fpc/compiler/cga68k.pas

{
    $Id$
    Copyright (c) 1993-98 by Florian Klaempfl, Carl Eric Codere

    This unit generates 68000 (or better) assembler from the parse tree

    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 cga68k;

  interface

    uses
       objects,cobjects,verbose,systems,globals,tree,symtable,types,strings,
       pass_1,hcodegen,aasm,m68k,tgen68k,files,gdb;

    procedure emitl(op : tasmop;var l : plabel);
    procedure emit_reg_reg(i : tasmop;s : topsize;reg1,reg2 : tregister);
    procedure emitcall(const routine:string;add_to_externals : boolean);
    procedure emitloadord2reg(location:Tlocation;orddef:Porddef;
                              destreg:Tregister;delloc:boolean);
    { produces jumps to true respectively false labels using boolean expressions }
    procedure maketojumpbool(p : ptree);
    procedure emitoverflowcheck;
    procedure push_int(l : longint);
    function maybe_push(needed : byte;p : ptree) : boolean;
    procedure restore(p : ptree);
    procedure emit_push_mem(const ref : treference);
    procedure emitpushreferenceaddr(const ref : treference);
    procedure swaptree(p: ptree);
    procedure copystring(const dref,sref : treference;len : byte);
    procedure concatcopy(source,dest : treference;size : longint;delsource : boolean);
    { see implementation }
    procedure maybe_loada5;
    procedure emit_bounds_check(hp: treference; index: tregister);
    procedure loadstring(p:ptree);

    procedure floatload(t : tfloattype;const ref : treference; var location:tlocation);
    { return a float op_size from a floatb type  }
    { also does some error checking for problems }
    function getfloatsize(t: tfloattype): topsize;
    procedure floatstore(t : tfloattype;var location:tlocation; const ref:treference);
{    procedure floatloadops(t : tfloattype;var op : tasmop;var s : topsize);
    procedure floatstoreops(t : tfloattype;var op : tasmop;var s : topsize); }

    procedure firstcomplex(p : ptree);
    procedure secondfuncret(var p : ptree);

    { initialize respectively terminates the code generator }
    { for a new module or procedure                         }
    procedure codegen_doneprocedure;
    procedure codegen_donemodule;
    procedure codegen_newmodule;
    procedure codegen_newprocedure;

    { generate entry code for a procedure.}
    procedure genentrycode(const proc_names:Tstringcontainer;make_global:boolean;
                           stackframe:longint;
                           var parasize:longint;var nostackframe:boolean);
    { generate the exit code for a procedure. }
    procedure genexitcode(parasize:longint;nostackframe:boolean);


  implementation

    {
    procedure genconstadd(size : topsize;l : longint;const str : string);

      begin
         if l=0 then
         else if l=1 then
           exprasmlist^.concat(new(pai68k,op_A_INC,size,str)
         else if l=-1 then
           exprasmlist^.concat(new(pai68k,op_A_INC,size,str)
         else
           exprasmlist^.concat(new(pai68k,op_ADD,size,'$'+tostr(l)+','+str);
      end;
    }
    procedure copystring(const dref,sref : treference;len : byte);

      var
         pushed : tpushed;

      begin
         pushusedregisters(pushed,$ffff);
         emitpushreferenceaddr(dref);
         emitpushreferenceaddr(sref);
         push_int(len);
         emitcall('STRCOPY',true);
         maybe_loada5;
         popusedregisters(pushed);
      end;


