fpc/compiler/z80/cgcpu.pas

{

    Copyright (c) 2008 by Florian Klaempfl
    Member of the Free Pascal development team

    This unit implements the code generator for the Z80

    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.

 ****************************************************************************
}
unit cgcpu;

{$i fpcdefs.inc}

  interface

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

    type
      tcgz80 = class(tcg)
        { true, if the next arithmetic operation should modify the flags }
        cgsetflags : boolean;
        procedure init_register_allocators;override;
        procedure done_register_allocators;override;

        function getaddressregister(list:TAsmList):TRegister;override;

        procedure a_load_const_cgpara(list : TAsmList;size : tcgsize;a : tcgint;const paraloc : TCGPara);override;
        procedure a_load_ref_cgpara(list : TAsmList;size : tcgsize;const r : treference;const paraloc : TCGPara);override;
        procedure a_loadaddr_ref_cgpara(list : TAsmList;const r : treference;const paraloc : TCGPara);override;
        procedure a_load_reg_cgpara(list : TAsmList; size : tcgsize;r : tregister; 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_op_const_reg(list : TAsmList; Op: TOpCG; size: TCGSize; a: tcgint; reg: TRegister); override;
        procedure a_op_reg_reg(list: TAsmList; Op: TOpCG; size: TCGSize; src, dst : TRegister); override;

        { move instructions }
        procedure a_load_const_reg(list : TAsmList; size: tcgsize; a : tcgint;reg : tregister);override;
        procedure a_load_reg_ref(list : TAsmList; fromsize, tosize: tcgsize; reg : tregister;const ref : treference);override;
        procedure a_load_ref_reg(list : TAsmList; fromsize, tosize : tcgsize;const Ref : treference;reg : tregister);override;
        procedure a_load_reg_reg(list : TAsmList; fromsize, tosize : tcgsize;reg1,reg2 : tregister);override;

        { fpu move instructions }
        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;

        {  comparison operations }
        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_proc_entry(list : TAsmList;localsize : longint;nostackframe:boolean);override;
        procedure g_proc_exit(list : TAsmList;parasize : longint;nostackframe:boolean); override;

        procedure a_loadaddr_ref_reg(list : TAsmList;const ref : treference;r : tregister);override;

        procedure g_concatcopy(list : TAsmList;const source,dest : treference;len : tcgint);override;
        procedure g_concatcopy_move(list : TAsmList;const source,dest : treference;len : tcgint);

        procedure g_overflowcheck(list: TAsmList; const l: tlocation; def: tdef); override;

        procedure g_save_registers(list : TAsmList);override;
        procedure g_restore_registers(list : TAsmList);override;

        procedure a_jmp_cond(list : TAsmList;cond : TOpCmp;l: tasmlabel);
        procedure fixref(list : TAsmList;var ref : treference);
        function normalize_ref(list : TAsmList;ref : treference;
          tmpreg : tregister) : treference;

        procedure emit_mov(list: TAsmList;reg2: tregister; reg1: tregister);

        procedure a_adjust_sp(list: TAsmList; value: longint);
        function GetLoad(const ref : treference) : tasmop;
        function GetStore(const ref: treference): tasmop;

      protected
        procedure a_op_reg_reg_internal(list: TAsmList; Op: TOpCG; size: TCGSize; src, srchi, dst, dsthi: TRegister);
        procedure a_op_const_reg_internal(list : TAsmList; Op: TOpCG; size: TCGSize; a: tcgint; reg, reghi: TRegister);
        procedure maybegetcpuregister(list : tasmlist; reg : tregister);
      end;

      tcg64fz80 = 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;reg : tregister64);override;
      end;

    function GetByteLoc(const loc : tlocation;nr :  byte) : tlocation;

    procedure create_codegen;

    const
      TOpCG2AsmOp: Array[topcg] of TAsmOp = (A_NONE,A_LD,A_ADD,A_AND,A_NONE,
                            A_NONE,A_NONE,A_NONE,A_NEG,A_CPL,A_OR,
                            A_SRA,A_SLA,A_SRL,A_SUB,A_XOR,A_RLCA,A_RRCA);
  implementation

    uses
       globals,verbose,systems,cutils,
       fmodule,
       symconst,symsym,symtable,
       tgobj,rgobj,
       procinfo,cpupi,
       paramgr;


    procedure tcgz80.init_register_allocators;
      begin
        inherited init_register_allocators;
        rg[R_INTREGISTER]:=trgintcpu.create(R_INTREGISTER,R_SUBWHOLE,
            [RS_BC,RS_DE,RS_HL],first_int_imreg,[]);
      end;


    procedure tcgz80.done_register_allocators;
      begin
        rg[R_INTREGISTER].free;
        // rg[R_ADDRESSREGISTER].free;
        inherited done_register_allocators;
      end;


    function tcgz80.getaddressregister(list: TAsmList): TRegister;
      begin
       Result:=getintregister(list,OS_ADDR);
      end;


    procedure tcgz80.a_load_reg_cgpara(list : TAsmList;size : tcgsize;r : tregister;const cgpara : tcgpara);

      procedure load_para_loc(r : TRegister;paraloc : PCGParaLocation);
        var
          ref : treference;
        begin
          paramanager.allocparaloc(list,paraloc);
          case paraloc^.loc of
             LOC_REGISTER,LOC_CREGISTER:
               a_load_reg_reg(list,paraloc^.size,paraloc^.size,r,paraloc^.register);
             LOC_REFERENCE,LOC_CREFERENCE:
               begin
                  reference_reset_base(ref,paraloc^.reference.index,paraloc^.reference.offset,ctempposinvalid,2,[]);
                  a_load_reg_ref(list,paraloc^.size,paraloc^.size,r,ref);
               end;
             else
               internalerror(2002071004);
          end;
        end;

      var
        i, i2 : longint;
        hp : PCGParaLocation;

      begin
{        if use_push(cgpara) then
          begin
            if tcgsize2size[cgpara.Size] > 2 then
              begin
                if tcgsize2size[cgpara.Size] <> 4 then
                  internalerror(2013031101);
                if cgpara.location^.Next = nil then
                  begin
                    if tcgsize2size[cgpara.location^.size] <> 4 then
                      internalerror(2013031101);
                  end
                else
                  begin
                    if tcgsize2size[cgpara.location^.size] <> 2 then
                      internalerror(2013031101);
                    if tcgsize2size[cgpara.location^.Next^.size] <> 2 then
                      internalerror(2013031101);
                    if cgpara.location^.Next^.Next <> nil then
                      internalerror(2013031101);
                  end;

                if tcgsize2size[cgpara.size]>cgpara.alignment then
                  pushsize:=cgpara.size
                else
                  pushsize:=int_cgsize(cgpara.alignment);
                pushsize2 := int_cgsize(tcgsize2size[pushsize] - 2);
                list.concat(taicpu.op_reg(A_PUSH,TCgsize2opsize[pushsize2],makeregsize(list,GetNextReg(r),pushsize2)));
                list.concat(taicpu.op_reg(A_PUSH,S_W,makeregsize(list,r,OS_16)));
              end
            else
              begin
                cgpara.check_simple_location;
                if tcgsize2size[cgpara.location^.size]>cgpara.alignment then
                  pushsize:=cgpara.location^.size
                else
                  pushsize:=int_cgsize(cgpara.alignment);
                list.concat(taicpu.op_reg(A_PUSH,TCgsize2opsize[pushsize],makeregsize(list,r,pushsize)));
              end;

          end
        else }
          begin
            if not(tcgsize2size[cgpara.Size] in [1..4]) then
              internalerror(2014011101);

            hp:=cgpara.location;

            i:=0;
            while i<tcgsize2size[cgpara.Size] do
              begin
                if not(assigned(hp)) then
                  internalerror(2014011102);

                inc(i, tcgsize2size[hp^.Size]);

                if hp^.Loc=LOC_REGISTER then
                  begin
                    load_para_loc(r,hp);
                    hp:=hp^.Next;
                    r:=GetNextReg(r);
                  end
                else
                  begin
                    load_para_loc(r,hp);

                    for i2:=1 to tcgsize2size[hp^.Size] do
                      r:=GetNextReg(r);

                    hp:=hp^.Next;
                  end;
              end;
            if assigned(hp) then
              internalerror(2014011103);
          end;
      end;


    procedure tcgz80.a_load_const_cgpara(list : TAsmList;size : tcgsize;a : tcgint;const paraloc : TCGPara);
      var
        i : longint;
        hp : PCGParaLocation;
        ref: treference;
      begin
        if not(tcgsize2size[paraloc.Size] in [1..4]) then
          internalerror(2014011101);

        hp:=paraloc.location;

        i:=1;
        while i<=tcgsize2size[paraloc.Size] do
          begin
            if not(assigned(hp)) then
              internalerror(2014011105);
             //paramanager.allocparaloc(list,hp);
             case hp^.loc of
               LOC_REGISTER,LOC_CREGISTER:
                 begin
                   if (tcgsize2size[hp^.size]<>1) or
                     (hp^.shiftval<>0) then
                     internalerror(2015041101);
                   a_load_const_reg(list,hp^.size,(a shr (8*(i-1))) and $ff,hp^.register);

