(* Title: HOL/MicroJava/JVM/Opstack.thy
ID: $Id$
Author: Cornelia Pusch
Copyright 1999 Technische Universitaet Muenchen
Manipulation of operand stack
*)
Opstack = JVMState +
(** instructions for the direct manipulation of the operand stack **)
datatype
op_stack =
Pop
| Dup
| Dup_x1
| Dup_x2
| Swap
| ADD
consts
exec_os :: "[op_stack,opstack,p_count] \\<Rightarrow> (opstack \\<times> p_count)"
primrec
"exec_os Pop stk pc = (tl stk , pc+1)"
"exec_os Dup stk pc = (hd stk # stk , pc+1)"
"exec_os Dup_x1 stk pc = (hd stk # hd (tl stk) # hd stk # (tl (tl stk)) , pc+1)"
"exec_os Dup_x2 stk pc = (hd stk # hd (tl stk) # (hd (tl (tl stk))) # hd stk # (tl (tl (tl stk))) , pc+1)"
"exec_os Swap stk pc =
(let (val1,val2) = (hd stk,hd (tl stk))
in
(val2#val1#(tl (tl stk)) , pc+1))"
"exec_os ADD stk pc =
(let (val1,val2) = (hd stk,hd (tl stk))
in
(Intg ((the_Intg val1)+(the_Intg val2))#(tl (tl stk)), pc+1))"
end