fpc/compiler/m68k/cgcpu.pas

{
    Copyright (c) 1998-2002 by the FPC team

    This unit implements the code generator for the 680x0

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 ****************************************************************************
}
{DEFINE DEBUG_CHARLIE}

{$IFNDEF DEBUG_CHARLIE}
{$WARNINGS OFF}
{$ENDIF}
unit cgcpu;

{$i fpcdefs.inc}

  interface

    uses
       cgbase,cgobj,globtype,
       aasmbase,aasmtai,aasmdata,aasmcpu,
       cpubase,cpuinfo,
       parabase,cpupara,
       node,symconst,symtype,symdef,
       cgutils,cg64f32;

    type
      tcg68k = class(tcg)
        procedure init_register_allocators;override;
        procedure done_register_allocators;override;

        procedure a_load_reg_cgpara(list : TAsmList;size : tcgsize;r : tregister;const cgpara : tcgpara);override;
        procedure a_load_const_cgpara(list : TAsmList;size : tcgsize;a : tcgint;const cgpara : tcgpara);override;
        procedure a_load_ref_cgpara(list : TAsmList;size : tcgsize;const r : treference;const cgpara : tcgpara);override;
        procedure a_loadaddr_ref_cgpara(list : TAsmList;const r : treference;const cgpara : tcgpara);override;

        procedure a_call_name(list : TAsmList;const s : string; weak: boolean);override;
        procedure a_call_reg(list : TAsmList;reg : tregister);override;

        procedure a_load_const_reg(list : TAsmList;size : tcgsize;a : tcgint;register : tregister);override;
        procedure a_load_const_ref(list : TAsmList; tosize: tcgsize; a : tcgint;const ref : treference);override;

        procedure a_load_reg_ref(list : TAsmList;fromsize,tosize : tcgsize;register : tregister;const ref : treference);override;
        procedure a_load_reg_reg(list : TAsmList;fromsize,tosize : tcgsize;reg1,reg2 : tregister);override;
        procedure a_load_ref_reg(list : TAsmList;fromsize,tosize : tcgsize;const ref : treference;register : tregister);override;
        procedure a_load_ref_ref(list : TAsmList;fromsize,tosize : tcgsize;const sref : treference;const dref : treference);override;

        procedure a_loadaddr_ref_reg(list : TAsmList;const ref : treference;r : tregister);override;
        procedure a_loadfpu_reg_reg(list: TAsmList; fromsize, tosize: tcgsize; reg1, reg2: tregister); override;
        procedure a_loadfpu_ref_reg(list: TAsmList; fromsize, tosize: tcgsize; const ref: treference; reg: tregister); override;
        procedure a_loadfpu_reg_ref(list: TAsmList; fromsize, tosize: tcgsize; reg: tregister; const ref: treference); override;

        procedure a_loadmm_reg_reg(list: TAsmList;fromsize,tosize : tcgsize; reg1, reg2: tregister;shuffle : pmmshuffle); override;
        procedure a_loadmm_ref_reg(list: TAsmList;fromsize,tosize : tcgsize; const ref: treference; reg: tregister;shuffle : pmmshuffle); override;
        procedure a_loadmm_reg_ref(list: TAsmList;fromsize,tosize : tcgsize; reg: tregister; const ref: treference;shuffle : pmmshuffle); override;
        procedure a_loadmm_reg_cgpara(list: TAsmList; size: tcgsize; reg: tregister;const locpara : TCGPara;shuffle : pmmshuffle); override;

        procedure a_op_const_reg(list : TAsmList; Op: TOpCG; size: tcgsize; a: tcgint; reg: TRegister); override;
//        procedure a_op_const_ref(list : TAsmList; Op: TOpCG; size: TCGSize; a: tcgint; const ref: TReference); override;
        procedure a_op_reg_reg(list : TAsmList; Op: TOpCG; size: TCGSize; reg1, reg2: TRegister); override;

        procedure a_cmp_const_reg_label(list : TAsmList;size : tcgsize;cmp_op : topcmp;a : tcgint;reg : tregister;
          l : tasmlabel);override;
        procedure a_cmp_reg_reg_label(list : TAsmList;size : tcgsize;cmp_op : topcmp;reg1,reg2 : tregister;l : tasmlabel); override;
        procedure a_jmp_name(list : TAsmList;const s : string); override;
        procedure a_jmp_always(list : TAsmList;l: tasmlabel); override;
        procedure a_jmp_flags(list : TAsmList;const f : TResFlags;l: tasmlabel); override;
        procedure g_flags2reg(list: TAsmList; size: TCgSize; const f: tresflags; reg: TRegister); override;

        procedure g_concatcopy(list : TAsmList;const source,dest : treference;len : tcgint);override;
        { generates overflow checking code for a node }
        procedure g_overflowcheck(list: TAsmList; const l:tlocation; def:tdef); override;

        procedure g_proc_entry(list : TAsmList;localsize : longint;nostackframe:boolean);override;
        procedure g_proc_exit(list : TAsmList;parasize:longint;nostackframe:boolean);override;

//        procedure g_restore_frame_pointer(list : TAsmList);override;
//        procedure g_return_from_proc(list : TAsmList;parasize : tcgint);override;
        procedure g_restore_registers(list:TAsmList);override;
        procedure g_save_registers(list:TAsmList);override;

//        procedure g_save_all_registers(list : TAsmList);override;
//        procedure g_restore_all_registers(list : TAsmList;const funcretparaloc:TCGPara);override;

        procedure g_intf_wrapper(list: TAsmList; procdef: tprocdef; const labelname: string; ioffset: longint);override;

     protected
        function fixref(list: TAsmList; var ref: treference): boolean;
     private
        { # Sign or zero extend the register to a full 32-bit value.
            The new value is left in the same register.
        }
        procedure sign_extend(list: TAsmList;_oldsize : tcgsize; reg: tregister);
        procedure a_jmp_cond(list : TAsmList;cond : TOpCmp;l: tasmlabel);

     end;

     tcg64f68k = class(tcg64f32)
       procedure a_op64_reg_reg(list : TAsmList;op:TOpCG; size: tcgsize; regsrc,regdst : tregister64);override;
       procedure a_op64_const_reg(list : TAsmList;op:TOpCG; size: tcgsize; value : int64;regdst : tregister64);override;
     end;

     { This function returns true if the reference+offset is valid.
       Otherwise extra code must be generated to solve the reference.

       On the m68k, this verifies that the reference is valid
       (e.g : if index register is used, then the max displacement
        is 256 bytes, if only base is used, then max displacement
        is 32K
     }
     function isvalidrefoffset(const ref: treference): boolean;

    const
      TCGSize2OpSize: Array[tcgsize] of topsize =
        (S_NO,S_B,S_W,S_L,S_L,S_NO,S_B,S_W,S_L,S_L,S_NO,
         S_FS,S_FD,S_FX,S_NO,S_NO,
         S_NO,S_NO,S_NO,S_NO,S_NO,S_NO,
         S_NO,S_NO,S_NO,S_NO,S_NO,S_NO);

    procedure create_codegen;

  implementation

    uses
       globals,verbose,systems,cutils,
       symsym,defutil,paramgr,procinfo,
       rgobj,tgobj,rgcpu,fmodule;


    const
      { opcode table lookup }
      topcg2tasmop: Array[topcg] of tasmop =
      (
       A_NONE,
       A_MOVE,
       A_ADD,
       A_AND,
       A_DIVU,
       A_DIVS,
       A_MULS,
       A_MULU,
       A_NEG,
       A_NOT,
       A_OR,
       A_ASR,
       A_LSL,
       A_LSR,
       A_SUB,
       A_EOR,
       A_NONE,
       A_NONE
      );


      TOpCmp2AsmCond: Array[topcmp] of TAsmCond =
      (
       C_NONE,
       C_EQ,
       C_GT,
       C_LT,
       C_GE,
       C_LE,
       C_NE,
       C_LS,
       C_CS,
       C_CC,
       C_HI
      );


     function isvalidrefoffset(const ref: treference): boolean;
      begin
         isvalidrefoffset := true;
         if ref.index <> NR_NO then
           begin
             if ref.base <> NR_NO then
                internalerror(2002081401);
             if (ref.offset < low(shortint)) or (ref.offset > high(shortint)) then
                isvalidrefoffset := false
           end
         else
           begin
             if (ref.offset < low(smallint)) or (ref.offset > high(smallint)) then
                isvalidrefoffset := false;
           end;
      end;