    procedure loadstring(p:ptree);
      begin
        case p^.right^.resulttype^.deftype of
         stringdef : begin
                       { load a string ... }
                       { here two possible choices:      }
                       { if it is a char, then simply    }
                       { load 0 length string            }
                       if (p^.right^.treetype=stringconstn) and
                          (p^.right^.values^='') then
                        exprasmlist^.concat(new(pai68k,op_const_ref(
                           A_MOVE,S_B,0,newreference(p^.left^.location.reference))))
                       else
                        copystring(p^.left^.location.reference,p^.right^.location.reference,
                           min(pstringdef(p^.right^.resulttype)^.len,pstringdef(p^.left^.resulttype)^.len));
                     end;
            orddef : begin
                       if p^.right^.treetype=ordconstn then
                        begin
                            exprasmlist^.concat(new(pai68k,op_const_ref(A_MOVE,S_W,p^.right^.value*256+1,
                              newreference(p^.left^.location.reference))))
                        end
                       else
                         begin
                            { not so elegant (goes better with extra register }
                            if (p^.right^.location.loc in [LOC_REGISTER,LOC_CREGISTER]) then
                              begin
                                 exprasmlist^.concat(new(pai68k,op_reg_reg(
                                    A_MOVE,S_L,p^.right^.location.register,R_D0)));
                                 ungetregister32(p^.right^.location.register);
                              end
                            else
                              begin
                                 exprasmlist^.concat(new(pai68k,op_ref_reg(
                                    A_MOVE,S_L,newreference(p^.right^.location.reference),R_D0)));
                                 del_reference(p^.right^.location.reference);
                              end;
                            if (opt_processors = MC68020) then
                             { alignment is not a problem on the 68020 and higher processors }
                              Begin
                               { add length of string to word }
                                exprasmlist^.concat(new(pai68k,op_const_reg(A_OR,S_W,$0100,R_D0)));
                               { put back into mem ...        }
                                exprasmlist^.concat(new(pai68k,op_reg_ref(A_MOVE,S_W,R_D0,
                                  newreference(p^.left^.location.reference))));
                             end
                           else
                             Begin
                              { alignment can cause problems }
                              { add length of string to ref }
                               exprasmlist^.concat(new(pai68k,op_const_ref(A_MOVE,S_B,1,
                                  newreference(p^.left^.location.reference))));
                               if abs(p^.left^.location.reference.offset) >= 1 then
                                 Begin
                                 { temporarily decrease offset }
                                   Inc(p^.left^.location.reference.offset);
                                   exprasmlist^.concat(new(pai68k,op_reg_ref(A_MOVE,S_B,R_D0,
                                     newreference(p^.left^.location.reference))));
                                   Dec(p^.left^.location.reference.offset);
                                 { restore offset }
                                 end
                               else
                                Begin
                                 Comment(V_Debug,'SecondChar2String() internal error.');
                                 internalerror(34);
                                end;
                             end;
                         end;
                       end;
        else
         Message(sym_e_type_mismatch);
        end;
      end;





    procedure restore(p : ptree);

      var
         hregister :  tregister;

      begin
         hregister:=getregister32;
         exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_L,R_SPPULL,hregister)));
         if (p^.location.loc=LOC_REGISTER) or (p^.location.loc=LOC_CREGISTER) then
           begin
              p^.location.register:=hregister;
           end
         else
           begin
              reset_reference(p^.location.reference);
              p^.location.reference.index:=hregister;
              set_location(p^.left^.location,p^.location);
           end;
      end;

    function maybe_push(needed : byte;p : ptree) : boolean;

      var
         pushed : boolean;
         {hregister : tregister; }
         reg: tregister;
      begin
         if needed>usablereg32 then
           begin
              if (p^.location.loc=LOC_REGISTER) or
                 (p^.location.loc=LOC_CREGISTER) then
                begin
                   pushed:=true;
                   exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_L,p^.location.register,R_SPPUSH)));
                   ungetregister32(p^.location.register);
                end
              else if ((p^.location.loc=LOC_MEM) or
                       (p^.location.loc=LOC_REFERENCE)
                      ) and
                      ((p^.location.reference.base<>R_NO) or
                       (p^.location.reference.index<>R_NO)
                      ) then
                  begin
                     del_reference(p^.location.reference);
                     exprasmlist^.concat(new(pai68k,op_ref_reg(A_LEA,S_L,newreference(p^.location.reference),
               R_A0)));
             exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_L,R_A0,R_SPPUSH)));
                     pushed:=true;
                  end
              else pushed:=false;
           end
         else pushed:=false;
         maybe_push:=pushed;
      end;


