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Enhancements to Tiny Language Compiler

This project introduces advanced functionalities to the Tiny language compiler, enabling features like loops, code generation, case statements, and more. The system enforces constraints, aids in code generation, and provides additional capabilities beyond the basic Tiny language.

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Enhancements to Tiny Language Compiler

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  1. repeat S1 Sn E . . . Non-simple Extensions to Tiny • The “repeat” Statement • Constrainer: E must be boolean; process S1 , … Sn • Code Generator: Cascade CurrLabel through S1, … Sn L2(CL?) S1 S2 … Sn E COND L1 L2 L1

  2. loop S1 Sn Loop-pool statement w/exit loop n=read; if (n=0)then exit else output(n); pool; exit ... Constrainer: At ’program’ node, DTEnter(LOOP_CTXT,T,T) At ‘loop’ node: -- Open_Scope; -- DTEnter(LOOP_CTXT,T,T); // LOOP_CTXT is ‘<loop_ctxt>’ -- Process kids; -- Close_scope; -- if (Decoration(T)=0) print (‘Warning: no ‘exit’) At ‘exit’ node: -- Temp = Lookup(LOOP_CTXT); -- if NodeName(Temp) <> LoopNode then Error -- Decorate(T,Temp); Decorate(Temp,T);

  3. loop S1 Sn Loop-pool statement w/exit L2(CL?) S1 S2 … Sn GOTO L2 L1 L1 loop n=read; if (n=0)then exit else output(n); pool; ... Code Generator: At ’loop’ node: -- Decorate (T, L1=Makelabel); -- Generate code (diagram); At ‘exit’ node: -- L1=Decoration(Decoration(T)); -- CodeGen1(GOTOOP, L1, Currlabel) exit GOTOL1

  4. upto <id> I F S i Pascal’s for loop (upto only) enclosing ‘for’ for i := I to F do S Constrainer: At ‘program’ node: DTEnter(FOR_CTXT, T); At ‘upto’ node: Temp = Lookup(FOR_CTXT); Decorate (T,Temp); Open_scope; DTEnter(FOR_CTXT,T); DTEnter(LOOP_CTXT); // disallows “exit” Process kids // assume <id> has correct type. while NodeName(Temp) != ProgramNode // i must be different if (NN(FK(FK(Temp)) = NN(FK(FK(T)) then Error // from lcv’s of all Temp = Decoration(Temp) // enclosing for loops Close_scope; No exit allowed

  5. upto <id> I F S i Pascal’s for loop (cont’d) enclosing ‘for’ for i := I to F do S Prohibit assignment to i Constrainer: At ‘assign’ node: Temp = Lookup(FOR_CTXT); while NodeName(Temp) != ProgramNode if (NN(FK(FK(Temp)) = NN(FK(FK(T)) then Error // x (left of assign) Temp = Decoration(Temp) // cannot match // the lcv of any // enclosing for loop

  6. upto <id> I F S i Pascal’s for loop (cont’d) for i := I to F do S CL F I ST i L1 DUP LD i BOP BGE COND L2 L3 L2 S LD i UNOP USUCC ST i GOTO L1 L3 POP 1 LIT 0 ST i CodeGenerator: Generate code (duh, see diagram) Remember: ProcessNode always returns a label return Nolabel

  7. optional case E case_clause . . . case_clause otherwise CL1 S1 CLn Sn S .. <integer> <integer> l u Case statement case v of 1..3: S1; 2: S2; otherwise S3 end; two possibilities: <integer> or Constrainer: Assume E is correct, compare with others. n

  8. optional case . . . E case_clause case_clause otherwise CL1 S1 CLn Sn S L DUP LIT n BOP BEQ CL E CL1 COND L1 L2 L1 POP 1 S1 GOTO LE L2 CL2 COND L3 L4 L3 POP 1 S2 GOTO LE Case Statement ... Ln CLn COND L2n-1 L2n L2n-1 POP 1 Sn GOTO LE L DUP DUP LIT l BOP BGE SWAP LIT u BOP BLE BOP BAND L2n POP 1 LE L2n POP 1 S LE Each CLi is one of these two OR no ‘otherwise’ ‘otherwise’

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