{****************************************************************************}
{                               TCG68K                                       }
{****************************************************************************}


    function use_push(const cgpara:tcgpara):boolean;
      begin
        result:=(not paramanager.use_fixed_stack) and
                assigned(cgpara.location) and
                (cgpara.location^.loc=LOC_REFERENCE) and
                (cgpara.location^.reference.index=NR_STACK_POINTER_REG);
      end;


    procedure tcg68k.init_register_allocators;
      begin
        inherited init_register_allocators;
        rg[R_INTREGISTER]:=trgcpu.create(R_INTREGISTER,R_SUBWHOLE,
          [RS_D0,RS_D1,RS_D2,RS_D3,RS_D4,RS_D5,RS_D6,RS_D7],
          first_int_imreg,[]);
        rg[R_ADDRESSREGISTER]:=trgcpu.create(R_ADDRESSREGISTER,R_SUBWHOLE,
          [RS_A0,RS_A1,RS_A2,RS_A3,RS_A4,RS_A5,RS_A6],
          first_addr_imreg,[]);
        rg[R_FPUREGISTER]:=trgcpu.create(R_FPUREGISTER,R_SUBNONE,
          [RS_FP0,RS_FP1,RS_FP2,RS_FP3,RS_FP4,RS_FP5,RS_FP6,RS_FP7],
          first_fpu_imreg,[]);
      end;


    procedure tcg68k.done_register_allocators;
      begin
        rg[R_INTREGISTER].free;
        rg[R_FPUREGISTER].free;
        rg[R_ADDRESSREGISTER].free;
        inherited done_register_allocators;
      end;


    procedure tcg68k.a_load_reg_cgpara(list : TAsmList;size : tcgsize;r : tregister;const cgpara : tcgpara);
      var
        pushsize : tcgsize;
        ref : treference;
      begin
{$ifdef DEBUG_CHARLIE}
//        writeln('a_load_reg');_cgpara
{$endif DEBUG_CHARLIE}
        { it's probably necessary to port this from x86 later, or provide an m68k solution (KB) }
{ TODO: FIX ME! check_register_size()}
        // check_register_size(size,r);
        if use_push(cgpara) then
          begin
            cgpara.check_simple_location;
            if tcgsize2size[cgpara.location^.size]>cgpara.alignment then
              pushsize:=cgpara.location^.size
            else
              pushsize:=int_cgsize(cgpara.alignment);

            reference_reset_base(ref, NR_STACK_POINTER_REG, 0, cgpara.alignment);
            ref.direction := dir_dec;
            list.concat(taicpu.op_reg_ref(A_MOVE,tcgsize2opsize[pushsize],makeregsize(list,r,pushsize),ref));
          end
        else
          inherited a_load_reg_cgpara(list,size,r,cgpara);
      end;


    procedure tcg68k.a_load_const_cgpara(list : TAsmList;size : tcgsize;a : tcgint;const cgpara : tcgpara);
      var
        pushsize : tcgsize;
        ref : treference;
      begin
{$ifdef DEBUG_CHARLIE}
//        writeln('a_load_const');_cgpara
{$endif DEBUG_CHARLIE}
        if use_push(cgpara) then
          begin
            cgpara.check_simple_location;
            if tcgsize2size[cgpara.location^.size]>cgpara.alignment then
              pushsize:=cgpara.location^.size
            else
              pushsize:=int_cgsize(cgpara.alignment);

            reference_reset_base(ref, NR_STACK_POINTER_REG, 0, cgpara.alignment);
            ref.direction := dir_dec;
            list.concat(taicpu.op_const_ref(A_MOVE,tcgsize2opsize[pushsize],a,ref));
          end
        else
          inherited a_load_const_cgpara(list,size,a,cgpara);
      end;


    procedure tcg68k.a_load_ref_cgpara(list : TAsmList;size : tcgsize;const r : treference;const cgpara : tcgpara);

        procedure pushdata(paraloc:pcgparalocation;ofs:tcgint);
        var
          pushsize : tcgsize;
          tmpreg   : tregister;
          href     : treference;
          ref      : treference;
        begin
          if not assigned(paraloc) then
            exit;
{ TODO: FIX ME!!! this also triggers location bug }
          {if (paraloc^.loc<>LOC_REFERENCE) or
             (paraloc^.reference.index<>NR_STACK_POINTER_REG) or
             (tcgsize2size[paraloc^.size]>sizeof(tcgint)) then
            internalerror(200501162);}

          { Pushes are needed in reverse order, add the size of the
            current location to the offset where to load from. This
            prevents wrong calculations for the last location when
            the size is not a power of 2 }
          if assigned(paraloc^.next) then
            pushdata(paraloc^.next,ofs+tcgsize2size[paraloc^.size]);
          { Push the data starting at ofs }
          href:=r;
          inc(href.offset,ofs);
          fixref(list,href);
          if tcgsize2size[paraloc^.size]>cgpara.alignment then
            pushsize:=paraloc^.size
          else
            pushsize:=int_cgsize(cgpara.alignment);

          reference_reset_base(ref, NR_STACK_POINTER_REG, 0, tcgsize2size[paraloc^.size]);
          ref.direction := dir_dec;

          if tcgsize2size[paraloc^.size]<cgpara.alignment then
            begin
              tmpreg:=getintregister(list,pushsize);
              a_load_ref_reg(list,paraloc^.size,pushsize,href,tmpreg);
              list.concat(taicpu.op_reg_ref(A_MOVE,tcgsize2opsize[pushsize],tmpreg,ref));
            end
          else
              list.concat(taicpu.op_ref_ref(A_MOVE,tcgsize2opsize[pushsize],href,ref));
        end;

      var
        len : tcgint;
        href : treference;
      begin
{$ifdef DEBUG_CHARLIE}
//        writeln('a_load_ref');_cgpara
{$endif DEBUG_CHARLIE}

        { cgpara.size=OS_NO requires a copy on the stack }
        if use_push(cgpara) then
          begin
            { Record copy? }
            if (cgpara.size in [OS_NO,OS_F64]) or (size=OS_NO) then
              begin
                cgpara.check_simple_location;
                len:=align(cgpara.intsize,cgpara.alignment);
                g_stackpointer_alloc(list,len);
                reference_reset_base(href,NR_STACK_POINTER_REG,0,cgpara.alignment);
                g_concatcopy(list,r,href,len);
              end
            else
              begin
                if tcgsize2size[cgpara.size]<>tcgsize2size[size] then
                  internalerror(200501161);
                { We need to push the data in reverse order,
                  therefor we use a recursive algorithm }
                pushdata(cgpara.location,0);
              end
          end
        else
          inherited a_load_ref_cgpara(list,size,r,cgpara);
      end;


    procedure tcg68k.a_loadaddr_ref_cgpara(list : TAsmList;const r : treference;const cgpara : tcgpara);
      var
        tmpreg : tregister;
        opsize : topsize;
      begin
{$ifdef DEBUG_CHARLIE}
//        writeln('a_loadaddr_ref');_cgpara
{$endif DEBUG_CHARLIE}
        with r do
          begin
            { i suppose this is not required for m68k (KB) }
//            if (segment<>NR_NO) then
//              cgmessage(cg_e_cant_use_far_pointer_there);
            if not use_push(cgpara) then
              begin
                cgpara.check_simple_location;
                opsize:=tcgsize2opsize[OS_ADDR];
                if (segment=NR_NO) and (base=NR_NO) and (index=NR_NO) then
                  begin
                    if assigned(symbol) then
//                      list.concat(Taicpu.Op_sym_ofs(A_PUSH,opsize,symbol,offset))
                    else;
//                      list.concat(Taicpu.Op_const(A_PUSH,opsize,offset));
                  end
                else if (segment=NR_NO) and (base=NR_NO) and (index<>NR_NO) and
                        (offset=0) and (scalefactor=0) and (symbol=nil) then
//                  list.concat(Taicpu.Op_reg(A_PUSH,opsize,index))
                else if (segment=NR_NO) and (base<>NR_NO) and (index=NR_NO) and
                        (offset=0) and (symbol=nil) then
//                  list.concat(Taicpu.Op_reg(A_PUSH,opsize,base))
                else
                  begin
                    tmpreg:=getaddressregister(list);
                    a_loadaddr_ref_reg(list,r,tmpreg);
//                    list.concat(taicpu.op_reg(A_PUSH,opsize,tmpreg));
                  end;
              end
            else
              inherited a_loadaddr_ref_cgpara(list,r,cgpara);
          end;
      end;