    { emit out of range check for arrays and sets}
    procedure emit_bounds_check(hp: treference; index: tregister);
    { index = index of array to check }
    { memory of range check information for array }
     var
      hl : plabel;
     begin
        if (opt_processors = MC68020) then
          begin
             exprasmlist^.concat(new(pai68k, op_ref_reg(A_CMP2,S_L,newreference(hp),index)));
             getlabel(hl);
             emitl(A_BCC, hl);
             exprasmlist^.concat(new(pai68k, op_const_reg(A_MOVE,S_L,201,R_D0)));
             emitcall('HALT_ERROR',true);
             emitl(A_LABEL, hl);
          end
        else
          begin
            exprasmlist^.concat(new(pai68k, op_ref_reg(A_LEA,S_L,newreference(hp), R_A1)));
            exprasmlist^.concat(new(pai68k, op_reg_reg(A_MOVE, S_L, index, R_D0)));
            emitcall('RE_BOUNDS_CHECK',true);
          end;
     end;



    function getfloatsize(t: tfloattype): topsize;
    begin
      case t of
      s32real: getfloatsize := S_S;
      s64real: getfloatsize := S_Q;
      s80real: getfloatsize := S_X;
{$ifdef extdebug}
    else {else case }
      begin
        Comment(V_Debug,' getfloatsize() trying to get unknown size.');
        internalerror(12);
      end;
{$endif}
     end;
    end;

    procedure emitl(op : tasmop;var l : plabel);

      begin
         if op=A_LABEL then
           exprasmlist^.concat(new(pai_label,init(l)))
         else
           exprasmlist^.concat(new(pai_labeled,init(op,l)))
      end;

    procedure emit_reg_reg(i : tasmop;s : topsize;reg1,reg2 : tregister);

      begin
         if (reg1 <> reg2) or (i <> A_MOVE) then
           exprasmlist^.concat(new(pai68k,op_reg_reg(i,s,reg1,reg2)));
      end;


    procedure emitcall(const routine:string;add_to_externals : boolean);

     begin
        exprasmlist^.concat(new(pai68k,op_csymbol(A_JSR,S_NO,newcsymbol(routine,0))));
        if assem_need_external_list and add_to_externals and
           not (cs_compilesystem in aktswitches) then
          concat_external(routine,EXT_NEAR);
     end;


    procedure maketojumpbool(p : ptree);

      begin
         if p^.error then
           exit;
         if (p^.resulttype^.deftype=orddef) and
            (porddef(p^.resulttype)^.typ=bool8bit) then
           begin
              if is_constboolnode(p) then
                begin
                   if p^.value<>0 then
                     emitl(A_JMP,truelabel)
                   else emitl(A_JMP,falselabel);
                end
              else
                begin
                   case p^.location.loc of
                      LOC_CREGISTER,LOC_REGISTER : begin
                                        exprasmlist^.concat(new(pai68k,op_reg(A_TST,S_B,p^.location.register)));
                                        ungetregister32(p^.location.register);
                                        emitl(A_BNE,truelabel);
                                        emitl(A_JMP,falselabel);
                                     end;
                      LOC_MEM,LOC_REFERENCE : begin
                                        exprasmlist^.concat(new(pai68k,op_ref(
                                          A_TST,S_B,newreference(p^.location.reference))));
                                        del_reference(p^.location.reference);
                                        emitl(A_BNE,truelabel);
                                        emitl(A_JMP,falselabel);
                                     end;
                      LOC_FLAGS : begin
                                     emitl(flag_2_jmp[p^.location.resflags],truelabel);
                                     emitl(A_JMP,falselabel);
                                  end;
                   end;
                end;
           end
         else
          Message(sym_e_type_mismatch);
      end;

    procedure emitoverflowcheck;

      var
         hl : plabel;

      begin
         if cs_check_overflow in aktswitches  then
           begin
              getlabel(hl);
              emitl(A_BVC,hl);
              emitcall('RE_OVERFLOW',true);
              emitl(A_LABEL,hl);
           end;
      end;

    procedure push_int(l : longint);

      begin
         if (l = 0) and (opt_processors = MC68020) then
           begin
          exprasmlist^.concat(new(pai68k,op_reg(A_CLR,S_L,R_D6)));
              exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_L,
          R_D6, R_SPPUSH)));
           end
         else
         if not(cs_littlesize in aktswitches) and (l >= -128) and (l <= 127) then
           begin
           exprasmlist^.concat(new(pai68k,op_const_reg(A_MOVEQ,S_L,l,R_D6)));
           exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_L,R_D6,R_SPPUSH)));
           end
         else
           exprasmlist^.concat(new(pai68k,op_const_reg(A_MOVE,S_L,l,R_SPPUSH)));
      end;

    procedure emit_push_mem(const ref : treference);

      begin
         if ref.isintvalue then
           push_int(ref.offset)
         else
           exprasmlist^.concat(new(pai68k,op_ref(A_PEA,S_L,newreference(ref))));
      end;