                   inc(i,tcgsize2size[hp^.size]);
                   hp:=hp^.Next;
                 end;
               LOC_REFERENCE,LOC_CREFERENCE:
                 begin
                   reference_reset(ref,paraloc.alignment,[]);
                   ref.base:=hp^.reference.index;
                   ref.offset:=hp^.reference.offset;
                   a_load_const_ref(list,hp^.size,a shr (8*(i-1)),ref);

                   inc(i,tcgsize2size[hp^.size]);
                   hp:=hp^.Next;
                 end;
               else
                 internalerror(2002071004);
            end;
          end;
      end;


    procedure tcgz80.a_load_ref_cgpara(list : TAsmList;size : tcgsize;const r : treference;const paraloc : TCGPara);
      var
        tmpref, ref: treference;
        location: pcgparalocation;
        sizeleft: tcgint;
      begin
        location := paraloc.location;
        tmpref := r;
        sizeleft := paraloc.intsize;
        while assigned(location) do
          begin
            paramanager.allocparaloc(list,location);
            case location^.loc of
              LOC_REGISTER,LOC_CREGISTER:
                a_load_ref_reg(list,location^.size,location^.size,tmpref,location^.register);
              LOC_REFERENCE:
                begin
                  reference_reset_base(ref,location^.reference.index,location^.reference.offset,ctempposinvalid,paraloc.alignment,[]);
                  { doubles in softemu mode have a strange order of registers and references }
                  if location^.size=OS_32 then
                    g_concatcopy(list,tmpref,ref,4)
                  else
                    begin
                      g_concatcopy(list,tmpref,ref,sizeleft);
                      if assigned(location^.next) then
                        internalerror(2005010710);
                    end;
                end;
              LOC_VOID:
                begin
                  // nothing to do
                end;
              else
                internalerror(2002081103);
            end;
            inc(tmpref.offset,tcgsize2size[location^.size]);
            dec(sizeleft,tcgsize2size[location^.size]);
            location := location^.next;
          end;
      end;


    procedure tcgz80.a_loadaddr_ref_cgpara(list : TAsmList;const r : treference;const paraloc : TCGPara);
      var
        tmpreg: tregister;
      begin
        tmpreg:=getaddressregister(list);
        a_loadaddr_ref_reg(list,r,tmpreg);
        a_load_reg_cgpara(list,OS_ADDR,tmpreg,paraloc);
      end;


    procedure tcgz80.a_call_name(list : TAsmList;const s : string; weak: boolean);
      var
        sym: TAsmSymbol;
      begin
        if weak then
          sym:=current_asmdata.WeakRefAsmSymbol(s,AT_FUNCTION)
        else
          sym:=current_asmdata.RefAsmSymbol(s,AT_FUNCTION);

        list.concat(taicpu.op_sym(A_CALL,sym));

        include(current_procinfo.flags,pi_do_call);
      end;


    procedure tcgz80.a_call_reg(list : TAsmList;reg: tregister);
      var
        l : TAsmLabel;
        ref : treference;
      begin
        current_asmdata.getjumplabel(l);
        reference_reset(ref,0,[]);
        ref.symbol:=l;
        list.concat(taicpu.op_ref_reg(A_LD,ref,reg));
        list.concat(tai_const.Create_8bit($CD));
        list.concat(tai_label.Create(l));
        include(current_procinfo.flags,pi_do_call);
      end;


     procedure tcgz80.a_op_const_reg(list : TAsmList; Op: TOpCG; size: TCGSize; a: tcgint; reg: TRegister);
       begin
         if not(size in [OS_S8,OS_8,OS_S16,OS_16,OS_S32,OS_32]) then
           internalerror(2012102403);
         a_op_const_reg_internal(list,Op,size,a,reg,NR_NO);
       end;


     procedure tcgz80.a_op_reg_reg(list: TAsmList; Op: TOpCG; size: TCGSize; src, dst : TRegister);
       begin
         if not(size in [OS_S8,OS_8,OS_S16,OS_16,OS_S32,OS_32]) then
           internalerror(2012102401);
         a_op_reg_reg_internal(list,Op,size,src,NR_NO,dst,NR_NO);
       end;


     procedure tcgz80.a_op_reg_reg_internal(list : TAsmList; Op: TOpCG; size: TCGSize; src, srchi, dst, dsthi: TRegister);
       var
         countreg,
         tmpreg: tregister;
         i : integer;
         instr : taicpu;
         paraloc1,paraloc2,paraloc3 : TCGPara;
         l1,l2 : tasmlabel;
         pd : tprocdef;

       procedure NextSrcDst;
         begin
           if i=5 then
             begin
               dst:=dsthi;
               src:=srchi;
             end
           else
             begin
               dst:=GetNextReg(dst);
               src:=GetNextReg(src);
             end;
         end;

       { iterates TmpReg through all registers of dst }
       procedure NextTmp;
         begin
           if i=5 then
             tmpreg:=dsthi
           else
             tmpreg:=GetNextReg(tmpreg);
         end;

      begin
         case op of
           OP_ADD:
             begin
               list.concat(taicpu.op_reg_reg(A_ADD,dst,src));
               if size in [OS_S16,OS_16,OS_S32,OS_32,OS_S64,OS_64] then
                 begin
                   for i:=2 to tcgsize2size[size] do
                     begin
                       NextSrcDst;
                       list.concat(taicpu.op_reg_reg(A_ADC,dst,src));
                     end;
                 end;
             end;

           OP_SUB:
             begin
               list.concat(taicpu.op_reg_reg(A_SUB,dst,src));
               if size in [OS_S16,OS_16,OS_S32,OS_32,OS_S64,OS_64] then
                 begin
                   for i:=2 to tcgsize2size[size] do
                     begin
                       NextSrcDst;
                       list.concat(taicpu.op_reg_reg(A_SBC,dst,src));
                     end;
                 end;
             end;

           OP_NEG:
             begin
               if src<>dst then
                 begin
                   if size in [OS_S64,OS_64] then
                     begin
                       a_load_reg_reg(list,OS_32,OS_32,src,dst);
                       a_load_reg_reg(list,OS_32,OS_32,srchi,dsthi);
                     end
                   else
                     a_load_reg_reg(list,size,size,src,dst);
                 end;

               if size in [OS_S16,OS_16,OS_S32,OS_32,OS_S64,OS_64] then
                 begin
                   tmpreg:=GetNextReg(dst);
                   for i:=2 to tcgsize2size[size] do
                     begin
                       list.concat(taicpu.op_reg(A_CPL,tmpreg));
                       NextTmp;
                     end;
                   list.concat(taicpu.op_reg(A_NEG,dst));
                   tmpreg:=GetNextReg(dst);
                   for i:=2 to tcgsize2size[size] do
                     begin
                       list.concat(taicpu.op_reg_const(A_SBC,tmpreg,-1));
                       NextTmp;
                   end;
                 end;
             end;

           OP_NOT:
             begin
               for i:=1 to tcgsize2size[size] do
                 begin
                   if src<>dst then
                     a_load_reg_reg(list,OS_8,OS_8,src,dst);
                   list.concat(taicpu.op_reg(A_CPL,dst));
                   NextSrcDst;
                 end;
             end;

           OP_MUL,OP_IMUL:
             { special stuff, needs separate handling inside code
               generator                                          }
             internalerror(2017032604);

           OP_DIV,OP_IDIV:
             { special stuff, needs separate handling inside code
               generator                                          }
             internalerror(2017032604);

