Программа для подсчета выражения

;TASM dos *.com
;собирать:
;@echo off
;tasm 111.asm
;tlink /t 111 
;del 111.map
;del 111.obj
;pause
;cls
;td 111.com
 
.model tiny
.code
org 100h
start:
push cs
pop ds
mov al, L
mul al      ;L^2
mov dx, ax
mov al, M   ;M^2
mul al
sub dx, ax  
neg dx      ;L^2-M^2
mov al, M
mul L       ;M*L
add ax, dx  ;L^2-M^2+L*M
mov Z, ax
mov ax, 4c00h
int 21h
 
L db 0
M db 4
Z dw ?
end start

format PE GUI
entry start
 
 section '.code' code readable executable
 
start:
     pop ds
mov al, [L]
mul al      ;L^2
mov dx, ax
mov al, [M]   ;M^2
mul al
sub dx, ax  
neg dx      ;L^2-M^2
mov al, [M]
mul [L]       ;M*L
add ax, dx  ;L^2-M^2+L*M
mov [Z], ax
 
   push _caption
   push _message
   push 0
  call [MessageBoxA]
  push 0
  call [ExitProcess]
  mov dx,ax
  shl dx,1
  jnc v1
  neg ax
  mov [_message],'-'
  v1: mov bx,10
  lea esi,[_message+5]
  m1: cwd
  div bx
  add [esi],dl
  dec esi
  ;cbw
cmp ax,0
jne m1
ret
 
section '.data' data readable writeable
L db 0
M db 4
Z dw ?
 
_caption db 'Win32 assembly program',0
_message db 6 dup(30h),0
 
section '.idata' import data readable writeable
 
dd 0,0,0,RVA kernel_name,RVA kernel_table
dd 0,0,0,RVA user_name,RVA user_table
dd 0,0,0,0,0
 
kernel_table:
ExitProcess dd RVA _ExitProcess
dd 0
user_table:
MessageBoxA dd RVA _MessageBoxA
dd 0
 
kernel_name db 'KERNEL32.DLL',0
user_name db 'USER32.DLL',0
 
_ExitProcess dw 0
db 'ExitProcess',0
_MessageBoxA dw 0
db 'MessageBoxA',0
 
section '.reloc' fixups data readable discardable ; needed for Win32s