    function tcg68k.fixref(list: TAsmList; var ref: treference): boolean;
       var
         hreg,idxreg : tregister;
         href : treference;
       begin
         result:=false;
         { The MC68020+ has extended
           addressing capabilities with a 32-bit
           displacement.
         }
         if (current_settings.cputype=cpu_MC68020) then
           exit;
         { ToDo: check which constraints of Coldfire also apply to MC68000 }
         case current_settings.cputype of
           cpu_MC68000:
             begin
               if (ref.base<>NR_NO) then
                 begin
                   if (ref.index <> NR_NO) and assigned(ref.symbol) then
                      internalerror(2002081402);
                   { base + reg }
                   if ref.index <> NR_NO then
                      begin
                         { base + reg + offset }
                         if (ref.offset < low(shortint)) or (ref.offset > high(shortint)) then
                           begin
                              list.concat(taicpu.op_const_reg(A_ADD,S_L,ref.offset,ref.base));
                              fixref := true;
                              ref.offset := 0;
                              exit;
                           end;
                      end
                   else
                   { base + offset }
                   if (ref.offset < low(smallint)) or (ref.offset > high(smallint)) then
                     begin
                       list.concat(taicpu.op_const_reg(A_ADD,S_L,ref.offset,ref.base));
                       fixref := true;
                       ref.offset := 0;
                       exit;
                     end;
                 end;
             end;
           cpu_Coldfire:
             begin
               if (ref.base<>NR_NO) then
                 begin
                   if assigned(ref.symbol) and (ref.index=NR_NO) then
                     begin
                       hreg:=cg.getaddressregister(list);
                       reference_reset_symbol(href,ref.symbol,0,ref.alignment);
                       list.concat(taicpu.op_ref_reg(A_LEA,S_L,href,hreg));
                       ref.index:=ref.base;
                       ref.base:=hreg;
                       ref.symbol:=nil;
                     end;
                   if (ref.index<>NR_NO) and assigned(ref.symbol) then
                     begin
                       list.concat(taicpu.op_reg_reg(A_ADD,S_L,ref.base,ref.index));
                       ref.index:=NR_NO;
                     end;
                   {if (ref.index <> NR_NO) and assigned(ref.symbol) then
                      internalerror(2002081403);}
                   { first ensure that base is an address register }
                   if not isaddressregister(ref.base) then
                     begin
                       hreg:=getaddressregister(list);
                       list.concat(taicpu.op_reg_reg(A_MOVE,S_L,ref.base,hreg));
                       fixref:=true;
                       ref.base:=hreg;
                     end;
                   { base + reg }
                   if ref.index <> NR_NO then
                      begin
                         { base + reg + offset }
                         if (ref.offset < low(shortint)) or (ref.offset > high(shortint)) then
                           begin
                              list.concat(taicpu.op_const_reg(A_ADD,S_L,ref.offset,ref.base));
                              fixref := true;
                              ref.offset := 0;
                              exit;
                           end;
                      end
                   else
                   { base + offset }
                   if (ref.offset < low(smallint)) or (ref.offset > high(smallint)) then
                     begin
                       list.concat(taicpu.op_const_reg(A_ADD,S_L,ref.offset,ref.base));
                       fixref:=true;
                       ref.offset:=0;
                       exit;
                     end;
                 end
               else
                 { Note: symbol -> ref would be supported as long as ref does not
                         contain a offset or index... (maybe something for the
                         optimizer) }
                 if Assigned(ref.symbol) {and (ref.index<>NR_NO)} then
                   begin
                     hreg:=cg.getaddressregister(list);
                     idxreg:=ref.index;
                     ref.index:=NR_NO;
                     list.concat(taicpu.op_ref_reg(A_LEA,S_L,ref,hreg));
                     reference_reset_base(ref,hreg,0,ref.alignment);
                     ref.index:=idxreg;
                     fixref:=true;
                   end;
             end;
         end;
       end;



    procedure tcg68k.a_call_name(list : TAsmList;const s : string; weak: boolean);
      var
        sym: tasmsymbol;
      begin
        if not(weak) then
          sym:=current_asmdata.RefAsmSymbol(s)
        else
          sym:=current_asmdata.WeakRefAsmSymbol(s);

        list.concat(taicpu.op_sym(A_JSR,S_NO,current_asmdata.RefAsmSymbol(s)));
      end;


    procedure tcg68k.a_call_reg(list : TAsmList;reg: tregister);
      var
        tmpref : treference;
	tmpreg : tregister;
      begin
{$ifdef DEBUG_CHARLIE}
	list.concat(tai_comment.create(strpnew('a_call_reg')));
{$endif}
	if isaddressregister(reg) then
	  begin
	    { if we have an address register, we can jump to the address directly }
            reference_reset_base(tmpref,reg,0,4);
	  end
	else
	  begin
	    { if we have a data register, we need to move it to an address register first }
	    tmpreg:=getaddressregister(list);
            reference_reset_base(tmpref,tmpreg,0,4);
	    list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg,tmpreg));
	  end;
	list.concat(taicpu.op_ref(A_JSR,S_NO,tmpref));
     end;



    procedure tcg68k.a_load_const_reg(list : TAsmList;size : tcgsize;a : tcgint;register : tregister);
      begin
{$ifdef DEBUG_CHARLIE}
//        writeln('a_load_const_reg');
{$endif DEBUG_CHARLIE}

        if isaddressregister(register) then
         begin
           list.concat(taicpu.op_const_reg(A_MOVE,S_L,longint(a),register))
         end
        else
        if a = 0 then
           list.concat(taicpu.op_reg(A_CLR,S_L,register))
        else
         begin
           if (longint(a) >= low(shortint)) and (longint(a) <= high(shortint)) then
              list.concat(taicpu.op_const_reg(A_MOVEQ,S_L,longint(a),register))
           else
              list.concat(taicpu.op_const_reg(A_MOVE,S_L,longint(a),register))
         end;
      end;

    procedure tcg68k.a_load_const_ref(list : TAsmList; tosize: tcgsize; a : tcgint;const ref : treference);
      var
        hreg : tregister;
        href : treference;
      begin
{$ifdef DEBUG_CHARLIE}
        list.concat(tai_comment.create(strpnew('a_load_const_ref')));
{$endif DEBUG_CHARLIE}

        href:=ref;
        fixref(list,href);
        { for coldfire we need to go through a temporary register if we have a
          offset, index or symbol given }
        if (current_settings.cputype=cpu_coldfire) and
            (
              (href.offset<>0) or
              { TODO : check whether we really need this second condition }
              (href.index<>NR_NO) or
              assigned(href.symbol)
            ) then
          begin
            hreg:=getintregister(list,tosize);
            list.concat(taicpu.op_const_reg(A_MOVE,S_L,longint(a),hreg));
            list.concat(taicpu.op_reg_ref(A_MOVE,S_L,hreg,href));
          end
        else
          list.concat(taicpu.op_const_ref(A_MOVE,S_L,longint(a),href));
      end;


    procedure tcg68k.a_load_reg_ref(list : TAsmList;fromsize,tosize : tcgsize;register : tregister;const ref : treference);
      var
       href : treference;
      begin
        href := ref;
        fixref(list,href);
{$ifdef DEBUG_CHARLIE}
        list.concat(tai_comment.create(strpnew('a_load_reg_ref')));
{$endif DEBUG_CHARLIE}
        { move to destination reference }
        list.concat(taicpu.op_reg_ref(A_MOVE,TCGSize2OpSize[fromsize],register,href));
      end;


    procedure tcg68k.a_load_ref_ref(list : TAsmList;fromsize,tosize : tcgsize;const sref : treference;const dref : treference);
      var
        aref: treference;
        bref: treference;
        dofix : boolean;
        hreg: TRegister;
      begin
        aref := sref;
        bref := dref;
        fixref(list,aref);
        fixref(list,bref);
{$ifdef DEBUG_CHARLIE}
//        writeln('a_load_ref_ref');
{$endif DEBUG_CHARLIE}
        { Coldfire dislikes certain move combinations }
        if current_settings.cputype=cpu_coldfire then
          begin
            { TODO : move.b/w only allowed in newer coldfires... (ISA_B+) }

            dofix:=false;
            if { (d16,Ax) and (d8,Ax,Xi) }
                (
                  (aref.base<>NR_NO) and
                  (
                    (aref.index<>NR_NO) or
                    (aref.offset<>0)
                  )
                ) or
                { (xxx) }
                assigned(aref.symbol) then
              begin
                if aref.index<>NR_NO then
                  begin
                    dofix:={ (d16,Ax) and (d8,Ax,Xi) }
                           (
                             (bref.base<>NR_NO) and
                             (
                               (bref.index<>NR_NO) or
                               (bref.offset<>0)
                             )
                           ) or
                           { (xxx) }
                           assigned(bref.symbol);
                  end
                else
                  { offset <> 0, but no index }
                  begin
                    dofix:={ (d8,Ax,Xi) }
                           (
                             (bref.base<>NR_NO) and
                             (bref.index<>NR_NO)
                           ) or
                           { (xxx) }
                           assigned(bref.symbol);
                  end;
              end;

            if dofix then
              begin
                hreg:=getaddressregister(list);
                list.concat(taicpu.op_ref_reg(A_LEA,S_L,bref,hreg));
                list.concat(taicpu.op_reg_ref(A_MOVE,S_L{TCGSize2OpSize[fromsize]},hreg,bref));
                exit;
              end;
          end;
        list.concat(taicpu.op_ref_ref(A_MOVE,TCGSize2OpSize[fromsize],aref,bref));
      end;