           OP_SHR,OP_SHL,OP_SAR,OP_ROL,OP_ROR:
             begin
               //current_asmdata.getjumplabel(l1);
               //current_asmdata.getjumplabel(l2);
               //countreg:=getintregister(list,OS_8);
               //a_load_reg_reg(list,size,OS_8,src,countreg);
               //list.concat(taicpu.op_reg(A_TST,countreg));
               //a_jmp_flags(list,F_EQ,l2);
               //cg.a_label(list,l1);
               //case op of
               //  OP_SHR:
               //    list.concat(taicpu.op_reg(A_LSR,GetOffsetReg64(dst,dsthi,tcgsize2size[size]-1)));
               //  OP_SHL:
               //    list.concat(taicpu.op_reg(A_LSL,dst));
               //  OP_SAR:
               //    list.concat(taicpu.op_reg(A_ASR,GetOffsetReg64(dst,dsthi,tcgsize2size[size]-1)));
               //  OP_ROR:
               //    begin
               //      { load carry? }
               //      if not(size in [OS_8,OS_S8]) then
               //        begin
               //          list.concat(taicpu.op_none(A_CLC));
               //          list.concat(taicpu.op_reg_const(A_SBRC,src,0));
               //          list.concat(taicpu.op_none(A_SEC));
               //        end;
               //      list.concat(taicpu.op_reg(A_ROR,GetOffsetReg64(dst,dsthi,tcgsize2size[size]-1)));
               //    end;
               //  OP_ROL:
               //    begin
               //      { load carry? }
               //      if not(size in [OS_8,OS_S8]) then
               //        begin
               //          list.concat(taicpu.op_none(A_CLC));
               //          list.concat(taicpu.op_reg_const(A_SBRC,GetOffsetReg64(dst,dsthi,tcgsize2size[size]-1),7));
               //          list.concat(taicpu.op_none(A_SEC));
               //        end;
               //      list.concat(taicpu.op_reg(A_ROL,dst))
               //    end;
               //  else
               //    internalerror(2011030901);
               //end;
               //if size in [OS_S16,OS_16,OS_S32,OS_32,OS_S64,OS_64] then
               //  begin
               //    for i:=2 to tcgsize2size[size] do
               //      begin
               //        case op of
               //          OP_ROR,
               //          OP_SHR:
               //            list.concat(taicpu.op_reg(A_ROR,GetOffsetReg64(dst,dsthi,tcgsize2size[size]-i)));
               //          OP_ROL,
               //          OP_SHL:
               //            list.concat(taicpu.op_reg(A_ROL,GetOffsetReg64(dst,dsthi,i-1)));
               //          OP_SAR:
               //            list.concat(taicpu.op_reg(A_ROR,GetOffsetReg64(dst,dsthi,tcgsize2size[size]-i)));
               //          else
               //            internalerror(2011030902);
               //        end;
               //    end;
               //  end;
               //
               //list.concat(taicpu.op_reg(A_DEC,countreg));
               //a_jmp_flags(list,F_NE,l1);
               //// keep registers alive
               //list.concat(taicpu.op_reg_reg(A_MOV,countreg,countreg));
               //cg.a_label(list,l2);
             end;

           OP_AND,OP_OR,OP_XOR:
             begin
                for i:=1 to tcgsize2size[size] do
                  begin
                    list.concat(taicpu.op_reg_reg(topcg2asmop[op],dst,src));
                    NextSrcDst;
                  end;
             end;
           else
             internalerror(2011022004);
         end;
       end;

     procedure tcgz80.a_op_const_reg_internal(list: TAsmList; Op: TOpCG;
      size: TCGSize; a: tcgint; reg, reghi: TRegister);

       var
         mask : qword;
         shift : byte;
         i,j : byte;
         tmpreg : tregister;
         tmpreg64 : tregister64;

      procedure NextReg;
        begin
          if i=5 then
            reg:=reghi
          else
            reg:=GetNextReg(reg);
        end;

      var
        curvalue : byte;

       begin
         optimize_op_const(size,op,a);
         mask:=$ff;
         shift:=0;
         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_OR:
             begin
               //for i:=1 to tcgsize2size[size] do
               //  begin
               //    if ((qword(a) and mask) shr shift)<>0 then
               //      list.concat(taicpu.op_reg_const(A_ORI,reg,(qword(a) and mask) shr shift));
               //    NextReg;
               //    mask:=mask shl 8;
               //    inc(shift,8);
               //  end;
             end;
           OP_AND:
             begin
               //for i:=1 to tcgsize2size[size] do
               //  begin
               //    if ((qword(a) and mask) shr shift)=0 then
               //      list.concat(taicpu.op_reg_reg(A_MOV,reg,NR_R1))
               //    else
               //      list.concat(taicpu.op_reg_const(A_ANDI,reg,(qword(a) and mask) shr shift));
               //    NextReg;
               //    mask:=mask shl 8;
               //    inc(shift,8);
               //  end;
             end;
           OP_SUB:
             begin
               //if ((a and mask)=1) and (tcgsize2size[size]=1) then
               //  list.concat(taicpu.op_reg(A_DEC,reg))
               //else
               //  list.concat(taicpu.op_reg_const(A_SUBI,reg,a and mask));
               //if size in [OS_S16,OS_16,OS_S32,OS_32,OS_S64,OS_64] then
               //  begin
               //    for i:=2 to tcgsize2size[size] do
               //      begin
               //        NextReg;
               //        mask:=mask shl 8;
               //        inc(shift,8);
               //        curvalue:=(qword(a) and mask) shr shift;
               //        { decrease pressure on upper half of registers by using SBC ...,R1 instead
               //          of SBCI ...,0 }
               //        if curvalue=0 then
               //          list.concat(taicpu.op_reg_reg(A_SBC,reg,NR_R1))
               //        else
               //          list.concat(taicpu.op_reg_const(A_SBCI,reg,curvalue));
               //      end;
               //  end;
             end;
           OP_SHR,OP_SHL,OP_SAR,OP_ROL,OP_ROR:
             begin
               //if a*tcgsize2size[size]<=8 then
               //  begin
               //    for j:=1 to a do
               //      begin
               //        case op of
               //          OP_SHR:
               //            list.concat(taicpu.op_reg(A_LSR,GetOffsetReg64(reg,reghi,tcgsize2size[size]-1)));
               //          OP_SHL:
               //            list.concat(taicpu.op_reg(A_LSL,reg));
               //          OP_SAR:
               //            list.concat(taicpu.op_reg(A_ASR,GetOffsetReg64(reg,reghi,tcgsize2size[size]-1)));
               //          OP_ROR:
               //            begin
               //              { load carry? }
               //              if not(size in [OS_8,OS_S8]) then
               //                begin
               //                  list.concat(taicpu.op_none(A_CLC));
               //                  list.concat(taicpu.op_reg_const(A_SBRC,reg,0));
               //                  list.concat(taicpu.op_none(A_SEC));
               //                end;
               //              list.concat(taicpu.op_reg(A_ROR,GetOffsetReg64(reg,reghi,tcgsize2size[size]-1)));
               //            end;
               //          OP_ROL:
               //            begin
               //              { load carry? }
               //              if not(size in [OS_8,OS_S8]) then
               //                begin
               //                  list.concat(taicpu.op_none(A_CLC));
               //                  list.concat(taicpu.op_reg_const(A_SBRC,GetOffsetReg64(reg,reghi,tcgsize2size[size]-1),7));
               //                  list.concat(taicpu.op_none(A_SEC));
               //                end;
               //              list.concat(taicpu.op_reg(A_ROL,reg))
               //            end;
               //          else
               //            internalerror(2011030901);
               //        end;
               //        if size in [OS_S16,OS_16,OS_S32,OS_32,OS_S64,OS_64] then
               //          begin
               //            for i:=2 to tcgsize2size[size] do
               //              begin
               //                case op of
               //                  OP_ROR,
               //                  OP_SHR:
               //                    list.concat(taicpu.op_reg(A_ROR,GetOffsetReg64(reg,reghi,tcgsize2size[size]-i)));
               //                  OP_ROL,
               //                  OP_SHL:
               //                    list.concat(taicpu.op_reg(A_ROL,GetOffsetReg64(reg,reghi,i-1)));
               //                  OP_SAR:
               //                    list.concat(taicpu.op_reg(A_ROR,GetOffsetReg64(reg,reghi,tcgsize2size[size]-i)));
               //                  else
               //                    internalerror(2011030902);
               //                end;
               //            end;
               //          end;
               //    end;
               //  end
               //else
               //  begin
               //    tmpreg:=getintregister(list,size);
               //    a_load_const_reg(list,size,a,tmpreg);
               //    a_op_reg_reg(list,op,size,tmpreg,reg);
               //  end;
             end;
           OP_ADD:
             begin
               //curvalue:=a and mask;
               //if curvalue=0 then
               //  list.concat(taicpu.op_reg_reg(A_ADD,reg,NR_R1))
               //else if (curvalue=1) and (tcgsize2size[size]=1) then
               //  list.concat(taicpu.op_reg(A_INC,reg))
               //else
               //  begin
               //    tmpreg:=getintregister(list,OS_8);
               //    a_load_const_reg(list,OS_8,curvalue,tmpreg);
               //    list.concat(taicpu.op_reg_reg(A_ADD,reg,tmpreg));
               //  end;
               //if size in [OS_S16,OS_16,OS_S32,OS_32,OS_S64,OS_64] then
               //  begin
               //    for i:=2 to tcgsize2size[size] do
               //      begin
               //        NextReg;
               //        mask:=mask shl 8;
               //        inc(shift,8);
               //        curvalue:=(qword(a) and mask) shr shift;
               //        { decrease pressure on upper half of registers by using ADC ...,R1 instead
               //          of ADD ...,0 }
               //        if curvalue=0 then
               //          list.concat(taicpu.op_reg_reg(A_ADC,reg,NR_R1))
               //        else
               //          begin
               //            tmpreg:=getintregister(list,OS_8);
               //            a_load_const_reg(list,OS_8,curvalue,tmpreg);
               //            list.concat(taicpu.op_reg_reg(A_ADC,reg,tmpreg));
               //          end;
               //      end;
               //  end;
             end;
         else
           begin
             if size in [OS_64,OS_S64] then
               begin
                 tmpreg64.reglo:=getintregister(list,OS_32);
                 tmpreg64.reghi:=getintregister(list,OS_32);
                 cg64.a_load64_const_reg(list,a,tmpreg64);
                 cg64.a_op64_reg_reg(list,op,size,tmpreg64,joinreg64(reg,reghi));
               end
             else
               begin
{$if 0}
                 { code not working yet }
                 if (op=OP_SAR) and (a=31) and (size in [OS_32,OS_S32]) then
                   begin
                     tmpreg:=reg;
                     for i:=1 to 4 do
                       begin
                         list.concat(taicpu.op_reg_reg(A_MOV,tmpreg,NR_R1));
                         tmpreg:=GetNextReg(tmpreg);
                       end;
                   end
                 else
{$endif}
                   begin
                     tmpreg:=getintregister(list,size);
                     a_load_const_reg(list,size,a,tmpreg);
                     a_op_reg_reg(list,op,size,tmpreg,reg);
                   end;
               end;
           end;
       end;
     end;


