question on VM

[Gilles Fedak]

Hi

I am currently trying to understand how the Java VM works.
In the JVM Spec it's written that each method has memory space allocated
to hold :

 * a set of local variables referenced by a vars register,
 * an operand stack, referenced by an optop register,
 * a execution environment structure ,  referenced by a frame register

The VM Spec also notices that this memory space can be allocated at
once.

So if i well understand kaffe :
in machine.c
 * A memory space is allocated for both the local variables and the
stack.
 * optop references the stack
 * lcl references the local variables

But i don't understand the way frame is implemented and what is the
meaning of retval the parameter of the fonction virtualMachine(methods*
meth, slots* arg, slots* retval)

Thanks for all !

         ___________________________________________________________
        /   Gilles Fedak                                              
       /                                                          
      / Laboratoire de Recherche en Informatique                 
     /  universite Paris Sud                                    
    /   91405 Orsay cedex                                      
   /                                                          
  /  e-mail: mailto:fedak at lri.fr    
 /                            
/__________________________________________________________