signature TREE = 
sig 
  type label = Temp.label
  type size

datatype stm = SEQ of stm * stm
             | LABEL of label
             | JUMP of exp * label list
             | CJUMP of relop * exp * exp * label * label
	     | MOVE of exp * exp
             | EXP of exp

     and exp = BINOP of binop * exp * exp
             | MEM of exp
             | TEMP of Temp.temp
             | ESEQ of stm * exp
             | NAME of label
             | CONST of int
	     | CALL of exp * exp list

      and binop = PLUS | MINUS | MUL | DIV 
                | AND | OR | LSHIFT | RSHIFT | ARSHIFT | XOR

      and relop = EQ | NE | LT | GT | LE | GE 
	        | ULT | ULE | UGT | UGE

  val notRel : relop -> relop
(*  val commute: relop -> relop *)
end

structure Tree : TREE = 
struct
  type label=Temp.label
  type size = int



datatype stm = SEQ of stm * stm
             | LABEL of label
             | JUMP of exp * label list
             | CJUMP of relop * exp * exp * label * label
	     | MOVE of exp * exp
             | EXP of exp

     and exp = BINOP of binop * exp * exp
             | MEM of exp
             | TEMP of Temp.temp
             | ESEQ of stm * exp
             | NAME of label
             | CONST of int
	     | CALL of exp * exp list

      and binop = PLUS | MINUS | MUL | DIV 
                | AND | OR | LSHIFT | RSHIFT | ARSHIFT | XOR

      and relop = EQ | NE | LT | GT | LE | GE 
	        | ULT | ULE | UGT | UGE



(*  fun notRel (relop:Tree.relop) = *)
  fun notRel (EQ) = NE
    | notRel (NE) = EQ
    | notRel (LT) = GE
    | notRel (GT) = LE
    | notRel (LE) = GT
    | notRel (GE) = LT
    | notRel (ULT) = UGE
    | notRel (ULE) = UGT
    | notRel (UGT) = ULE
    | notRel (UGE) = ULT


(*  fun commute (relop) = EQ; *)
end