     procedure tcgz80.a_load_const_reg(list : TAsmList; size: tcgsize; a : tcgint;reg : tregister);
       var
         mask : qword;
         shift : byte;
         i : byte;
       begin
         mask:=$ff;
         shift:=0;
         for i:=tcgsize2size[size] downto 1 do
           begin
             list.Concat(taicpu.op_reg_const(A_LD,reg,(qword(a) and mask) shr shift));
             if i<>1 then
               begin
                 mask:=mask shl 8;
                 inc(shift,8);
                 reg:=GetNextReg(reg);
               end;
           end;
       end;


    procedure tcgz80.maybegetcpuregister(list:tasmlist;reg : tregister);
      begin
        { allocate the register only, if a cpu register is passed }
        if getsupreg(reg)<first_int_imreg then
          getcpuregister(list,reg);
      end;


    function tcgz80.normalize_ref(list:TAsmList;ref: treference;tmpreg : tregister) : treference;

      var
        tmpref : treference;
        l : tasmlabel;
      begin
        Result:=ref;
//
//         if ref.addressmode<>AM_UNCHANGED then
//           internalerror(2011021701);
//
//        { Be sure to have a base register }
//        if (ref.base=NR_NO) then
//          begin
//            { only symbol+offset? }
//            if ref.index=NR_NO then
//              exit;
//            ref.base:=ref.index;
//            ref.index:=NR_NO;
//          end;
//
//        { can we take advantage of adiw/sbiw? }
//        if (current_settings.cputype>=cpu_avr2) and not(assigned(ref.symbol)) and (ref.offset<>0) and (ref.offset>=-63) and (ref.offset<=63) and
//          ((tmpreg=NR_R24) or (tmpreg=NR_R26) or (tmpreg=NR_R28) or (tmpreg=NR_R30)) and (ref.base<>NR_NO) then
//          begin
//            maybegetcpuregister(list,tmpreg);
//            emit_mov(list,tmpreg,ref.base);
//            maybegetcpuregister(list,GetNextReg(tmpreg));
//            emit_mov(list,GetNextReg(tmpreg),GetNextReg(ref.base));
//            if ref.index<>NR_NO then
//              begin
//                list.concat(taicpu.op_reg_reg(A_ADD,tmpreg,ref.index));
//                list.concat(taicpu.op_reg_reg(A_ADC,GetNextReg(tmpreg),GetNextReg(ref.index)));
//              end;
//            if ref.offset>0 then
//              list.concat(taicpu.op_reg_const(A_ADIW,tmpreg,ref.offset))
//            else
//              list.concat(taicpu.op_reg_const(A_SBIW,tmpreg,-ref.offset));
//            ref.offset:=0;
//            ref.base:=tmpreg;
//            ref.index:=NR_NO;
//          end
//        else if assigned(ref.symbol) or (ref.offset<>0) then
//          begin
//            reference_reset(tmpref,0,[]);
//            tmpref.symbol:=ref.symbol;
//            tmpref.offset:=ref.offset;
//            if assigned(ref.symbol) and (ref.symbol.typ in [AT_FUNCTION,AT_LABEL]) then
//              tmpref.refaddr:=addr_lo8_gs
//            else
//              tmpref.refaddr:=addr_lo8;
//            maybegetcpuregister(list,tmpreg);
//            list.concat(taicpu.op_reg_ref(A_LDI,tmpreg,tmpref));
//
//            if assigned(ref.symbol) and (ref.symbol.typ in [AT_FUNCTION,AT_LABEL]) then
//              tmpref.refaddr:=addr_hi8_gs
//            else
//              tmpref.refaddr:=addr_hi8;
//            maybegetcpuregister(list,GetNextReg(tmpreg));
//            list.concat(taicpu.op_reg_ref(A_LDI,GetNextReg(tmpreg),tmpref));
//
//            if (ref.base<>NR_NO) then
//              begin
//                list.concat(taicpu.op_reg_reg(A_ADD,tmpreg,ref.base));
//                list.concat(taicpu.op_reg_reg(A_ADC,GetNextReg(tmpreg),GetNextReg(ref.base)));
//              end;
//            if (ref.index<>NR_NO) then
//              begin
//                list.concat(taicpu.op_reg_reg(A_ADD,tmpreg,ref.index));
//                list.concat(taicpu.op_reg_reg(A_ADC,GetNextReg(tmpreg),GetNextReg(ref.index)));
//              end;
//            ref.symbol:=nil;
//            ref.offset:=0;
//            ref.base:=tmpreg;
//            ref.index:=NR_NO;
//          end
//        else if (ref.base<>NR_NO) and (ref.index<>NR_NO) then
//          begin
//            maybegetcpuregister(list,tmpreg);
//            emit_mov(list,tmpreg,ref.base);
//            maybegetcpuregister(list,GetNextReg(tmpreg));
//            emit_mov(list,GetNextReg(tmpreg),GetNextReg(ref.base));
//            list.concat(taicpu.op_reg_reg(A_ADD,tmpreg,ref.index));
//            list.concat(taicpu.op_reg_reg(A_ADC,GetNextReg(tmpreg),GetNextReg(ref.index)));
//            ref.base:=tmpreg;
//            ref.index:=NR_NO;
//          end
//        else if (ref.base<>NR_NO) then
//          begin
//            maybegetcpuregister(list,tmpreg);
//            emit_mov(list,tmpreg,ref.base);
//            maybegetcpuregister(list,GetNextReg(tmpreg));
//            emit_mov(list,GetNextReg(tmpreg),GetNextReg(ref.base));
//            ref.base:=tmpreg;
//            ref.index:=NR_NO;
//          end
//        else if (ref.index<>NR_NO) then
//          begin
//            maybegetcpuregister(list,tmpreg);
//            emit_mov(list,tmpreg,ref.index);
//            maybegetcpuregister(list,GetNextReg(tmpreg));
//            emit_mov(list,GetNextReg(tmpreg),GetNextReg(ref.index));
//            ref.base:=tmpreg;
//            ref.index:=NR_NO;
//          end;
        Result:=ref;
      end;


     procedure tcgz80.a_load_reg_ref(list : TAsmList; fromsize, tosize: tcgsize; reg : tregister;const ref : treference);
       var
         href : treference;
         i : integer;
       begin
         href:=Ref;
         { ensure, href.base contains a valid register if there is any register used }
         if href.base=NR_NO then
           begin
             href.base:=href.index;
             href.index:=NR_NO;
           end;

         if (tcgsize2size[fromsize]>32) or (tcgsize2size[tosize]>32) or (fromsize=OS_NO) or (tosize=OS_NO) then
           internalerror(2011021307);

         if fromsize=tosize then
           begin
             getcpuregister(list,NR_A);
             for i:=tcgsize2size[fromsize] downto 1 do
             begin
               a_load_reg_reg(list,OS_8,OS_8,reg,NR_A);
               list.concat(taicpu.op_ref_reg(A_LD,href,NR_A));
               if i<>1 then
                 begin
                   inc(href.offset);
                   reg:=GetNextReg(reg);
                 end;
             end;
             ungetcpuregister(list,NR_A);
           end
         else
           list.Concat(tai_comment.Create(strpnew('WARNING! not implemented: a_load_reg_ref')));
       end;


     procedure tcgz80.a_load_ref_reg(list : TAsmList; fromsize, tosize : tcgsize;
       const Ref : treference;reg : tregister);
       var
         href : treference;
         i : integer;
       begin
         href:=Ref;
         { ensure, href.base contains a valid register if there is any register used }
         if href.base=NR_NO then
           begin
             href.base:=href.index;
             href.index:=NR_NO;
           end;

         if (tcgsize2size[fromsize]>32) or (tcgsize2size[tosize]>32) or (fromsize=OS_NO) or (tosize=OS_NO) then
           internalerror(2011021307);

         if tosize=fromsize then
           begin
             getcpuregister(list,NR_A);
             for i:=tcgsize2size[fromsize] downto 1 do
               begin
                 list.concat(taicpu.op_reg_ref(A_LD,NR_A,href));
                 a_load_reg_reg(list,OS_8,OS_8,NR_A,reg);

                 if i<>1 then
                   begin
                     inc(href.offset);
                     reg:=GetNextReg(reg);
                   end;
               end;
             ungetcpuregister(list,NR_A);
           end
         else
           list.Concat(tai_comment.Create(strpnew('WARNING! not implemented: a_load_ref_reg')));

