Как написать программу для assembler (ассемблер)?

С выводом на экран и даже с вводом с клавиатуры.

#make_exe#
include emu8086.inc

data segment               
  a dw ?
  b dw ?
  x dw ?
  y dw ?
  z dw ?
  PromptN db 13, 10
  Prompt1 db "Введите A: ", 0
  Result db 13, 10, "Y = ", 0
  WaitMsg db 13, 10, 10, "Для завершения работы нажмите любую клавишу... ", 0
ends

stack segment
  dw 256 dup (?)
ends

code segment
N185415293:
    mov bp, data
    mov ds, bp
    lea si, Prompt1
    call print_string
    call scan_num
    mov a, cx
    inc byte ptr Prompt1 + 8
    lea si, PromptN
    call print_string
    call scan_num
    mov b, cx
    mov byte ptr Prompt1 + 8, 'X'
    lea si, PromptN
    call print_string
    call scan_num
    mov x, cx
    lea si, Result
    call print_string

    mov cx, b
    cmp cx, 10
    jge Else
    mov ax, a
    cmp ax, 3
    jle Else
    imul ax
    shl ax, 1
    add ax, cx
    add ax, cx
    add ax, cx
    dec ax
    jmp Save
   
Else:
    mov ax, x
    shl ax, 1
    inc ax
    mov z, ax
    imul ax
    sub ax, z
    sub ax, z
    sub ax, 3
    je Save
    mov ax, z
    js First
    imul ax
    dec ax
    jmp Save
First:
    add ax, 4
Save:
    mov y, ax
    call print_num

    lea si, WaitMsg
    call print_string
    mov ax, 0C01h
    int 21h
    mov ax, 4c00h
    int 21h
ends

    DEFINE_SCAN_NUM
    DEFINE_PRINT_STRING
    DEFINE_PRINT_NUM
    DEFINE_PRINT_NUM_UNS
    end N185415293

ну и ?
открываешь справочник по командам и вперед