(*  Title:      HOL/MicroJava/JVM/JVMExec.thy

     ID:         $Id$

     Author:     Cornelia Pusch

     Copyright   1999 Technische Universitaet Muenchen

 Execution of the JVM

 *)

 JVMExec = LoadAndStore + Object + Method + Opstack + Control + 

 datatype

  instr	= LS load_and_store	

         | CO create_object	

         | MO manipulate_object	

 	| CH check_object	

 	| MI meth_inv		

 	| MR meth_ret

 	| OS op_stack		

 	| BR branch

 types

  bytecode = instr list

  jvm_prog = "(nat \\<times> bytecode)prog"

 consts

  exec :: "jvm_prog \\<times> jvm_state \\<Rightarrow> jvm_state option"

 (** exec is not recursive. recdef is just used because for pattern matching **)

 recdef exec "{}"

  "exec (G, xp, hp, []) = None"

  "exec (G, None, hp, (stk,loc,cn,ml,pc)#frs) = 

    Some (case snd(snd(snd(the(method (G,cn) ml)))) ! pc of

       LS ins \\<Rightarrow> let (stk',loc',pc') = exec_las ins stk loc pc

 		in

 		(None,hp,(stk',loc',cn,ml,pc')#frs)

     | CO ins \\<Rightarrow> let (xp',hp',stk',pc') = exec_co ins G hp stk pc

 		in

 		(xp',hp',(stk',loc,cn,ml,pc')#frs)	    

     | MO ins \\<Rightarrow> let (xp',hp',stk',pc') = exec_mo ins hp stk pc

 		in

 		(xp',hp',(stk',loc,cn,ml,pc')#frs)

     | CH ins \\<Rightarrow> let (xp',stk',pc') = exec_ch ins G hp stk pc

 		in

 		(xp',hp,(stk',loc,cn,ml,pc')#frs)

     | MI ins \\<Rightarrow> let (xp',frs',stk',pc') = exec_mi ins G hp stk pc 

 		in

 		(xp',hp,frs'@(stk',loc,cn,ml,pc')#frs)

     | MR ins \\<Rightarrow> let frs' = exec_mr ins stk frs in (None,hp,frs')

     | OS ins \\<Rightarrow> let (stk',pc') = exec_os ins stk pc

 		in

 		(None,hp,(stk',loc,cn,ml,pc')#frs)

     | BR ins \\<Rightarrow> let (stk',pc') = exec_br ins stk pc

 		in

 		(None,hp,(stk',loc,cn,ml,pc')#frs))"

  "exec (G, Some xp, hp, f#frs) = None"

 constdefs

  exec_all :: "[jvm_prog,jvm_state,jvm_state] \\<Rightarrow> bool"  ("_ \\<turnstile> _ -jvm\\<rightarrow> _" [61,61,61]60)

  "G \\<turnstile> s -jvm\\<rightarrow> t \\<equiv> (s,t) \\<in> {(s,t). exec(G,s) = Some t}^*"

 end