    { USES REGISTER R_A1 }
    procedure emitpushreferenceaddr(const ref : treference);

      begin
         if ref.isintvalue then
           push_int(ref.offset)
         else
           begin
              if (ref.base=R_NO) and (ref.index=R_NO) then
                exprasmlist^.concat(new(pai68k,op_ref(A_PEA,S_L,
                    newreference(ref))))
              else if (ref.base=R_NO) and (ref.index<>R_NO) and
                 (ref.offset=0) and (ref.scalefactor=0) and (ref.symbol=nil) then
                exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_L,
                    ref.index,R_SPPUSH)))
              else if (ref.base<>R_NO) and (ref.index=R_NO) and
                 (ref.offset=0) and (ref.symbol=nil) then
                exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_L,ref.base,R_SPPUSH)))
              else
                begin
                   exprasmlist^.concat(new(pai68k,op_ref_reg(A_LEA,S_L,newreference(ref),R_A1)));
                   exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_L,R_A1,R_SPPUSH)));
                end;
           end;
        end;

    procedure swaptree(p:Ptree);

    var swapp:Ptree;

    begin
        swapp:=p^.right;
        p^.right:=p^.left;
        p^.left:=swapp;
        p^.swaped:=not(p^.swaped);
    end;


procedure genentrycode(const proc_names:Tstringcontainer;make_global:boolean;
                       stackframe:longint;
                       var parasize:longint;var nostackframe:boolean);

{Generates the entry code for a procedure.}

var hs:string;
    hp:Pused_unit;
    unitinits:taasmoutput;
{$ifdef GDB}
    oldaktprocname : string;
    stab_function_name:Pai_stab_function_name;
{$endif GDB}
begin
    if (aktprocsym^.definition^.options and poproginit<>0) then
        begin
            {Init the stack checking.}
            if (cs_check_stack in aktswitches) and
             (target_info.target=target_linux) then
                begin
                    procinfo.aktentrycode^.insert(new(pai68k,
                     op_csymbol(A_JSR,S_NO,newcsymbol('INIT_STACK_CHECK',0))));
                end;

            unitinits.init;

            {Call the unit init procedures.}
            hp:=pused_unit(usedunits.first);
            while assigned(hp) do
                begin
                    { call the unit init code and make it external }
                    if (hp^.u^.flags and uf_init)<>0 then
                        begin
                           unitinits.concat(new(pai68k,op_csymbol(A_JSR,S_NO,newcsymbol('INIT$$'+hp^.u^.unitname^,0))));
                           externals^.concat(new(pai_external,init('INIT$$'+hp^.u^.unitname^,EXT_NEAR)));
                        end;
                   hp:=pused_unit(hp^.next);
                end;
              procinfo.aktentrycode^.insertlist(@unitinits);
              unitinits.done;
        end;

        { a constructor needs a help procedure }
        if (aktprocsym^.definition^.options and poconstructor)<>0 then
        begin
           if procinfo._class^.isclass then
             begin
              procinfo.aktentrycode^.insert(new(pai_labeled,init(A_BEQ,quickexitlabel)));
              procinfo.aktentrycode^.insert(new(pai68k,op_csymbol(A_JSR,S_NO,
              newcsymbol('NEW_CLASS',0))));
              concat_external('NEW_CLASS',EXT_NEAR);
             end
           else
             begin
              procinfo.aktentrycode^.insert(new(pai_labeled,init(A_BEQ,quickexitlabel)));
              procinfo.aktentrycode^.insert(new(pai68k,op_csymbol(A_JSR,S_NO,
              newcsymbol('HELP_CONSTRUCTOR',0))));
              concat_external('HELP_CONSTRUCTOR',EXT_NEAR);
             end;
        end;
    { don't load ESI, does the caller }

