Language/OS - Multiplatform Resource Library/LANGUAGE OS.iso/sml_nj/93src.lha/src/mips/mipsinstr.sml

Text File | 1993-01-27 | 5.0 KB | 171 lines

structure MipsInstrSet =
struct

  val error = ErrorMsg.impossible

  datatype 'label info = INFO of {addrOf: 'label -> int,
                    nameOf: 'label->string}
  (*
   * satisfy ea requirements of cmachine
   *)
  abstype register = REGISTER of int
  with
       datatype register_rep = Reg' of int | Freg' of int
       fun Reg i = REGISTER i
       fun Freg i = REGISTER(i+32)
       fun reg_rep (REGISTER i) = if i<32 then Reg' i else Freg' (i-32)
       fun reg_eq(REGISTER r, REGISTER s) = r=s
  end

  datatype 'label EA = Direct of register
            | Immed of int
             | ImmedLab of 'label

  val baseReg   = Reg 24
  val limitReg  = Reg 19
  val heapExhaustedReg = Reg 21
  val maskReg = Reg 25
  val allocReg  = Reg 23
  val exnptrReg = Reg 30
  val linkReg   = Reg 31

  datatype 'label sdi
    = SETBASEADDR of 'label * register
    | LOADADDR    of register * 'label * int
    | LOAD        of register * 'label * int
    | LOADF       of register * 'label * int * register
    | BRANCH      of bool * register * register * 'label * register * 'label
    | BRANCH_COP1 of bool * 'label * register * 'label

  val constBaseRegOffset = 32764

 (* satisfy operand requirements of mips instruction set.
  * memOpnd should require no more than 16 bits when computed.
  *)
  datatype 'label signedlabel = POSLAB of 'label | NEGLAB of 'label
  type 'label labexp = 'label signedlabel * int
  datatype 'label arithOpnd = Immed16Op of int
                     | RegOp of register
                     | LabelOp of 'label labexp
                     | HiLabOp of 'label labexp
                     | LoLabOp of 'label labexp

  datatype 'label memOpnd = Immed16Off of int
              | LabOff of 'label labexp
              | HiLabOff of 'label labexp
                 | LoLabOff of 'label labexp

  datatype int5      = Int5 of int

  fun split i = let val hi = Bits.rshift(i,16)
            val lo = Bits.andb(i,65535)
        in
            if lo < 32768 then (hi,lo) else (hi+1, lo-65536)
        end

  fun chk_immed16 n =  let
    exception Immed16
      in  if n>= ~32768 andalso n<=65535 then n
      else (app System.Print.say
          ["Immed16 constant too large ", makestring n, "\n"];
        raise Immed16)
      end

  fun labelValue (INFO{addrOf,...}) (POSLAB lab,k) = k + addrOf lab
    | labelValue (INFO{addrOf,...}) (NEGLAB lab,k) = k - addrOf lab

  fun hiLabelValue info labexp = #1 (split (labelValue info labexp))
  fun loLabelValue info labexp = #2 (split (labelValue info labexp))

  fun labBranchOff info (LabOff labexp) = let
    exception BranchOffset
    val labOff = labelValue info labexp
      in
      if labOff rem 4 <> 0 then raise BranchOffset
      else labOff div 4
      end
    | labBranchOff _ _ = error "MipsInstrSet.labBranchOff: bad label"

  datatype 'label instruction
    = NOP

   (*
    * compare instructions:
    *)
    | SLT      of register * register * 'label arithOpnd
    | SLTU     of register * register * 'label arithOpnd
    | SLT_DOUBLE  of register * register
    | SEQ_DOUBLE  of register * register

   (*
    * branch instructions.
    * This list is incomplete as the other branch instructions
    * are all span dependent.
    *)
    | JUMP     of register
    | BLTZAL    of unit
    | BEQ           of bool * register * register * 'label memOpnd
    | BCOP1       of bool * 'label memOpnd


   (*
    * Arithmetic instructions:
    * arguments are (rd,rs,rt/immed) with the exception of sub (sigh).
    *)
    | ADD     of register * register * 'label arithOpnd
    | ADDU    of register * register * 'label arithOpnd
    | AND     of register * register * 'label arithOpnd
    | OR     of register * register * 'label arithOpnd
    | XOR     of register * register * 'label arithOpnd
    | SUB     of register * register * register

    (*
     * integer mult and div related:
     *)
    | MULT     of register * register
    | DIV     of register * register
    | MFLO     of register
    | MFHI     of register
    | BREAK    of int

   (*
    * Floating point arithmetic:
    *)
    | NEG_DOUBLE  of register * register
    | ABS_DOUBLE  of register * register
    | MUL_DOUBLE  of register * register * register
    | DIV_DOUBLE  of register * register * register
    | ADD_DOUBLE  of register * register * register
    | SUB_DOUBLE  of register * register * register
    | CVTI2D      of register * register
    | MTC1      of register * register

   (*
    * Move pseudo-instruction :  move(dst,src)
    *)
    | MOV_DOUBLE  of register * register

   (* Load and store instructions:
    * arguments are: op(rd, base(offset))
    *)
    | LBU      of register * register * 'label memOpnd
    | SB      of register * register * 'label memOpnd
    | LW      of register * register * 'label memOpnd
    | SW     of register * register * 'label memOpnd
    | LWC1    of register * register * 'label memOpnd
    | SWC1    of register * register * 'label memOpnd
    | LUI     of register * 'label memOpnd

   (*
    * Shift instructions:
    * arguments are: (rd,rs,shamt)
    *)
    | SLL of register * register * int5
    | SLLV of register * register * register
    | SRA of register * register * int5
    | SRAV of register * register * register
end