         //conv_done:=false;
         //if tosize<>fromsize then
         //  begin
         //    conv_done:=true;
         //    if tcgsize2size[tosize]<=tcgsize2size[fromsize] then
         //      fromsize:=tosize;
         //    case fromsize of
         //      OS_8:
         //        begin
         //          list.concat(taicpu.op_reg_ref(GetLoad(href),reg,href));
         //          for i:=2 to tcgsize2size[tosize] do
         //            begin
         //              reg:=GetNextReg(reg);
         //              emit_mov(list,reg,NR_R1);
         //            end;
         //        end;
         //      OS_S8:
         //        begin
         //          list.concat(taicpu.op_reg_ref(GetLoad(href),reg,href));
         //          tmpreg:=reg;
         //
         //          if tcgsize2size[tosize]>1 then
         //            begin
         //              reg:=GetNextReg(reg);
         //              emit_mov(list,reg,NR_R1);
         //              list.concat(taicpu.op_reg_const(A_SBRC,tmpreg,7));
         //              list.concat(taicpu.op_reg(A_COM,reg));
         //              tmpreg:=reg;
         //              for i:=3 to tcgsize2size[tosize] do
         //                begin
         //                  reg:=GetNextReg(reg);
         //                  emit_mov(list,reg,tmpreg);
         //                end;
         //            end;
         //        end;
         //      OS_16:
         //        begin
         //          if not(QuickRef) then
         //            href.addressmode:=AM_POSTINCREMENT;
         //          list.concat(taicpu.op_reg_ref(GetLoad(href),reg,href));
         //
         //          if QuickRef then
         //            inc(href.offset);
         //          href.addressmode:=AM_UNCHANGED;
         //
         //          reg:=GetNextReg(reg);
         //          list.concat(taicpu.op_reg_ref(GetLoad(href),reg,href));
         //
         //          for i:=3 to tcgsize2size[tosize] do
         //            begin
         //              reg:=GetNextReg(reg);
         //              emit_mov(list,reg,NR_R1);
         //            end;
         //        end;
         //      OS_S16:
         //        begin
         //          if not(QuickRef) then
         //            href.addressmode:=AM_POSTINCREMENT;
         //          list.concat(taicpu.op_reg_ref(GetLoad(href),reg,href));
         //          if QuickRef then
         //            inc(href.offset);
         //          href.addressmode:=AM_UNCHANGED;
         //
         //          reg:=GetNextReg(reg);
         //          list.concat(taicpu.op_reg_ref(GetLoad(href),reg,href));
         //          tmpreg:=reg;
         //
         //          reg:=GetNextReg(reg);
         //          emit_mov(list,reg,NR_R1);
         //          list.concat(taicpu.op_reg_const(A_SBRC,tmpreg,7));
         //          list.concat(taicpu.op_reg(A_COM,reg));
         //          tmpreg:=reg;
         //          for i:=4 to tcgsize2size[tosize] do
         //            begin
         //              reg:=GetNextReg(reg);
         //              emit_mov(list,reg,tmpreg);
         //            end;
         //        end;
         //      else
         //        conv_done:=false;
         //    end;
         //  end;
         //if not conv_done then
         //  begin
         //    for i:=1 to tcgsize2size[fromsize] do
         //      begin
         //        if not(QuickRef) and (i<tcgsize2size[fromsize]) then
         //          href.addressmode:=AM_POSTINCREMENT
         //        else
         //          href.addressmode:=AM_UNCHANGED;
         //
         //        list.concat(taicpu.op_reg_ref(GetLoad(href),reg,href));
         //
         //        if QuickRef then
         //          inc(href.offset);
         //
         //        reg:=GetNextReg(reg);
         //      end;
         //  end;
         //
         //if not(QuickRef) then
         //  begin
         //    ungetcpuregister(list,href.base);
         //    ungetcpuregister(list,GetNextReg(href.base));
         //  end;
       end;


     procedure tcgz80.a_load_reg_reg(list : TAsmList; fromsize, tosize : tcgsize;reg1,reg2 : tregister);
       var
         conv_done: boolean;
         tmpreg : tregister;
         i : integer;
       begin
         if (tcgsize2size[fromsize]>32) or (tcgsize2size[tosize]>32) or (fromsize=OS_NO) or (tosize=OS_NO) then
           internalerror(2011021310);

         if tosize=fromsize then
           begin
             if reg1<>reg2 then
               for i:=tcgsize2size[fromsize] downto 1 do
                 begin
                   emit_mov(list,reg2,reg1);
                   if i<>1 then
                     begin
                       reg1:=GetNextReg(reg1);
                       reg2:=GetNextReg(reg2);
                     end;
                 end;
           end
         else
           list.Concat(tai_comment.Create(strpnew('WARNING! not implemented: a_load_reg_reg')));
       end;


     procedure tcgz80.a_loadfpu_reg_reg(list: TAsmList; fromsize,tosize: tcgsize; reg1, reg2: tregister);
       begin
         internalerror(2012010702);
       end;


     procedure tcgz80.a_loadfpu_ref_reg(list: TAsmList; fromsize,tosize: tcgsize; const ref: treference; reg: tregister);
       begin
         internalerror(2012010703);
       end;


     procedure tcgz80.a_loadfpu_reg_ref(list: TAsmList; fromsize, tosize: tcgsize; reg: tregister; const ref: treference);
       begin
         internalerror(2012010704);
       end;


    {  comparison operations }
    procedure tcgz80.a_cmp_const_reg_label(list : TAsmList;size : tcgsize;
      cmp_op : topcmp;a : tcgint;reg : tregister;l : tasmlabel);
      var
        swapped : boolean;
        tmpreg : tregister;
        i : byte;
      begin
        list.Concat(tai_comment.Create(strpnew('WARNING! not implemented: a_cmp_const_reg_label')));
        //if a=0 then
        //  begin
        //    swapped:=false;
        //    { swap parameters? }
        //    case cmp_op of
        //      OC_GT:
        //        begin
        //          swapped:=true;
        //          cmp_op:=OC_LT;
        //        end;
        //      OC_LTE:
        //        begin
        //          swapped:=true;
        //          cmp_op:=OC_GTE;
        //        end;
        //      OC_BE:
        //        begin
        //          swapped:=true;
        //          cmp_op:=OC_AE;
        //        end;
        //      OC_A:
        //        begin
        //          swapped:=true;
        //          cmp_op:=OC_B;
        //        end;
        //    end;
        //
        //    if swapped then
        //      list.concat(taicpu.op_reg_reg(A_CP,NR_R1,reg))
        //    else
        //      list.concat(taicpu.op_reg_reg(A_CP,reg,NR_R1));
        //
        //    for i:=2 to tcgsize2size[size] do
        //      begin
        //        reg:=GetNextReg(reg);
        //        if swapped then
        //          list.concat(taicpu.op_reg_reg(A_CPC,NR_R1,reg))
        //        else
        //          list.concat(taicpu.op_reg_reg(A_CPC,reg,NR_R1));
        //      end;
        //
        //    a_jmp_cond(list,cmp_op,l);
        //  end
        //else
        //  inherited a_cmp_const_reg_label(list,size,cmp_op,a,reg,l);
      end;


    procedure tcgz80.a_cmp_reg_reg_label(list : TAsmList;size : tcgsize;
      cmp_op : topcmp;reg1,reg2 : tregister;l : tasmlabel);
      var
        swapped : boolean;
        tmpreg : tregister;
        i : byte;
      begin
        list.Concat(tai_comment.Create(strpnew('WARNING! not implemented: a_cmp_reg_reg_label')));
        //swapped:=false;
        //{ swap parameters? }
        //case cmp_op of
        //  OC_GT:
        //    begin
        //      swapped:=true;
        //      cmp_op:=OC_LT;
        //    end;
        //  OC_LTE:
        //    begin
        //      swapped:=true;
        //      cmp_op:=OC_GTE;
        //    end;
        //  OC_BE:
        //    begin
        //      swapped:=true;
        //      cmp_op:=OC_AE;
        //    end;
        //  OC_A:
        //    begin
        //      swapped:=true;
        //      cmp_op:=OC_B;
        //    end;
        //end;
        //if swapped then
        //  begin
        //    tmpreg:=reg1;
        //    reg1:=reg2;
        //    reg2:=tmpreg;
        //  end;
        //list.concat(taicpu.op_reg_reg(A_CP,reg2,reg1));
        //
        //for i:=2 to tcgsize2size[size] do
        //  begin
        //    reg1:=GetNextReg(reg1);
        //    reg2:=GetNextReg(reg2);
        //    list.concat(taicpu.op_reg_reg(A_CPC,reg2,reg1));
        //  end;
        //
        //a_jmp_cond(list,cmp_op,l);
      end;