    procedure tcg68k.a_load_reg_reg(list : TAsmList;fromsize,tosize : tcgsize;reg1,reg2 : tregister);
      begin
         { move to destination register }
         list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg1,reg2));
         { zero/sign extend register to 32-bit }
         sign_extend(list, fromsize, reg2);
      end;


    procedure tcg68k.a_load_ref_reg(list : TAsmList;fromsize,tosize : tcgsize;const ref : treference;register : tregister);
      var
       href : treference;
      begin
         href:=ref;
         fixref(list,href);
         list.concat(taicpu.op_ref_reg(A_MOVE,TCGSize2OpSize[fromsize],href,register));
         { extend the value in the register }
         sign_extend(list, tosize, register);
      end;


    procedure tcg68k.a_loadaddr_ref_reg(list : TAsmList;const ref : treference;r : tregister);
     var
       href : treference;
//       p: pointer;
      begin
         { TODO: FIX ME!!! take a look on this mess again...}
//        if getregtype(r)=R_ADDRESSREGISTER then
//          begin
//            writeln('address reg?!?');
//            p:=nil; dword(p^):=0; {DEBUG CODE... :D )
//            internalerror(2002072901);
//          end;
        href:=ref;
        fixref(list, href);
        list.concat(taicpu.op_ref_reg(A_LEA,S_L,href,r));
      end;


    procedure tcg68k.a_loadfpu_reg_reg(list: TAsmList; fromsize, tosize: tcgsize; reg1, reg2: tregister);
      begin
        { in emulation mode, only 32-bit single is supported }
        if cs_fp_emulation in current_settings.moduleswitches then
          list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg1,reg2))
        else
          list.concat(taicpu.op_reg_reg(A_FMOVE,tcgsize2opsize[tosize],reg1,reg2));
      end;


    procedure tcg68k.a_loadfpu_ref_reg(list: TAsmList; fromsize, tosize: tcgsize; const ref: treference; reg: tregister);
     var
      opsize : topsize;
      href : treference;
      tmpreg : tregister;
      begin
        opsize := tcgsize2opsize[fromsize];
        { extended is not supported, since it is not available on Coldfire }
        if opsize = S_FX then
          internalerror(20020729);
        href := ref;
        fixref(list,href);
        { in emulation mode, only 32-bit single is supported }
        if cs_fp_emulation in current_settings.moduleswitches then
           list.concat(taicpu.op_ref_reg(A_MOVE,S_L,href,reg))
        else
           begin
             list.concat(taicpu.op_ref_reg(A_FMOVE,opsize,href,reg));
             if (tosize < fromsize) then
               a_loadfpu_reg_reg(list,fromsize,tosize,reg,reg);
           end;
      end;

    procedure tcg68k.a_loadfpu_reg_ref(list: TAsmList; fromsize,tosize: tcgsize; reg: tregister; const ref: treference);
      var
       opsize : topsize;
      begin
        opsize := tcgsize2opsize[tosize];
        { extended is not supported, since it is not available on Coldfire }
        if opsize = S_FX then
          internalerror(20020729);
        { in emulation mode, only 32-bit single is supported }
        if cs_fp_emulation in current_settings.moduleswitches then
          list.concat(taicpu.op_reg_ref(A_MOVE,S_L,reg, ref))
        else
          list.concat(taicpu.op_reg_ref(A_FMOVE,opsize,reg, ref));
      end;


    procedure tcg68k.a_loadmm_reg_reg(list: TAsmList;fromsize,tosize : tcgsize; reg1, reg2: tregister;shuffle : pmmshuffle);
      begin
        internalerror(20020729);
      end;


    procedure tcg68k.a_loadmm_ref_reg(list: TAsmList;fromsize,tosize : tcgsize; const ref: treference; reg: tregister;shuffle : pmmshuffle);
      begin
        internalerror(20020729);
      end;


    procedure tcg68k.a_loadmm_reg_ref(list: TAsmList;fromsize,tosize : tcgsize; reg: tregister; const ref: treference;shuffle : pmmshuffle);
      begin
        internalerror(20020729);
      end;


    procedure tcg68k.a_loadmm_reg_cgpara(list: TAsmList; size: tcgsize; reg: tregister;const locpara : TCGPara;shuffle : pmmshuffle);
      begin
        internalerror(20020729);
      end;


    procedure tcg68k.a_op_const_reg(list : TAsmList; Op: TOpCG; size: tcgsize; a: tcgint; reg: TRegister);
      var
       scratch_reg : tregister;
       scratch_reg2: tregister;
       opcode : tasmop;
       r,r2 : Tregister;
      begin
        optimize_op_const(op, a);
        opcode := topcg2tasmop[op];
        case op of
          OP_NONE :
            begin
              { Opcode is optimized away }
            end;
          OP_MOVE :
            begin
              { Optimized, replaced with a simple load }
              a_load_const_reg(list,size,a,reg);
            end;
          OP_ADD :
              begin
                if (a >= 1) and (a <= 8) then
                    list.concat(taicpu.op_const_reg(A_ADDQ,S_L,a, reg))
                else
                  begin
                    { all others, including coldfire }
                    list.concat(taicpu.op_const_reg(A_ADD,S_L,a, reg));
                  end;
              end;
          OP_AND,
          OP_OR:
              begin
                if isaddressregister(reg) then
                  begin
                    { use scratch register (there is a anda/ora though...) }
                    scratch_reg:=getintregister(list,OS_INT);
                    list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg,scratch_reg));
                    list.concat(taicpu.op_const_reg(opcode,S_L,longint(a),scratch_reg));
                    list.concat(taicpu.op_reg_reg(A_MOVE,S_L,scratch_reg,reg));
                  end
                else
                  list.concat(taicpu.op_const_reg(topcg2tasmop[op],S_L,longint(a), reg));
              end;
          OP_DIV :
              begin
                 internalerror(20020816);
              end;
          OP_IDIV :
              begin
                 internalerror(20020816);
              end;
          OP_IMUL :
              begin
                if current_settings.cputype<>cpu_MC68020 then
                   begin
                     r:=NR_D0;
                     r2:=NR_D1;
                     cg.getcpuregister(list,NR_D0);
                     cg.getcpuregister(list,NR_D1);
                     list.concat(taicpu.op_const_reg(A_MOVE,S_L,a, r));
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg, r2));
                     cg.a_call_name(list,'FPC_MUL_LONGINT',false);
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,r, reg));
                     cg.ungetcpuregister(list,r);
                     cg.ungetcpuregister(list,r2);

                   end
                  else
                    begin
                      if (isaddressregister(reg)) then
                       begin
                         scratch_reg := getintregister(list,OS_INT);
                         list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg, scratch_reg));
                         list.concat(taicpu.op_const_reg(A_MULS,S_L,a,scratch_reg));
                         list.concat(taicpu.op_reg_reg(A_MOVE,S_L,scratch_reg,reg));
                       end
                      else
                         list.concat(taicpu.op_const_reg(A_MULS,S_L,a,reg));
                    end;
              end;
          OP_MUL :
              begin
                 if current_settings.cputype<>cpu_MC68020 then
                   begin
                     r:=NR_D0;
                     r2:=NR_D1;
                     cg.getcpuregister(list,NR_D0);
                     cg.getcpuregister(list,NR_D1);
                     list.concat(taicpu.op_const_reg(A_MOVE,S_L,a, r));
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg, r2));
                     cg.a_call_name(list,'FPC_MUL_DWORD',false);
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,r, reg));
                     cg.ungetcpuregister(list,r);
                     cg.ungetcpuregister(list,r2);
                   end
                  else
                    begin
                      if (isaddressregister(reg)) then
                       begin
                         scratch_reg := getintregister(list,OS_INT);
                         list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg, scratch_reg));
                         list.concat(taicpu.op_const_reg(A_MULU,S_L,a,scratch_reg));
                         list.concat(taicpu.op_reg_reg(A_MOVE,S_L,scratch_reg,reg));
                       end
                      else
                         list.concat(taicpu.op_const_reg(A_MULU,S_L,a,reg));
                    end;
              end;
          OP_SAR,
          OP_SHL,
          OP_SHR :
              begin
                if (a >= 1) and (a <= 8) then
                 begin
                   { not allowed to shift an address register }
                   if (isaddressregister(reg)) then
                     begin
                       scratch_reg := getintregister(list,OS_INT);
                       list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg, scratch_reg));
                       list.concat(taicpu.op_const_reg(opcode,S_L,a, scratch_reg));
                       list.concat(taicpu.op_reg_reg(A_MOVE,S_L,scratch_reg,reg));
                     end
                   else
                     list.concat(taicpu.op_const_reg(opcode,S_L,a, reg));
                 end
                else
                 begin
                   { we must load the data into a register ... :() }
                   scratch_reg := cg.getintregister(list,OS_INT);
                   list.concat(taicpu.op_const_reg(A_MOVE,S_L,a, scratch_reg));
                   { again... since shifting with address register is not allowed }
                   if (isaddressregister(reg)) then
                     begin
                       scratch_reg2 := cg.getintregister(list,OS_INT);
                       list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg, scratch_reg2));
                       list.concat(taicpu.op_reg_reg(opcode,S_L,scratch_reg, scratch_reg2));
                       list.concat(taicpu.op_reg_reg(A_MOVE,S_L,scratch_reg2,reg));
                     end
                   else
                     list.concat(taicpu.op_reg_reg(opcode,S_L,scratch_reg, reg));
                 end;
              end;
          OP_SUB :
              begin
                if (a >= 1) and (a <= 8) then
                    list.concat(taicpu.op_const_reg(A_SUBQ,S_L,a,reg))
                else
                  begin
                    { all others, including coldfire }
                    list.concat(taicpu.op_const_reg(A_SUB,S_L,a, reg));
                  end;
              end;
          OP_XOR :
              begin
                list.concat(taicpu.op_const_reg(A_EORI,S_L,a, reg));
              end;
        else
            internalerror(20020729);
         end;
      end;

