx, 0
        int 21h
        mov file_len, ax

        ; if (file_len < cmd_N)
        mov bx, cmd_N
        cmp ax, bx
        jae @greater

        ; get count of symbols to write
        mov cx, cmd_N
        sub cx, ax
        @write_symbols:
            push cx
            mov ah, 40h
            mov cx, 1
            mov bx, handle
            lea dx, SYMBOLS
            int 21h
            pop cx
        loop @write_symbols
        jmp @close_file

      @greater: ; if (file_len > cmd_N)
        ; move pointer to cmd_N
        mov ax, 4200h
        mov bx, handle
        mov cx, 0
        mov dx, cmd_N
        int 21h
        ; write EOF
        mov ah, 40h
        mov bx, handle
        mov cx, 0
        int 21h

      @close_file:
        mov ah, 3eh
        mov bx, handle
        int 21h

        mov ah, 01h
        int 21h
        ret
    MAIN ENDP

    ; get parameters from cmd
    GET_PARAM PROC NEAR
        mov al, ds:82h
        sub al, 30h
        mov dl, al
        cbw
        mov bl, 10
        imul bl

        mov bx, ax

        mov al, ds:83h
        sub al, 30h
        js @one_symb
        cbw
        add bx, ax
        ret

      @one_symb:
        xor bx, bx
        mov bl, dl
        ret
    GET_PARAM ENDP

    CODESG ENDS
END BEGIN