Theory JVMExec

theory JVMExec
imports JVMExecInstr JVMExceptions
(*  Title:      HOL/MicroJava/JVM/JVMExec.thy
Author: Cornelia Pusch, Gerwin Klein
Copyright 1999 Technische Universitaet Muenchen

header {* \isaheader{Program Execution in the JVM} *}

theory JVMExec imports JVMExecInstr JVMExceptions begin

exec :: "jvm_prog × jvm_state => jvm_state option"
-- "exec is not recursive. fun is just used for pattern matching"
"exec (G, xp, hp, []) = None"

| "exec (G, None, hp, (stk,loc,C,sig,pc)#frs) =
i = fst(snd(snd(snd(snd(the(method (G,C) sig)))))) ! pc;
(xcpt', hp', frs') = exec_instr i G hp stk loc C sig pc frs
in Some (find_handler G xcpt' hp' frs'))"

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

definition exec_all :: "[jvm_prog,jvm_state,jvm_state] => bool"
("_ \<turnstile> _ \<midarrow>jvm-> _" [61,61,61]60) where
"G \<turnstile> s \<midarrow>jvm-> t == (s,t) ∈ {(s,t). exec(G,s) = Some t}^*"

text {*
The start configuration of the JVM: in the start heap, we call a
method @{text m} of class @{text C} in program @{text G}. The
@{text this} pointer of the frame is set to @{text Null} to simulate
a static method invokation.

definition start_state :: "jvm_prog => cname => mname => jvm_state" where
"start_state G C m ≡
let (C',rT,mxs,mxl,i,et) = the (method (G,C) (m,[])) in
(None, start_heap G, [([], Null # replicate mxl undefined, C, (m,[]), 0)])"