{
    procedure tcg68k.a_op_const_ref(list : TAsmList; Op: TOpCG; size: TCGSize; a: tcgint; const ref: TReference);
      var
        opcode: tasmop;
      begin
        writeln('a_op_const_ref');

        optimize_op_const(op, a);
        opcode := topcg2tasmop[op];
        case op of
          OP_NONE :
            begin
              { opcode was optimized away }
            end;
          OP_MOVE :
            begin
              { Optimized, replaced with a simple load }
              a_load_const_ref(list,size,a,ref);
            end;
          else
            begin
              internalerror(2007010101);
            end;
        end;
      end;
}

    procedure tcg68k.a_op_reg_reg(list : TAsmList; Op: TOpCG; size: TCGSize; reg1, reg2: TRegister);
      var
       hreg1,hreg2,r,r2: tregister;
      begin
        case op of
          OP_ADD :
              begin
                 if current_settings.cputype = cpu_ColdFire then
                  begin
                    { operation only allowed only a longword }
                    sign_extend(list, size, reg1);
                    sign_extend(list, size, reg2);
                    list.concat(taicpu.op_reg_reg(A_ADD,S_L,reg1, reg2));
                  end
                 else
                  begin
                    list.concat(taicpu.op_reg_reg(A_ADD,TCGSize2OpSize[size],reg1, reg2));
                  end;
              end;
          OP_AND,OP_OR,
          OP_SAR,OP_SHL,
          OP_SHR,OP_SUB,OP_XOR :
              begin
                 { load to data registers }
                 if (isaddressregister(reg1)) then
                   begin
                     hreg1 := getintregister(list,OS_INT);
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg1,hreg1));
                   end
                 else
                   hreg1 := reg1;

                 if (isaddressregister(reg2))  then
                   begin
                      hreg2:= getintregister(list,OS_INT);
                      list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg2,hreg2));
                   end
                 else
                   hreg2 := reg2;

                 if current_settings.cputype = cpu_ColdFire then
                  begin
                    { operation only allowed only a longword }
                    {!***************************************
                      in the case of shifts, the value to
                      shift by, should already be valid, so
                      no need to sign extend the value
                     !
                    }
                    if op in [OP_AND,OP_OR,OP_SUB,OP_XOR] then
                       sign_extend(list, size, hreg1);
                    sign_extend(list, size, hreg2);
                    list.concat(taicpu.op_reg_reg(topcg2tasmop[op],S_L,hreg1, hreg2));
                  end
                 else
                  begin
                    list.concat(taicpu.op_reg_reg(topcg2tasmop[op],TCGSize2OpSize[size],hreg1, hreg2));
                  end;

                 { move back result into destination register }
                 if reg2 <> hreg2 then
                   begin
                      list.concat(taicpu.op_reg_reg(A_MOVE,S_L,hreg2,reg2));
                   end;
              end;
          OP_DIV :
              begin
                 internalerror(20020816);
              end;
          OP_IDIV :
              begin
                 internalerror(20020816);
              end;
          OP_IMUL :
              begin
                 sign_extend(list, size,reg1);
                 sign_extend(list, size,reg2);
                 if current_settings.cputype = cpu_MC68000 then
                   begin
                     r:=NR_D0;
                     r2:=NR_D1;
                     cg.getcpuregister(list,NR_D0);
                     cg.getcpuregister(list,NR_D1);
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg1, r));
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg2, r2));
                     cg.a_call_name(list,'FPC_MUL_LONGINT',false);
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,r, reg2));
                     cg.ungetcpuregister(list,r);
                     cg.ungetcpuregister(list,r2);
                   end
                  else
                    begin
//                     writeln('doing 68020');

                     if (isaddressregister(reg1)) then
                       hreg1 := getintregister(list,OS_INT)
                     else
                       hreg1 := reg1;
                     if (isaddressregister(reg2))  then
                       hreg2:= getintregister(list,OS_INT)
                     else
                       hreg2 := reg2;

                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg1,hreg1));
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg2,hreg2));

                     list.concat(taicpu.op_reg_reg(A_MULS,S_L,reg1,reg2));

                     { move back result into destination register }

                     if reg2 <> hreg2 then
                       begin
                          list.concat(taicpu.op_reg_reg(A_MOVE,S_L,hreg2,reg2));
                       end;
                    end;
              end;
          OP_MUL :
              begin
                 sign_extend(list, size,reg1);
                 sign_extend(list, size,reg2);
                 if current_settings.cputype <> cpu_MC68020 then
                   begin
                     r:=NR_D0;
                     r2:=NR_D1;
                     cg.getcpuregister(list,NR_D0);
                     cg.getcpuregister(list,NR_D1);
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg1, r));
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg2, r2));
                     cg.a_call_name(list,'FPC_MUL_DWORD',false);
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,r, reg2));
                     cg.ungetcpuregister(list,r);
                     cg.ungetcpuregister(list,r2);
                   end
                  else
                    begin
                     if (isaddressregister(reg1)) then
                      begin
                       hreg1 := cg.getintregister(list,OS_INT);
                       list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg1,hreg1));
                      end
                     else
                       hreg1 := reg1;

                     if (isaddressregister(reg2))  then
                      begin
                       hreg2:= cg.getintregister(list,OS_INT);
                       list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg2,hreg2));
                      end
                     else
                       hreg2 := reg2;

                     list.concat(taicpu.op_reg_reg(A_MULU,S_L,reg1,reg2));

                     { move back result into destination register }
                     if reg2<>hreg2 then
                       begin
                          list.concat(taicpu.op_reg_reg(A_MOVE,S_L,hreg2,reg2));
                       end;
                    end;
              end;
          OP_NEG,
          OP_NOT :
              Begin
                { if there are two operands, move the register,
                  since the operation will only be done on the result
                  register.
                }
                if reg1 <> NR_NO then
                  cg.a_load_reg_reg(current_asmdata.CurrAsmList,OS_INT,OS_INT,reg1,reg2);

                if (isaddressregister(reg2)) then
                  begin
                     hreg2 := getintregister(list,OS_INT);
                     list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg2,hreg2));
                   end
                  else
                    hreg2 := reg2;

                { coldfire only supports long version }
                if current_settings.cputype = cpu_ColdFire then
                  begin
                    sign_extend(list, size,hreg2);
                    list.concat(taicpu.op_reg(topcg2tasmop[op],S_L,hreg2));
                  end
                else
                  begin
                    list.concat(taicpu.op_reg(topcg2tasmop[op],TCGSize2OpSize[size],hreg2));
                  end;

                if reg2 <> hreg2 then
                  begin
                    list.concat(taicpu.op_reg_reg(A_MOVE,S_L,hreg2,reg2));
                  end;

              end;
        else
            internalerror(20020729);
         end;
      end;



    procedure tcg68k.a_cmp_const_reg_label(list : TAsmList;size : tcgsize;cmp_op : topcmp;a : tcgint;reg : tregister;
            l : tasmlabel);
      var
       hregister : tregister;
      begin
       if a = 0 then
         begin
           list.concat(taicpu.op_reg(A_TST,TCGSize2OpSize[size],reg));
         end
       else
         begin
           if (current_settings.cputype = cpu_ColdFire) then
             begin
               {
                 only longword comparison is supported,
                 and only on data registers.
               }
               hregister := getintregister(list,OS_INT);
               { always move to a data register }
               list.concat(taicpu.op_reg_reg(A_MOVE,S_L,reg,hregister));
               { sign/zero extend the register }
               sign_extend(list, size,hregister);
               list.concat(taicpu.op_const_reg(A_CMPI,S_L,a,hregister));
             end
           else
             begin
               list.concat(taicpu.op_const_reg(A_CMPI,TCGSize2OpSize[size],a,reg));
             end;
         end;
         { emit the actual jump to the label }
         a_jmp_cond(list,cmp_op,l);
      end;