    procedure tcgz80.a_jmp_name(list : TAsmList;const s : string);
      var
        ai : taicpu;
      begin
        ai:=taicpu.op_sym(A_JP,current_asmdata.RefAsmSymbol(s,AT_FUNCTION));
        ai.is_jmp:=true;
        list.concat(ai);
      end;


    procedure tcgz80.a_jmp_always(list : TAsmList;l: tasmlabel);
      var
        ai : taicpu;
      begin
        ai:=taicpu.op_sym(A_JP,l);
        ai.is_jmp:=true;
        list.concat(ai);
      end;


    procedure tcgz80.a_jmp_flags(list : TAsmList;const f : TResFlags;l: tasmlabel);
      var
        ai : taicpu;
      begin
        list.Concat(tai_comment.Create(strpnew('WARNING! not implemented: a_jmp_flags')));
//        ai:=setcondition(taicpu.op_sym(A_BRxx,l),flags_to_cond(f));
        ai.is_jmp:=true;
        list.concat(ai);
      end;


    procedure tcgz80.g_flags2reg(list: TAsmList; size: TCgSize; const f: TResFlags; reg: TRegister);
      var
        l : TAsmLabel;
        tmpflags : TResFlags;
      begin
        list.Concat(tai_comment.Create(strpnew('WARNING! not implemented: g_flags2reg')));
        current_asmdata.getjumplabel(l);
        {
        if flags_to_cond(f) then
          begin
            tmpflags:=f;
            inverse_flags(tmpflags);
            emit_mov(reg,NR_R1);
            a_jmp_flags(list,tmpflags,l);
            list.concat(taicpu.op_reg_const(A_LDI,reg,1));
          end
        else
        }
          begin
            //list.concat(taicpu.op_reg_const(A_LDI,reg,1));
            //a_jmp_flags(list,f,l);
            //emit_mov(list,reg,NR_R1);
          end;
        cg.a_label(list,l);
      end;


    procedure tcgz80.a_adjust_sp(list : TAsmList; value : longint);
      var
        i : integer;
      begin
        //case value of
        //  0:
        //    ;
        //  {-14..-1:
        //    begin
        //      if ((-value) mod 2)<>0 then
        //        list.concat(taicpu.op_reg(A_PUSH,NR_R0));
        //      for i:=1 to (-value) div 2 do
        //        list.concat(taicpu.op_const(A_RCALL,0));
        //    end;
        //  1..7:
        //    begin
        //      for i:=1 to value do
        //        list.concat(taicpu.op_reg(A_POP,NR_R0));
        //    end;}
        //  else
        //    begin
        //      list.concat(taicpu.op_reg_const(A_SUBI,NR_R28,lo(word(-value))));
        //      list.concat(taicpu.op_reg_const(A_SBCI,NR_R29,hi(word(-value))));
        //      // get SREG
        //      list.concat(taicpu.op_reg_const(A_IN,NR_R0,NIO_SREG));
        //
        //      // block interrupts
        //      list.concat(taicpu.op_none(A_CLI));
        //
        //      // write high SP
        //      list.concat(taicpu.op_const_reg(A_OUT,NIO_SP_HI,NR_R29));
        //
        //      // release interrupts
        //      list.concat(taicpu.op_const_reg(A_OUT,NIO_SREG,NR_R0));
        //
        //      // write low SP
        //      list.concat(taicpu.op_const_reg(A_OUT,NIO_SP_LO,NR_R28));
        //    end;
        //end;
      end;


    function tcgz80.GetLoad(const ref: treference) : tasmop;
      begin
        //if (ref.base=NR_NO) and (ref.index=NR_NO) then
        //  result:=A_LDS
        //else if (ref.base<>NR_NO) and (ref.offset<>0) then
        //  result:=A_LDD
        //else
        //  result:=A_LD;
      end;


    function tcgz80.GetStore(const ref: treference) : tasmop;
      begin
        //if (ref.base=NR_NO) and (ref.index=NR_NO) then
        //  result:=A_STS
        //else if (ref.base<>NR_NO) and (ref.offset<>0) then
        //  result:=A_STD
        //else
        //  result:=A_ST;
      end;


    procedure tcgz80.g_proc_entry(list : TAsmList;localsize : longint;nostackframe:boolean);
      var
         regs : tcpuregisterset;
         reg : tsuperregister;
      begin
        //if po_interrupt in current_procinfo.procdef.procoptions then
        //  begin
        //    { check if the framepointer is actually used, this is done here because
        //      we have to know the size of the locals (must be 0), avr does not know
        //      an sp based stack }
        //
        //    if not(current_procinfo.procdef.stack_tainting_parameter(calleeside)) and
        //      (localsize=0) then
        //      current_procinfo.framepointer:=NR_NO;
        //
        //    { save int registers,
        //      but only if the procedure returns }
        //    if not(po_noreturn in current_procinfo.procdef.procoptions) then
        //      regs:=rg[R_INTREGISTER].used_in_proc
        //    else
        //      regs:=[];
        //    { if the framepointer is potentially used, save it always because we need a proper stack frame,
        //      even if the procedure never returns, the procedure could be e.g. a nested one accessing
        //      an outer stackframe }
        //    if current_procinfo.framepointer<>NR_NO then
        //      regs:=regs+[RS_R28,RS_R29];
        //
        //    regs:=regs+[RS_R0];
        //
        //    for reg:=RS_R31 downto RS_R0 do
        //      if reg in regs then
        //        list.concat(taicpu.op_reg(A_PUSH,newreg(R_INTREGISTER,reg,R_SUBWHOLE)));
        //
        //    { Save SREG }
        //    list.concat(taicpu.op_reg_const(A_IN, NR_R0, $3F));
        //    list.concat(taicpu.op_reg(A_PUSH, NR_R0));
        //
        //    if current_procinfo.framepointer<>NR_NO then
        //      begin
        //        list.concat(taicpu.op_reg_const(A_IN,NR_R28,NIO_SP_LO));
        //        list.concat(taicpu.op_reg_const(A_IN,NR_R29,NIO_SP_HI));
        //        a_adjust_sp(list,-localsize);
        //      end;
        //  end
        //else if not(nostackframe) then
        //  begin
        //    { check if the framepointer is actually used, this is done here because
        //      we have to know the size of the locals (must be 0), avr does not know
        //      an sp based stack }
        //
        //    if not(current_procinfo.procdef.stack_tainting_parameter(calleeside)) and
        //      (localsize=0) then
        //      current_procinfo.framepointer:=NR_NO;
        //
        //    { save int registers,
        //      but only if the procedure returns }
        //    if not(po_noreturn in current_procinfo.procdef.procoptions) then
        //      regs:=rg[R_INTREGISTER].used_in_proc-paramanager.get_volatile_registers_int(pocall_stdcall)
        //    else
        //      regs:=[];
        //    { if the framepointer is potentially used, save it always because we need a proper stack frame,
        //      even if the procedure never returns, the procedure could be e.g. a nested one accessing
        //      an outer stackframe }
        //    if current_procinfo.framepointer<>NR_NO then
        //      regs:=regs+[RS_R28,RS_R29];
        //
        //    for reg:=RS_R31 downto RS_R0 do
        //      if reg in regs then
        //        list.concat(taicpu.op_reg(A_PUSH,newreg(R_INTREGISTER,reg,R_SUBWHOLE)));
        //
        //    if current_procinfo.framepointer<>NR_NO then
        //      begin
        //        list.concat(taicpu.op_reg_const(A_IN,NR_R28,NIO_SP_LO));
        //        list.concat(taicpu.op_reg_const(A_IN,NR_R29,NIO_SP_HI));
        //        a_adjust_sp(list,-localsize);
        //      end;
        //  end;
      end;