    { omit stack frame ? }
    if procinfo.framepointer=stack_pointer then
        begin
            Message(cg_d_stackframe_omited);
            nostackframe:=true;
            if (aktprocsym^.definition^.options and (pounitinit or poproginit)<>0) then
                parasize:=0
            else
                parasize:=aktprocsym^.definition^.parast^.datasize+procinfo.call_offset;
        end
    else
        begin
             if (aktprocsym^.definition^.options and (pounitinit or poproginit)<>0) then
                parasize:=0
             else
                parasize:=aktprocsym^.definition^.parast^.datasize+procinfo.call_offset-8;
            nostackframe:=false;
            if stackframe<>0 then
                begin
                    if cs_littlesize in aktswitches  then
                        begin
                            if (cs_check_stack in aktswitches) and
                             (target_info.target<>target_linux) then
                                begin
                                    procinfo.aktentrycode^.insert(new(pai68k,
                                     op_csymbol(A_JSR,S_NO,newcsymbol('STACKCHECK',0))));
                                    procinfo.aktentrycode^.insert(new(pai68k,op_const_reg(A_MOVE,S_L,stackframe,R_SPPUSH)));
                                end;
                            { to allocate stack space }
                            { here we allocate space using link signed 16-bit version }
                            { -ve offset to allocate stack space! }
                            if (stackframe > -32767) and (stackframe < 32769) then
                              procinfo.aktentrycode^.insert(new(pai68k,op_reg_const(A_LINK,S_W,R_A6,-stackframe)))
                            else
                              Message(cg_e_stacklimit_in_local_routine);
                        end
                    else
                        begin
                          { Not to complicate the code generator too much, and since some  }
                          { of the systems only support this format, the stackframe cannot }
                          { exceed 32K in size.                                            }
                          if (stackframe > -32767) and (stackframe < 32769) then
                            begin
                              procinfo.aktentrycode^.insert(new(pai68k,op_const_reg(A_SUB,S_L,stackframe,R_SP)));
                              if (cs_check_stack in aktswitches) then
                                begin
                                  procinfo.aktentrycode^.insert(new(pai68k,
                                   op_csymbol(A_JSR,S_NO,newcsymbol('STACKCHECK',0))));
                                  procinfo.aktentrycode^.insert(new(pai68k,op_const_reg(A_MOVE,S_L,
                                    stackframe,R_SPPUSH)));
                                  concat_external('STACKCHECK',EXT_NEAR);
                                end;
                               procinfo.aktentrycode^.insert(new(pai68k,op_reg_reg(A_MOVE,S_L,R_SP,R_A6)));
                               procinfo.aktentrycode^.insert(new(pai68k,op_reg_reg(A_MOVE,S_L,R_A6,R_SPPUSH)));
                            end
                          else
                            Message(cg_e_stacklimit_in_local_routine);
                        end;
                end {endif stackframe<>0 }
            else
               begin
                 procinfo.aktentrycode^.insert(new(pai68k,op_reg_reg(A_MOVE,S_L,R_SP,R_A6)));
                 procinfo.aktentrycode^.insert(new(pai68k,op_reg_reg(A_MOVE,S_L,R_A6,R_SPPUSH)));
               end;
        end;

    if (aktprocsym^.definition^.options and pointerrupt)<>0 then
        generate_interrupt_stackframe_entry;

    {proc_names.insert(aktprocsym^.definition^.mangledname);}

    if (aktprocsym^.definition^.owner^.symtabletype=globalsymtable) or
     ((procinfo._class<>nil) and (procinfo._class^.owner^.
     symtabletype=globalsymtable)) then
        make_global:=true;
    hs:=proc_names.get;

{$IfDef GDB}
    if (cs_debuginfo in aktswitches) and
     target_info.use_function_relative_addresses then
        stab_function_name := new(pai_stab_function_name,init(strpnew(hs)));
      oldaktprocname:=aktprocsym^.name;
{$EndIf GDB}


    while hs<>'' do
        begin
              if make_global then
                procinfo.aktentrycode^.insert(new(pai_symbol,init_global(hs)))
              else
                procinfo.aktentrycode^.insert(new(pai_symbol,init(hs)));
{$ifdef GDB}
            if (cs_debuginfo in aktswitches) and
             target_info.use_function_relative_addresses then
            begin
            procinfo.aktentrycode^.insert(new(pai_stab_function_name,init(strpnew(hs))));
              { This is not a nice solution to save the name, change it and restore when done }
                 aktprocsym^.setname(hs);
                 procinfo.aktentrycode^.insert(new(pai_stabs,init(aktprocsym^.stabstring)));
        end;
{$endif GDB}
              hs:=proc_names.get;
        end;
{$ifdef GDB}
      aktprocsym^.setname(oldaktprocname);