    procedure tcg68k.a_cmp_reg_reg_label(list : TAsmList;size : tcgsize;cmp_op : topcmp;reg1,reg2 : tregister;l : tasmlabel);
      begin
         list.concat(taicpu.op_reg_reg(A_CMP,tcgsize2opsize[size],reg1,reg2));
         { emit the actual jump to the label }
         a_jmp_cond(list,cmp_op,l);
      end;

    procedure tcg68k.a_jmp_name(list: TAsmList; const s: string);
      var
       ai: taicpu;
      begin
         ai := Taicpu.op_sym(A_JMP,S_NO,current_asmdata.RefAsmSymbol(s));
         ai.is_jmp := true;
         list.concat(ai);
      end;

    procedure tcg68k.a_jmp_always(list : TAsmList;l: tasmlabel);
      var
       ai: taicpu;
      begin
         ai := Taicpu.op_sym(A_JMP,S_NO,l);
         ai.is_jmp := true;
         list.concat(ai);
      end;

    procedure tcg68k.a_jmp_flags(list : TAsmList;const f : TResFlags;l: tasmlabel);
       var
         ai : taicpu;
       begin
         ai := Taicpu.op_sym(A_BXX,S_NO,l);
         ai.SetCondition(flags_to_cond(f));
         ai.is_jmp := true;
         list.concat(ai);
       end;

    procedure tcg68k.g_flags2reg(list: TAsmList; size: TCgSize; const f: tresflags; reg: TRegister);
       var
         ai : taicpu;
         hreg : tregister;
       begin
          { move to a Dx register? }
          if (isaddressregister(reg)) then
            begin
              hreg := getintregister(list,OS_INT);
              a_load_const_reg(list,size,0,hreg);
              ai:=Taicpu.Op_reg(A_Sxx,S_B,hreg);
              ai.SetCondition(flags_to_cond(f));
              list.concat(ai);

              if (current_settings.cputype = cpu_ColdFire) then
                begin
                 { neg.b does not exist on the Coldfire
                   so we need to sign extend the value
                   before doing a neg.l
                 }
                 list.concat(taicpu.op_reg(A_EXTB,S_L,hreg));
                 list.concat(taicpu.op_reg(A_NEG,S_L,hreg));
                end
              else
                begin
                  list.concat(taicpu.op_reg(A_NEG,S_B,hreg));
                end;
             list.concat(taicpu.op_reg_reg(A_MOVE,S_L,hreg,reg));
            end
          else
          begin
            a_load_const_reg(list,size,0,reg);
            ai:=Taicpu.Op_reg(A_Sxx,S_B,reg);
            ai.SetCondition(flags_to_cond(f));
            list.concat(ai);

            if (current_settings.cputype = cpu_ColdFire) then
              begin
                 { neg.b does not exist on the Coldfire
                   so we need to sign extend the value
                   before doing a neg.l
                 }
                 list.concat(taicpu.op_reg(A_EXTB,S_L,reg));
                 list.concat(taicpu.op_reg(A_NEG,S_L,reg));
              end
            else
              begin
               list.concat(taicpu.op_reg(A_NEG,S_B,reg));
              end;
          end;
       end;



    procedure tcg68k.g_concatcopy(list : TAsmList;const source,dest : treference;len : tcgint);

     var
         helpsize : longint;
         i : byte;
         reg8,reg32 : tregister;
         swap : boolean;
         hregister : tregister;
         iregister : tregister;
         jregister : tregister;
         hp1 : treference;
         hp2 : treference;
         hl : tasmlabel;
         hl2: tasmlabel;
         popaddress : boolean;
         srcref,dstref : treference;

      begin
         popaddress := false;

//	 writeln('concatcopy:',len);

         { this should never occur }
         if len > 65535 then
           internalerror(0);

         hregister := getintregister(list,OS_INT);
//         if delsource then
//            reference_release(list,source);

         { from 12 bytes movs is being used }
         if {(not loadref) and} ((len<=8) or (not(cs_opt_size in current_settings.optimizerswitches) and (len<=12))) then
           begin
              srcref := source;
              dstref := dest;
              helpsize:=len div 4;
              { move a dword x times }
              for i:=1 to helpsize do
                begin
                   a_load_ref_reg(list,OS_INT,OS_INT,srcref,hregister);
                   a_load_reg_ref(list,OS_INT,OS_INT,hregister,dstref);
                   inc(srcref.offset,4);
                   inc(dstref.offset,4);
                   dec(len,4);
                end;
              { move a word }
              if len>1 then
                begin
                   a_load_ref_reg(list,OS_16,OS_16,srcref,hregister);
                   a_load_reg_ref(list,OS_16,OS_16,hregister,dstref);
                   inc(srcref.offset,2);
                   inc(dstref.offset,2);
                   dec(len,2);
                end;
              { move a single byte }
              if len>0 then
                begin
                   a_load_ref_reg(list,OS_8,OS_8,srcref,hregister);
                   a_load_reg_ref(list,OS_8,OS_8,hregister,dstref);
                end
           end
         else
           begin
              iregister:=getaddressregister(list);
              jregister:=getaddressregister(list);
              { reference for move (An)+,(An)+ }
              reference_reset(hp1,source.alignment);
              hp1.base := iregister;   { source register }
              hp1.direction := dir_inc;
              reference_reset(hp2,dest.alignment);
              hp2.base := jregister;
              hp2.direction := dir_inc;
              { iregister = source }
              { jregister = destination }

{              if loadref then
                 cg.a_load_ref_reg(list,OS_INT,OS_INT,source,iregister)
              else}
                 a_loadaddr_ref_reg(list,source,iregister);

              a_loadaddr_ref_reg(list,dest,jregister);

              { double word move only on 68020+ machines }
              { because of possible alignment problems   }
              { use fast loop mode }
              if (current_settings.cputype=cpu_MC68020) then
                begin
                   helpsize := len - len mod 4;
                   len := len mod 4;
                   list.concat(taicpu.op_const_reg(A_MOVE,S_L,helpsize div 4,hregister));
                   current_asmdata.getjumplabel(hl2);
                   a_jmp_always(list,hl2);
                   current_asmdata.getjumplabel(hl);
                   a_label(list,hl);
                   list.concat(taicpu.op_ref_ref(A_MOVE,S_L,hp1,hp2));
                   a_label(list,hl2);
                   list.concat(taicpu.op_reg_sym(A_DBRA,S_L,hregister,hl));
                   if len > 1 then
                     begin
                        dec(len,2);
                        list.concat(taicpu.op_ref_ref(A_MOVE,S_W,hp1,hp2));
                     end;
                   if len = 1 then
                     list.concat(taicpu.op_ref_ref(A_MOVE,S_B,hp1,hp2));
                end
              else
                begin
                   { Fast 68010 loop mode with no possible alignment problems }
                   helpsize := len;
                   list.concat(taicpu.op_const_reg(A_MOVE,S_L,helpsize,hregister));
                   current_asmdata.getjumplabel(hl2);
                   a_jmp_always(list,hl2);
                   current_asmdata.getjumplabel(hl);
                   a_label(list,hl);
                   list.concat(taicpu.op_ref_ref(A_MOVE,S_B,hp1,hp2));
                   a_label(list,hl2);
                   if current_settings.cputype=cpu_coldfire then
                     begin
                       { Coldfire does not support DBRA }
                       list.concat(taicpu.op_const_reg(A_SUB,S_L,1,hregister));
                       list.concat(taicpu.op_sym(A_BMI,S_L,hl));
                     end
                   else
                     list.concat(taicpu.op_reg_sym(A_DBRA,S_L,hregister,hl));
                end;

              { restore the registers that we have just used olny if they are used! }
              if jregister = NR_A1 then
                hp2.base := NR_NO;
              if iregister = NR_A0 then
                hp1.base := NR_NO;
//              reference_release(list,hp1);
//              reference_release(list,hp2);
           end;

//           if delsource then
//               tg.ungetiftemp(list,source);
    end;

    procedure tcg68k.g_overflowcheck(list: TAsmList; const l:tlocation; def:tdef);
      begin
      end;

    procedure tcg68k.g_proc_entry(list: TAsmList; localsize: longint; nostackframe:boolean);
      var
        r,rsp: TRegister;
        ref  : TReference;
      begin
{$ifdef DEBUG_CHARLIE}
//        writeln('proc entry, localsize:',localsize);
{$endif DEBUG_CHARLIE}

        if not nostackframe then
          begin
	    if localsize<>0 then
	      begin
	        { size can't be negative }
		if (localsize < 0) then
		  internalerror(2006122601);

                { Not to complicate the code generator too much, and since some }
                { of the systems only support this format, the localsize cannot }
                { exceed 32K in size.                                           }
                if (localsize > high(smallint)) then
                  CGMessage(cg_e_localsize_too_big);

                list.concat(taicpu.op_reg_const(A_LINK,S_W,NR_FRAME_POINTER_REG,-localsize));
	      end
	    else
	      begin
	        list.concat(taicpu.op_reg_const(A_LINK,S_W,NR_FRAME_POINTER_REG,0));
(*
		{ FIXME! - Carl's original code uses this method. However,
		  according to the 68060 users manual, a LINK is faster than
		  two moves. So, use a link in #0 case too, for now. I'm not
		  really sure tho', that LINK supports #0 disposition, but i
		  see no reason why it shouldn't support it. (KB) }