    procedure tcgz80.g_proc_exit(list : TAsmList;parasize : longint;nostackframe:boolean);
      var
        regs : tcpuregisterset;
        reg : TSuperRegister;
        LocalSize : longint;
      begin
        { every byte counts for Z80, so if a subroutine is marked as non-returning, we do
          not generate any exit code, so we really trust the noreturn directive
        }
        if po_noreturn in current_procinfo.procdef.procoptions then
          exit;
        list.concat(taicpu.op_none(A_RET));
        //if po_interrupt in current_procinfo.procdef.procoptions then
        //  begin
        //    regs:=rg[R_INTREGISTER].used_in_proc;
        //    if current_procinfo.framepointer<>NR_NO then
        //      begin
        //        regs:=regs+[RS_R28,RS_R29];
        //        LocalSize:=current_procinfo.calc_stackframe_size;
        //        a_adjust_sp(list,LocalSize);
        //      end;
        //
        //    { Reload SREG }
        //    regs:=regs+[RS_R0];
        //
        //    list.concat(taicpu.op_reg(A_POP, NR_R0));
        //    list.concat(taicpu.op_const_reg(A_OUT, $3F, NR_R0));
        //
        //    for reg:=RS_R0 to RS_R31 do
        //      if reg in regs then
        //        list.concat(taicpu.op_reg(A_POP,newreg(R_INTREGISTER,reg,R_SUBWHOLE)));
        //
        //    list.concat(taicpu.op_none(A_RETI));
        //  end
        //else if not(nostackframe) then
        //  begin
        //    regs:=rg[R_INTREGISTER].used_in_proc-paramanager.get_volatile_registers_int(pocall_stdcall);
        //    if current_procinfo.framepointer<>NR_NO then
        //      begin
        //        regs:=regs+[RS_R28,RS_R29];
        //        LocalSize:=current_procinfo.calc_stackframe_size;
        //        a_adjust_sp(list,LocalSize);
        //      end;
        //    for reg:=RS_R0 to RS_R31 do
        //      if reg in regs then
        //        list.concat(taicpu.op_reg(A_POP,newreg(R_INTREGISTER,reg,R_SUBWHOLE)));
        //    list.concat(taicpu.op_none(A_RET));
        //  end
        //else
        //  list.concat(taicpu.op_none(A_RET));
      end;


    procedure tcgz80.a_loadaddr_ref_reg(list : TAsmList;const ref : treference;r : tregister);
      var
        tmpref : treference;
      begin
        list.Concat(tai_comment.Create(strpnew('WARNING! not implemented: a_loadaddr_ref_reg')));
        // if ref.addressmode<>AM_UNCHANGED then
        //   internalerror(2011021701);
        //
        //if assigned(ref.symbol) or (ref.offset<>0) then
        //  begin
        //    reference_reset(tmpref,0,[]);
        //    tmpref.symbol:=ref.symbol;
        //    tmpref.offset:=ref.offset;
        //
        //    if assigned(ref.symbol) and (ref.symbol.typ in [AT_FUNCTION,AT_LABEL]) then
        //      tmpref.refaddr:=addr_lo8_gs
        //    else
        //      tmpref.refaddr:=addr_lo8;
        //    list.concat(taicpu.op_reg_ref(A_LDI,r,tmpref));
        //
        //    if assigned(ref.symbol) and (ref.symbol.typ in [AT_FUNCTION,AT_LABEL]) then
        //      tmpref.refaddr:=addr_hi8_gs
        //    else
        //      tmpref.refaddr:=addr_hi8;
        //    list.concat(taicpu.op_reg_ref(A_LDI,GetNextReg(r),tmpref));
        //
        //    if (ref.base<>NR_NO) then
        //      begin
        //        list.concat(taicpu.op_reg_reg(A_ADD,r,ref.base));
        //        list.concat(taicpu.op_reg_reg(A_ADC,GetNextReg(r),GetNextReg(ref.base)));
        //      end;
        //    if (ref.index<>NR_NO) then
        //      begin
        //        list.concat(taicpu.op_reg_reg(A_ADD,r,ref.index));
        //        list.concat(taicpu.op_reg_reg(A_ADC,GetNextReg(r),GetNextReg(ref.index)));
        //      end;
        //  end
        //else if (ref.base<>NR_NO)then
        //  begin
        //    emit_mov(list,r,ref.base);
        //    emit_mov(list,GetNextReg(r),GetNextReg(ref.base));
        //    if (ref.index<>NR_NO) then
        //      begin
        //        list.concat(taicpu.op_reg_reg(A_ADD,r,ref.index));
        //        list.concat(taicpu.op_reg_reg(A_ADC,GetNextReg(r),GetNextReg(ref.index)));
        //      end;
        //  end
        //else if (ref.index<>NR_NO) then
        //  begin
        //    emit_mov(list,r,ref.index);
        //    emit_mov(list,GetNextReg(r),GetNextReg(ref.index));
        //  end;
      end;


    procedure tcgz80.fixref(list : TAsmList;var ref : treference);
      begin
        internalerror(2011021320);
      end;


    procedure tcgz80.g_concatcopy_move(list : TAsmList;const source,dest : treference;len : tcgint);
      var
        paraloc1,paraloc2,paraloc3 : TCGPara;
        pd : tprocdef;
      begin
        pd:=search_system_proc('MOVE');
        paraloc1.init;
        paraloc2.init;
        paraloc3.init;
        {$warning TODO: implement!!!}
        //paramanager.getintparaloc(list,pd,1,paraloc1);
        //paramanager.getintparaloc(list,pd,2,paraloc2);
        //paramanager.getintparaloc(list,pd,3,paraloc3);
        a_load_const_cgpara(list,OS_SINT,len,paraloc3);
        a_loadaddr_ref_cgpara(list,dest,paraloc2);
        a_loadaddr_ref_cgpara(list,source,paraloc1);
        paramanager.freecgpara(list,paraloc3);
        paramanager.freecgpara(list,paraloc2);
        paramanager.freecgpara(list,paraloc1);
        alloccpuregisters(list,R_INTREGISTER,paramanager.get_volatile_registers_int(pocall_default));
        a_call_name_static(list,'FPC_MOVE');
        dealloccpuregisters(list,R_INTREGISTER,paramanager.get_volatile_registers_int(pocall_default));
        paraloc3.done;
        paraloc2.done;
        paraloc1.done;
      end;


    procedure tcgz80.g_concatcopy(list : TAsmList;const source,dest : treference;len : tcgint);
      var
        countreg,tmpreg : tregister;
        srcref,dstref : treference;
        copysize,countregsize : tcgsize;
        l : TAsmLabel;
        i : longint;
        SrcQuickRef, DestQuickRef : Boolean;
      begin
        list.Concat(tai_comment.Create(strpnew('WARNING! not implemented: g_concatcopy')));
        //if len>16 then
        //  begin
        //    current_asmdata.getjumplabel(l);
        //
        //    reference_reset(srcref,source.alignment,source.volatility);
        //    reference_reset(dstref,dest.alignment,source.volatility);
        //    srcref.base:=NR_R30;
        //    srcref.addressmode:=AM_POSTINCREMENT;
        //    dstref.base:=NR_R26;
        //    dstref.addressmode:=AM_POSTINCREMENT;
        //
        //    copysize:=OS_8;
        //    if len<256 then
        //      countregsize:=OS_8
        //    else if len<65536 then
        //      countregsize:=OS_16
        //    else
        //      internalerror(2011022007);
        //    countreg:=getintregister(list,countregsize);
        //    a_load_const_reg(list,countregsize,len,countreg);
        //    a_loadaddr_ref_reg(list,source,NR_R30);
        //
        //    { only base or index register in dest? }
        //    if ((dest.addressmode=AM_UNCHANGED) and (dest.offset=0) and not(assigned(dest.symbol))) and
        //      ((dest.base<>NR_NO) xor (dest.index<>NR_NO)) then
        //      begin
        //        if dest.base<>NR_NO then
        //          tmpreg:=dest.base
        //        else if dest.index<>NR_NO then
        //          tmpreg:=dest.index
        //        else
        //          internalerror(2016112001);
        //      end
        //    else
        //      begin
        //        tmpreg:=getaddressregister(list);
        //        a_loadaddr_ref_reg(list,dest,tmpreg);
        //      end;
        //
        //    { X is used for spilling code so we can load it
        //      only by a push/pop sequence, this can be
        //      optimized later on by the peephole optimizer
        //    }
        //    list.concat(taicpu.op_reg(A_PUSH,tmpreg));
        //    list.concat(taicpu.op_reg(A_PUSH,GetNextReg(tmpreg)));
        //    list.concat(taicpu.op_reg(A_POP,NR_R27));
        //    list.concat(taicpu.op_reg(A_POP,NR_R26));
        //    cg.a_label(list,l);
        //    list.concat(taicpu.op_reg_ref(GetLoad(srcref),NR_R0,srcref));
        //    list.concat(taicpu.op_ref_reg(GetStore(dstref),dstref,NR_R0));
        //    list.concat(taicpu.op_reg(A_DEC,countreg));
        //    a_jmp_flags(list,F_NE,l);
        //    // keep registers alive
        //    list.concat(taicpu.op_reg_reg(A_MOV,countreg,countreg));
        //  end
        //else
        //  begin
        //    SrcQuickRef:=false;
        //    DestQuickRef:=false;
        //    if not((source.addressmode=AM_UNCHANGED) and
        //           (source.symbol=nil) and
        //           ((source.base=NR_R28) or
        //            (source.base=NR_R30)) and
        //            (source.Index=NR_NO) and
        //            (source.Offset in [0..64-len])) and
        //      not((source.Base=NR_NO) and (source.Index=NR_NO)) then
        //      srcref:=normalize_ref(list,source,NR_R30)
        //    else
        //      begin
        //        SrcQuickRef:=true;
        //        srcref:=source;
        //      end;
        //
        //    if not((dest.addressmode=AM_UNCHANGED) and
        //           (dest.symbol=nil) and
        //           ((dest.base=NR_R28) or
        //            (dest.base=NR_R30)) and
        //            (dest.Index=NR_No) and
        //            (dest.Offset in [0..64-len])) and
        //      not((dest.Base=NR_NO) and (dest.Index=NR_NO)) then
        //      begin
        //        if not(SrcQuickRef) then
        //          begin
        //            { only base or index register in dest? }
        //            if ((dest.addressmode=AM_UNCHANGED) and (dest.offset=0) and not(assigned(dest.symbol))) and
        //              ((dest.base<>NR_NO) xor (dest.index<>NR_NO)) then
        //              begin
        //                if dest.base<>NR_NO then
        //                  tmpreg:=dest.base
        //                else if dest.index<>NR_NO then
        //                  tmpreg:=dest.index
        //                else
        //                  internalerror(2016112002);
        //              end
        //            else
        //              tmpreg:=getaddressregister(list);
        //
        //            dstref:=normalize_ref(list,dest,tmpreg);
        //
        //            { X is used for spilling code so we can load it
        //              only by a push/pop sequence, this can be
        //              optimized later on by the peephole optimizer
        //            }
        //            list.concat(taicpu.op_reg(A_PUSH,tmpreg));
        //            list.concat(taicpu.op_reg(A_PUSH,GetNextReg(tmpreg)));
        //            list.concat(taicpu.op_reg(A_POP,NR_R27));
        //            list.concat(taicpu.op_reg(A_POP,NR_R26));
        //            dstref.base:=NR_R26;
        //          end
        //        else
        //          dstref:=normalize_ref(list,dest,NR_R30);
        //      end
        //    else
        //      begin
        //        DestQuickRef:=true;
        //        dstref:=dest;
        //      end;
        //
        //    for i:=1 to len do
        //      begin
        //        if not(SrcQuickRef) and (i<len) then
        //          srcref.addressmode:=AM_POSTINCREMENT
        //        else
        //          srcref.addressmode:=AM_UNCHANGED;
        //
        //        if not(DestQuickRef) and (i<len) then
        //          dstref.addressmode:=AM_POSTINCREMENT
        //        else
        //          dstref.addressmode:=AM_UNCHANGED;
        //
        //        list.concat(taicpu.op_reg_ref(GetLoad(srcref),NR_R0,srcref));
        //        list.concat(taicpu.op_ref_reg(GetStore(dstref),dstref,NR_R0));
        //
        //        if SrcQuickRef then
        //          inc(srcref.offset);
        //        if DestQuickRef then
        //          inc(dstref.offset);
        //      end;
        //    if not(SrcQuickRef) then
        //      begin
        //        ungetcpuregister(list,srcref.base);
        //        ungetcpuregister(list,GetNextReg(srcref.base));
        //      end;
        //  end;
      end;


