Theory JVMExecInstr

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



header {* \isaheader{JVM Instruction Semantics} *}


theory JVMExecInstr imports JVMInstructions JVMState begin


primrec exec_instr :: "[instr, jvm_prog, aheap, opstack, locvars, cname, sig, p_count, frame list] => jvm_state"
where
"exec_instr (Load idx) G hp stk vars Cl sig pc frs =
(None, hp, ((vars ! idx) # stk, vars, Cl, sig, pc+1)#frs)"
|

"exec_instr (Store idx) G hp stk vars Cl sig pc frs =
(None, hp, (tl stk, vars[idx:=hd stk], Cl, sig, pc+1)#frs)"
|

"exec_instr (LitPush v) G hp stk vars Cl sig pc frs =
(None, hp, (v # stk, vars, Cl, sig, pc+1)#frs)"
|

"exec_instr (New C) G hp stk vars Cl sig pc frs =
(let (oref,xp') = new_Addr hp;
fs = init_vars (fields(G,C));
hp' = if xp'=None then hp(oref \<mapsto> (C,fs)) else hp;
pc' = if xp'=None then pc+1 else pc
in
(xp', hp', (Addr oref#stk, vars, Cl, sig, pc')#frs))"
|

"exec_instr (Getfield F C) G hp stk vars Cl sig pc frs =
(let oref = hd stk;
xp' = raise_system_xcpt (oref=Null) NullPointer;
(oc,fs) = the(hp(the_Addr oref));
pc' = if xp'=None then pc+1 else pc
in
(xp', hp, (the(fs(F,C))#(tl stk), vars, Cl, sig, pc')#frs))"
|

"exec_instr (Putfield F C) G hp stk vars Cl sig pc frs =
(let (fval,oref)= (hd stk, hd(tl stk));
xp' = raise_system_xcpt (oref=Null) NullPointer;
a = the_Addr oref;
(oc,fs) = the(hp a);
hp' = if xp'=None then hp(a \<mapsto> (oc, fs((F,C) \<mapsto> fval))) else hp;
pc' = if xp'=None then pc+1 else pc
in
(xp', hp', (tl (tl stk), vars, Cl, sig, pc')#frs))"
|

"exec_instr (Checkcast C) G hp stk vars Cl sig pc frs =
(let oref = hd stk;
xp' = raise_system_xcpt (¬ cast_ok G C hp oref) ClassCast;
stk' = if xp'=None then stk else tl stk;
pc' = if xp'=None then pc+1 else pc
in
(xp', hp, (stk', vars, Cl, sig, pc')#frs))"
|

"exec_instr (Invoke C mn ps) G hp stk vars Cl sig pc frs =
(let n = length ps;
argsoref = take (n+1) stk;
oref = last argsoref;
xp' = raise_system_xcpt (oref=Null) NullPointer;
dynT = fst(the(hp(the_Addr oref)));
(dc,mh,mxs,mxl,c)= the (method (G,dynT) (mn,ps));
frs' = if xp'=None then
[([],rev argsoref@replicate mxl undefined,dc,(mn,ps),0)]
else []
in
(xp', hp, frs'@(stk, vars, Cl, sig, pc)#frs))"
|
-- "Because exception handling needs the pc of the Invoke instruction,"
-- "Invoke doesn't change stk and pc yet (@{text Return} does that)."

"exec_instr Return G hp stk0 vars Cl sig0 pc frs =
(if frs=[] then
(None, hp, [])
else
let val = hd stk0; (stk,loc,C,sig,pc) = hd frs;
(mn,pt) = sig0; n = length pt
in
(None, hp, (val#(drop (n+1) stk),loc,C,sig,pc+1)#tl frs))"

-- "Return drops arguments from the caller's stack and increases"
-- "the program counter in the caller" |

"exec_instr Pop G hp stk vars Cl sig pc frs =
(None, hp, (tl stk, vars, Cl, sig, pc+1)#frs)"
|

"exec_instr Dup G hp stk vars Cl sig pc frs =
(None, hp, (hd stk # stk, vars, Cl, sig, pc+1)#frs)"
|

"exec_instr Dup_x1 G hp stk vars Cl sig pc frs =
(None, hp, (hd stk # hd (tl stk) # hd stk # (tl (tl stk)),
vars, Cl, sig, pc+1)#frs)"
|

"exec_instr Dup_x2 G hp stk vars Cl sig pc frs =
(None, hp,
(hd stk # hd (tl stk) # (hd (tl (tl stk))) # hd stk # (tl (tl (tl stk))),
vars, Cl, sig, pc+1)#frs)"
|

"exec_instr Swap G hp stk vars Cl sig pc frs =
(let (val1,val2) = (hd stk,hd (tl stk))
in
(None, hp, (val2#val1#(tl (tl stk)), vars, Cl, sig, pc+1)#frs))"
|

"exec_instr IAdd G hp stk vars Cl sig pc frs =
(let (val1,val2) = (hd stk,hd (tl stk))
in
(None, hp, (Intg ((the_Intg val1)+(the_Intg val2))#(tl (tl stk)),
vars, Cl, sig, pc+1)#frs))"
|

"exec_instr (Ifcmpeq i) G hp stk vars Cl sig pc frs =
(let (val1,val2) = (hd stk, hd (tl stk));
pc' = if val1 = val2 then nat(int pc+i) else pc+1
in
(None, hp, (tl (tl stk), vars, Cl, sig, pc')#frs))"
|

"exec_instr (Goto i) G hp stk vars Cl sig pc frs =
(None, hp, (stk, vars, Cl, sig, nat(int pc+i))#frs)"
|

"exec_instr Throw G hp stk vars Cl sig pc frs =
(let xcpt = raise_system_xcpt (hd stk = Null) NullPointer;
xcpt' = if xcpt = None then Some (hd stk) else xcpt
in
(xcpt', hp, (stk, vars, Cl, sig, pc)#frs))"


end