	        { when localsize = 0, use two moves, instead of link }
		r:=NR_FRAME_POINTER_REG;
		rsp:=NR_STACK_POINTER_REG;

	        reference_reset_base(ref,NR_STACK_POINTER_REG,0);
		ref.direction:=dir_dec;
                list.concat(taicpu.op_reg_ref(A_MOVE,S_L,r,ref));
                list.concat(taicpu.op_reg_reg(A_MOVE,S_L,rsp,r));
		*)
	      end;
          end;
      end;

{    procedure tcg68k.g_restore_frame_pointer(list : TAsmList);
      var
        r:Tregister;
      begin
        r:=NR_FRAME_POINTER_REG;
        list.concat(taicpu.op_reg(A_UNLK,S_NO,r));
      end;
}

    procedure tcg68k.g_proc_exit(list : TAsmList; parasize: longint; nostackframe: boolean);
      var
        r,hregister : TRegister;
        localsize: tcgint;
        spr : TRegister;
        fpr : TRegister;
        ref : TReference;
      begin
        if not nostackframe then
          begin
            localsize := current_procinfo.calc_stackframe_size;
{$ifdef DEBUG_CHARLIE}
//            writeln('proc exit with stackframe, size:',localsize,' parasize:',parasize);
{$endif DEBUG_CHARLIE}
            list.concat(taicpu.op_reg(A_UNLK,S_NO,NR_FRAME_POINTER_REG));
	    parasize := parasize - target_info.first_parm_offset; { i'm still not 100% confident that this is
	                                                            correct here, but at least it looks less
								    hacky, and makes some sense (KB) }
            if (parasize<>0) then
              begin
                { only 68020+ supports RTD, so this needs another code path
                  for 68000 and Coldfire (KB) }
{ TODO: 68020+ only code generation, without fallback}
                if current_settings.cputype=cpu_mc68020 then
                  list.concat(taicpu.op_const(A_RTD,S_NO,parasize))
                else
                  begin

                    { We must pull the PC Counter from the stack, before  }
                    { restoring the stack pointer, otherwise the PC would }
                    { point to nowhere!                                   }

                    { save the PC counter (pop it from the stack)         }
                    //hregister:=cg.getaddressregister(list);
                    hregister:=NR_A3;
                    cg.a_reg_alloc(list,hregister);
                    reference_reset_base(ref,NR_STACK_POINTER_REG,0,4);
                    ref.direction:=dir_inc;
                    list.concat(taicpu.op_ref_reg(A_MOVE,S_L,ref,hregister));
                    { can we do a quick addition ... }
                    r:=NR_SP;
                    if (parasize > 0) and (parasize < 9) then
                       list.concat(taicpu.op_const_reg(A_ADDQ,S_L,parasize,r))
                    else { nope ... }
                       list.concat(taicpu.op_const_reg(A_ADD,S_L,parasize,r));

                    { restore the PC counter (push it on the stack)       }
                    reference_reset_base(ref,NR_STACK_POINTER_REG,0,4);
                    ref.direction:=dir_dec;
                    cg.a_reg_alloc(list,hregister);
                    list.concat(taicpu.op_reg_ref(A_MOVE,S_L,hregister,ref));
                    list.concat(taicpu.op_none(A_RTS,S_NO));
                  end;
              end
            else
              list.concat(taicpu.op_none(A_RTS,S_NO));
          end
        else
          begin
{$ifdef DEBUG_CHARLIE}
//            writeln('proc exit, no stackframe');
{$endif DEBUG_CHARLIE}
            list.concat(taicpu.op_none(A_RTS,S_NO));
          end;

//         writeln('g_proc_exit');
         { Routines with the poclearstack flag set use only a ret.
           also  routines with parasize=0     }
           (*
         if current_procinfo.procdef.proccalloption in clearstack_pocalls then
           begin
             { complex return values are removed from stack in C code PM }
             if paramanager.ret_in_param(current_procinfo.procdef.returndef,current_procinfo.procdef.proccalloption) then
               list.concat(taicpu.op_const(A_RTD,S_NO,4))
             else
               list.concat(taicpu.op_none(A_RTS,S_NO));
           end
         else if (parasize=0) then
           begin
             list.concat(taicpu.op_none(A_RTS,S_NO));
           end
         else
           begin
            { return with immediate size possible here
              signed!
              RTD is not supported on the coldfire     }
            if (current_settings.cputype=cpu_MC68020) and (parasize<$7FFF) then
                list.concat(taicpu.op_const(A_RTD,S_NO,parasize))
            { manually restore the stack }
            else
              begin
                { We must pull the PC Counter from the stack, before  }
                { restoring the stack pointer, otherwise the PC would }
                { point to nowhere!                                   }

                { save the PC counter (pop it from the stack)         }
                hregister:=NR_A3;
                cg.a_reg_alloc(list,hregister);
                reference_reset_base(ref,NR_STACK_POINTER_REG,0);
                ref.direction:=dir_inc;
                list.concat(taicpu.op_ref_reg(A_MOVE,S_L,ref,hregister));
                { can we do a quick addition ... }
                r:=NR_SP;
                if (parasize > 0) and (parasize < 9) then
                   list.concat(taicpu.op_const_reg(A_ADDQ,S_L,parasize,r))
                else { nope ... }
                   list.concat(taicpu.op_const_reg(A_ADD,S_L,parasize,r));

                { restore the PC counter (push it on the stack)       }
                reference_reset_base(ref,NR_STACK_POINTER_REG,0);
                ref.direction:=dir_dec;
                cg.a_reg_alloc(list,hregister);
                list.concat(taicpu.op_reg_ref(A_MOVE,S_L,hregister,ref));
                list.concat(taicpu.op_none(A_RTS,S_NO));
               end;
           end;
           *)
      end;


    procedure Tcg68k.g_save_registers(list:TAsmList);
      var
        tosave : tcpuregisterset;
        ref : treference;
      begin
      {!!!!!
        tosave:=std_saved_registers;
        { only save the registers which are not used and must be saved }
        tosave:=tosave*(rg[R_INTREGISTER].used_in_proc+rg[R_ADDRESSREGISTER].used_in_proc);
        reference_reset_base(ref,NR_STACK_POINTER_REG,0);
        ref.direction:=dir_dec;
        if tosave<>[] then
          list.concat(taicpu.op_regset_ref(A_MOVEM,S_L,tosave,ref));
      }
      end;


    procedure Tcg68k.g_restore_registers(list:TAsmList);
      var
        torestore : tcpuregisterset;
        r:Tregister;
        ref : treference;
      begin
      {!!!!!!!!
        torestore:=std_saved_registers;
        { should be intersected with used regs, no ? }
        torestore:=torestore*(rg[R_INTREGISTER].used_in_proc+rg[R_ADDRESSREGISTER].used_in_proc);
        reference_reset_base(ref,NR_STACK_POINTER_REG,0);
        ref.direction:=dir_inc;
        if torestore<>[] then
          list.concat(taicpu.op_ref_regset(A_MOVEM,S_L,ref,torestore));
      }
      end;

{
    procedure tcg68k.g_save_all_registers(list : TAsmList);
      begin
      end;

    procedure tcg68k.g_restore_all_registers(list : TAsmList;const funcretparaloc:TCGPara);
      begin
      end;
}
    procedure tcg68k.sign_extend(list: TAsmList;_oldsize : tcgsize; reg: tregister);
      begin
        case _oldsize of
         { sign extend }
         OS_S8:
              begin
                if (isaddressregister(reg)) then
                   internalerror(20020729);
                if (current_settings.cputype = cpu_MC68000) then
                  begin
                    list.concat(taicpu.op_reg(A_EXT,S_W,reg));
                    list.concat(taicpu.op_reg(A_EXT,S_L,reg));
                  end
                else
                  begin
//    		    list.concat(tai_comment.create(strpnew('sign extend byte')));
                    list.concat(taicpu.op_reg(A_EXTB,S_L,reg));
                  end;
              end;
         OS_S16:
              begin
                if (isaddressregister(reg)) then
                   internalerror(20020729);
//    		list.concat(tai_comment.create(strpnew('sign extend word')));
                list.concat(taicpu.op_reg(A_EXT,S_L,reg));
              end;
         { zero extend }
         OS_8:
              begin
//    		list.concat(tai_comment.create(strpnew('zero extend byte')));
                list.concat(taicpu.op_const_reg(A_AND,S_L,$FF,reg));
              end;
         OS_16:
              begin
//    		list.concat(tai_comment.create(strpnew('zero extend word')));
                list.concat(taicpu.op_const_reg(A_AND,S_L,$FFFF,reg));
              end;
        end; { otherwise the size is already correct }
      end;