    procedure tcgz80.g_overflowCheck(list : TAsmList;const l : tlocation;def : tdef);
      var
        hl : tasmlabel;
        ai : taicpu;
        cond : TAsmCond;
      begin
        list.Concat(tai_comment.Create(strpnew('WARNING! not implemented: g_overflowCheck')));
        //if not(cs_check_overflow in current_settings.localswitches) then
        // exit;
        //current_asmdata.getjumplabel(hl);
        //if not ((def.typ=pointerdef) or
        //       ((def.typ=orddef) and
        //        (torddef(def).ordtype in [u64bit,u16bit,u32bit,u8bit,uchar,
        //                                  pasbool8,pasbool16,pasbool32,pasbool64]))) then
        //  cond:=C_VC
        //else
        //  cond:=C_CC;
        //ai:=Taicpu.Op_Sym(A_BRxx,hl);
        //ai.SetCondition(cond);
        //ai.is_jmp:=true;
        //list.concat(ai);
        //
        //a_call_name(list,'FPC_OVERFLOW',false);
        //a_label(list,hl);
      end;


    procedure tcgz80.g_save_registers(list: TAsmList);
      begin
        { this is done by the entry code }
      end;


    procedure tcgz80.g_restore_registers(list: TAsmList);
      begin
        { this is done by the exit code }
      end;


    procedure tcgz80.a_jmp_cond(list : TAsmList;cond : TOpCmp;l: tasmlabel);
      var
        ai1,ai2 : taicpu;
        hl : TAsmLabel;
      begin
        list.Concat(tai_comment.Create(strpnew('WARNING! not implemented: a_jmp_cond')));
        //ai1:=Taicpu.Op_sym(A_BRxx,l);
        //ai1.is_jmp:=true;
        //hl:=nil;
        //case cond of
        //  OC_EQ:
        //    ai1.SetCondition(C_EQ);
        //  OC_GT:
        //    begin
        //      { emulate GT }
        //      current_asmdata.getjumplabel(hl);
        //      ai2:=Taicpu.Op_Sym(A_BRxx,hl);
        //      ai2.SetCondition(C_EQ);
        //      ai2.is_jmp:=true;
        //      list.concat(ai2);
        //
        //      ai1.SetCondition(C_GE);
        //    end;
        //  OC_LT:
        //    ai1.SetCondition(C_LT);
        //  OC_GTE:
        //    ai1.SetCondition(C_GE);
        //  OC_LTE:
        //    begin
        //      { emulate LTE }
        //      ai2:=Taicpu.Op_Sym(A_BRxx,l);
        //      ai2.SetCondition(C_EQ);
        //      ai2.is_jmp:=true;
        //      list.concat(ai2);
        //
        //      ai1.SetCondition(C_LT);
        //    end;
        //  OC_NE:
        //    ai1.SetCondition(C_NE);
        //  OC_BE:
        //    begin
        //      { emulate BE }
        //      ai2:=Taicpu.Op_Sym(A_BRxx,l);
        //      ai2.SetCondition(C_EQ);
        //      ai2.is_jmp:=true;
        //      list.concat(ai2);
        //
        //      ai1.SetCondition(C_LO);
        //    end;
        //  OC_B:
        //    ai1.SetCondition(C_LO);
        //  OC_AE:
        //    ai1.SetCondition(C_SH);
        //  OC_A:
        //    begin
        //      { emulate A (unsigned GT) }
        //      current_asmdata.getjumplabel(hl);
        //      ai2:=Taicpu.Op_Sym(A_BRxx,hl);
        //      ai2.SetCondition(C_EQ);
        //      ai2.is_jmp:=true;
        //      list.concat(ai2);
        //
        //      ai1.SetCondition(C_SH);
        //    end;
        //  else
        //    internalerror(2011082501);
        //end;
        //list.concat(ai1);
        //if assigned(hl) then
        //  a_label(list,hl);
      end;


    procedure tcgz80.emit_mov(list: TAsmList;reg2: tregister; reg1: tregister);
      var
         instr: taicpu;
      begin
       instr:=taicpu.op_reg_reg(A_LD,reg2,reg1);
       list.Concat(instr);
       { Notify the register allocator that we have written a move instruction so
         it can try to eliminate it. }
       add_move_instruction(instr);
      end;


    procedure tcg64fz80.a_op64_reg_reg(list : TAsmList;op:TOpCG;size : tcgsize;regsrc,regdst : tregister64);
      begin
         if not(size in [OS_S64,OS_64]) then
           internalerror(2012102402);
         tcgz80(cg).a_op_reg_reg_internal(list,Op,size,regsrc.reglo,regsrc.reghi,regdst.reglo,regdst.reghi);
      end;


    procedure tcg64fz80.a_op64_const_reg(list : TAsmList;op:TOpCG;size : tcgsize;value : int64;reg : tregister64);
      begin
        tcgz80(cg).a_op_const_reg_internal(list,Op,size,value,reg.reglo,reg.reghi);
      end;


    function GetByteLoc(const loc : tlocation; nr : byte) : tlocation;
      var
        i : Integer;
      begin
        Result:=loc;
        Result.size:=OS_8;
        case loc.loc of
          LOC_REFERENCE,LOC_CREFERENCE:
            inc(Result.reference.offset,nr);
          LOC_REGISTER,LOC_CREGISTER:
            begin
              if nr>=4 then
                Result.register:=Result.register64.reghi;
              nr:=nr mod 4;
              for i:=1 to nr do
                Result.register:=GetNextReg(Result.register);
            end;
          LOC_CONSTANT:
            if loc.size in [OS_64,OS_S64] then
              Result.value:=(Result.value64 shr (nr*8)) and $ff
            else
              Result.value:=(Result.value shr (nr*8)) and $ff;
          else
            Internalerror(2019020902);
        end;
      end;


    procedure create_codegen;
      begin
        cg:=tcgz80.create;
        cg64:=tcg64fz80.create;
      end;

end.