DLL для реализации функции перемножения двух чисел без знака

AddNumbers proc stdcall a:dword, b:dword
  mov eax,a
  add eax,b
  ret
AddNumbers endp

invoke AddNumbers,1500,2200
add eax,6000

MulNumbers proc stdcall a:dword, b:dword
  mov eax,a 
  mul b
  ret
MulNumbers endp

invoke MulNumbers,150,220

funcname db "MulNumbers"
 
.code
start:
 
invoke LoadLibrary, addr libname
.IF eax != 0
  invoke GetProcAddress, eax, addr funcname
  .IF eax != 0
    mov [MulNumbers],eax
 
    push 150
    push 220
    call [MulNumbers]
 
    invoke wsprintf, addr buffer, addr format, eax
    invoke MessageBox, 0, addr buffer, addr msgta, MB_OK
  .ENDIF
.ENDIF

.386
.model flat, stdcall
option casemap:none
 
include \masm32\include\windows.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
 
.data
msgta db "Умножение", 0
buffer db 128 dup(?)
format db "%d", 0
;hLib db ?
MulNumbers dd ?
 
libname db "masmtest.dll", 0
funcname db "MulNumbers"
 
.code
start:
 
invoke LoadLibrary, addr libname
.IF eax != 0
  invoke GetProcAddress, eax, addr funcname
  .IF eax != 0
    mov [MulNumbers],eax
 
    push 150
    push 220
    call [MulNumbers]
 
 
    invoke wsprintf, addr buffer, addr format, eax
    invoke MessageBox, 0, addr buffer, addr msgta, MB_OK
  .ENDIF
.ENDIF
invoke ExitProcess, 0
end start