     procedure tcg68k.a_jmp_cond(list : TAsmList;cond : TOpCmp;l: tasmlabel);

       var
         ai : taicpu;

       begin
         if cond=OC_None then
           ai := Taicpu.Op_sym(A_JMP,S_NO,l)
         else
           begin
             ai:=Taicpu.Op_sym(A_Bxx,S_NO,l);
             ai.SetCondition(TOpCmp2AsmCond[cond]);
           end;
         ai.is_jmp:=true;
         list.concat(ai);
       end;


    procedure tcg68k.g_intf_wrapper(list: TAsmList; procdef: tprocdef; const labelname: string; ioffset: longint);
{
        procedure loadvmttor11;
        var
          href : treference;
        begin
          reference_reset_base(href,NR_R3,0);
          cg.a_load_ref_reg(list,OS_ADDR,OS_ADDR,href,NR_R11);
        end;

        procedure op_onr11methodaddr;
        var
          href : treference;
        begin
          if (procdef.extnumber=$ffff) then
            Internalerror(200006139);
          { call/jmp  vmtoffs(%eax) ; method offs }
          reference_reset_base(href,NR_R11,tobjectdef(procdef.struct).vmtmethodoffset(procdef.extnumber));
          if not((longint(href.offset) >= low(smallint)) and
                 (longint(href.offset) <= high(smallint))) then
            begin
              list.concat(taicpu.op_reg_reg_const(A_ADDIS,NR_R11,NR_R11,
                smallint((href.offset shr 16)+ord(smallint(href.offset and $ffff) < 0))));
              href.offset := smallint(href.offset and $ffff);
            end;
          list.concat(taicpu.op_reg_ref(A_LWZ,NR_R11,href));
          list.concat(taicpu.op_reg(A_MTCTR,NR_R11));
          list.concat(taicpu.op_none(A_BCTR));
        end;
}
      var
        make_global : boolean;
      begin
        if not(procdef.proctypeoption in [potype_function,potype_procedure]) then
          Internalerror(200006137);
        if not assigned(procdef.struct) or
           (procdef.procoptions*[po_classmethod, po_staticmethod,
             po_methodpointer, po_interrupt, po_iocheck]<>[]) then
          Internalerror(200006138);
        if procdef.owner.symtabletype<>ObjectSymtable then
          Internalerror(200109191);

        make_global:=false;
        if (not current_module.is_unit) or
           create_smartlink or
           (procdef.owner.defowner.owner.symtabletype=globalsymtable) then
          make_global:=true;

        if make_global then
          List.concat(Tai_symbol.Createname_global(labelname,AT_FUNCTION,0))
        else
          List.concat(Tai_symbol.Createname(labelname,AT_FUNCTION,0));

        { set param1 interface to self  }
//        g_adjust_self_value(list,procdef,ioffset);

        { case 4 }
        if (po_virtualmethod in procdef.procoptions) and
            not is_objectpascal_helper(procdef.struct) then
          begin
//            loadvmttor11;
//            op_onr11methodaddr;
          end
        { case 0 }
        else
//          list.concat(taicpu.op_sym(A_B,current_asmdata.RefAsmSymbol(procdef.mangledname)));

        List.concat(Tai_symbol_end.Createname(labelname));
      end;


{****************************************************************************}
{                               TCG64F68K                                    }
{****************************************************************************}
 procedure tcg64f68k.a_op64_reg_reg(list : TAsmList;op:TOpCG;size: tcgsize; regsrc,regdst : tregister64);
  var
   hreg1, hreg2 : tregister;
   opcode : tasmop;
  begin
//    writeln('a_op64_reg_reg');
    opcode := topcg2tasmop[op];
    case op of
      OP_ADD :
         begin
            { if one of these three registers is an address
              register, we'll really get into problems!
            }
            if isaddressregister(regdst.reglo) or
               isaddressregister(regdst.reghi) or
               isaddressregister(regsrc.reghi) then
                 internalerror(20020817);
            list.concat(taicpu.op_reg_reg(A_ADD,S_L,regsrc.reglo,regdst.reglo));
            list.concat(taicpu.op_reg_reg(A_ADDX,S_L,regsrc.reghi,regdst.reghi));
         end;
      OP_AND,OP_OR :
          begin
            { at least one of the registers must be a data register }
            if (isaddressregister(regdst.reglo) and
                isaddressregister(regsrc.reglo)) or
               (isaddressregister(regsrc.reghi) and
                isaddressregister(regdst.reghi))
               then
                 internalerror(20020817);
            cg.a_op_reg_reg(list,op,OS_32,regsrc.reglo,regdst.reglo);
            cg.a_op_reg_reg(list,op,OS_32,regsrc.reghi,regdst.reghi);
          end;
      { this is handled in 1st pass for 32-bit cpu's (helper call) }
      OP_IDIV,OP_DIV,
      OP_IMUL,OP_MUL: internalerror(2002081701);
      { this is also handled in 1st pass for 32-bit cpu's (helper call) }
      OP_SAR,OP_SHL,OP_SHR: internalerror(2002081702);
      OP_SUB:
         begin
            { if one of these three registers is an address
              register, we'll really get into problems!
            }
            if isaddressregister(regdst.reglo) or
               isaddressregister(regdst.reghi) or
               isaddressregister(regsrc.reghi) then
                 internalerror(20020817);
            list.concat(taicpu.op_reg_reg(A_SUB,S_L,regsrc.reglo,regdst.reglo));
            list.concat(taicpu.op_reg_reg(A_SUBX,S_L,regsrc.reghi,regdst.reghi));
         end;
      OP_XOR:
        begin
            if isaddressregister(regdst.reglo) or
               isaddressregister(regsrc.reglo) or
               isaddressregister(regsrc.reghi) or
               isaddressregister(regdst.reghi) then
                 internalerror(20020817);
            list.concat(taicpu.op_reg_reg(A_EOR,S_L,regsrc.reglo,regdst.reglo));
            list.concat(taicpu.op_reg_reg(A_EOR,S_L,regsrc.reghi,regdst.reghi));
        end;
    end; { end case }
  end;


 procedure tcg64f68k.a_op64_const_reg(list : TAsmList;op:TOpCG;size: tcgsize; value : int64;regdst : tregister64);
  var
   lowvalue : cardinal;
   highvalue : cardinal;
   hreg : tregister;
  begin
//    writeln('a_op64_const_reg');
    { is it optimized out ? }
//    if cg.optimize64_op_const_reg(list,op,value,reg) then
//       exit;

    lowvalue := cardinal(value);
    highvalue:= value shr 32;

   { the destination registers must be data registers }
   if  isaddressregister(regdst.reglo) or
       isaddressregister(regdst.reghi) then
         internalerror(20020817);
   case op of
      OP_ADD :
         begin
           hreg:=cg.getintregister(list,OS_INT);
           list.concat(taicpu.op_const_reg(A_MOVE,S_L,highvalue,hreg));
           list.concat(taicpu.op_const_reg(A_ADD,S_L,lowvalue,regdst.reglo));
           list.concat(taicpu.op_reg_reg(A_ADDX,S_L,hreg,regdst.reglo));
         end;
      OP_AND :
          begin
            list.concat(taicpu.op_const_reg(A_AND,S_L,lowvalue,regdst.reglo));
            list.concat(taicpu.op_const_reg(A_AND,S_L,highvalue,regdst.reglo));
          end;
      OP_OR :
          begin
            list.concat(taicpu.op_const_reg(A_OR,S_L,lowvalue,regdst.reglo));
            list.concat(taicpu.op_const_reg(A_OR,S_L,highvalue,regdst.reglo));
          end;
      { this is handled in 1st pass for 32-bit cpus (helper call) }
      OP_IDIV,OP_DIV,
      OP_IMUL,OP_MUL: internalerror(2002081701);
      { this is also handled in 1st pass for 32-bit cpus (helper call) }
      OP_SAR,OP_SHL,OP_SHR: internalerror(2002081702);
      OP_SUB:
         begin
           hreg:=cg.getintregister(list,OS_INT);
           list.concat(taicpu.op_const_reg(A_MOVE,S_L,highvalue,hreg));
           list.concat(taicpu.op_const_reg(A_SUB,S_L,lowvalue,regdst.reglo));
           list.concat(taicpu.op_reg_reg(A_SUBX,S_L,hreg,regdst.reglo));
         end;
      OP_XOR:
        begin
            list.concat(taicpu.op_const_reg(A_EOR,S_L,lowvalue,regdst.reglo));
            list.concat(taicpu.op_const_reg(A_EOR,S_L,highvalue,regdst.reglo));
        end;
    end; { end case }
  end;


procedure create_codegen;
  begin
    cg := tcg68k.create;
    cg64 :=tcg64f68k.create;
  end;

end.