(* Title: HOL/MicroJava/JVM/JVMState.thy
Author: Cornelia Pusch, Gerwin Klein, Technische Universitaet Muenchen
*)
chapter \<open>Java Virtual Machine \label{cha:jvm}\<close>
section \<open>State of the JVM\<close>
theory JVMState
imports "../J/Conform"
begin
subsection \<open>Frame Stack\<close>
type_synonym opstack = "val list"
type_synonym locvars = "val list"
type_synonym p_count = nat
type_synonym
frame = "opstack \<times>
locvars \<times>
cname \<times>
sig \<times>
p_count"
\<comment> \<open>operand stack\<close>
\<comment> \<open>local variables (including this pointer and method parameters)\<close>
\<comment> \<open>name of class where current method is defined\<close>
\<comment> \<open>method name + parameter types\<close>
\<comment> \<open>program counter within frame\<close>
subsection \<open>Exceptions\<close>
definition raise_system_xcpt :: "bool \<Rightarrow> xcpt \<Rightarrow> val option" where
"raise_system_xcpt b x \<equiv> raise_if b x None"
subsection \<open>Runtime State\<close>
type_synonym
jvm_state = "val option \<times> aheap \<times> frame list" \<comment> \<open>exception flag, heap, frames\<close>
subsection \<open>Lemmas\<close>
lemma new_Addr_OutOfMemory:
"snd (new_Addr hp) = Some xcp \<Longrightarrow> xcp = Addr (XcptRef OutOfMemory)"
proof -
obtain ref xp where "new_Addr hp = (ref, xp)" by (cases "new_Addr hp")
moreover
assume "snd (new_Addr hp) = Some xcp"
ultimately
show ?thesis by (auto dest: new_AddrD)
qed
end