    if (cs_debuginfo in aktswitches) then
        begin
            if target_info.use_function_relative_addresses then
                procinfo.aktentrycode^.insert(stab_function_name);
            if make_global or ((procinfo.flags and pi_is_global) <> 0) then
                aktprocsym^.is_global := True;
            {This is dead code! Because lexlevel is increased at the
             start of compile_proc_body it can never be zero.}
{           if (lexlevel > 0) and (oldprocsym^.definition^.localst^.name = nil) then
                if oldprocsym^.owner^.symtabletype = objectsymtable then
                    oldprocsym^.definition^.localst^.name := stringdup(oldprocsym^.owner^.name^+'_'+oldprocsym^.name)
                else
                    oldprocsym^.definition^.localst^.name := stringdup(oldprocsym^.name);}
            aktprocsym^.isstabwritten:=true;
        end;
{$endif GDB}
    { Alignment required for Motorola }
    procinfo.aktentrycode^.insert(new(pai_align,init(2)));
{$ifdef extdebug}
    procinfo.aktentrycode^.insert(new(pai_direct,init(strpnew(target_info.newline))));
{$endif extdebug}
end;

{Generate the exit code for a procedure.}
procedure genexitcode(parasize:longint;nostackframe:boolean);

var hr:Preference;          {This is for function results.}
    op:Tasmop;
    s:Topsize;

begin
    { !!!! insert there automatic destructors }

    procinfo.aktexitcode^.insert(new(pai_label,init(aktexitlabel)));

    { call the destructor help procedure }
    if (aktprocsym^.definition^.options and podestructor)<>0 then
     begin
       if procinfo._class^.isclass then
         begin
           procinfo.aktexitcode^.insert(new(pai68k,op_csymbol(A_JSR,S_NO,
             newcsymbol('DISPOSE_CLASS',0))));
           concat_external('DISPOSE_CLASS',EXT_NEAR);
         end
       else
         begin
           procinfo.aktexitcode^.insert(new(pai68k,op_csymbol(A_JSR,S_NO,
             newcsymbol('HELP_DESTRUCTOR',0))));
           concat_external('HELP_DESTRUCTOR',EXT_NEAR);
         end;
     end;

    { call __EXIT for main program }
    { ????????? }
    if (aktprocsym^.definition^.options and poproginit)<>0 then
     begin
       procinfo.aktexitcode^.concat(new(pai68k,op_csymbol(A_JSR,S_NO,newcsymbol('__EXIT',0))));
       externals^.concat(new(pai_external,init('__EXIT',EXT_NEAR)));
     end;

    { handle return value }
    if (aktprocsym^.definition^.options and poassembler)=0 then
        if (aktprocsym^.definition^.options and poconstructor)=0 then
            begin
                if procinfo.retdef<>pdef(voiddef) then
                    begin
                        if not procinfo.funcret_is_valid then
                          Message(sym_w_function_result_not_set);
                        new(hr);
                        reset_reference(hr^);
                        hr^.offset:=procinfo.retoffset;
                        hr^.base:=procinfo.framepointer;
                        if (procinfo.retdef^.deftype=orddef) then
                            begin
                                case porddef(procinfo.retdef)^.typ of
                                    s32bit,u32bit :
                                        procinfo.aktexitcode^.concat(new(pai68k,op_ref_reg(A_MOVE,S_L,hr,R_D0)));
                                    u8bit,s8bit,uchar,bool8bit :
                                        procinfo.aktexitcode^.concat(new(pai68k,op_ref_reg(A_MOVE,S_B,hr,R_D0)));
                                    s16bit,u16bit :
                                        procinfo.aktexitcode^.concat(new(pai68k,op_ref_reg(A_MOVE,S_W,hr,R_D0)));
                                end;
                            end
                        else
                            if (procinfo.retdef^.deftype in [pointerdef,enumdef,procvardef]) or
                             ((procinfo.retdef^.deftype=setdef) and
                             (psetdef(procinfo.retdef)^.settype=smallset)) then
                                procinfo.aktexitcode^.concat(new(pai68k,op_ref_reg(A_MOVE,S_L,hr,R_D0)))
                            else
                                if (procinfo.retdef^.deftype=floatdef) then
                                    begin
                                        if pfloatdef(procinfo.retdef)^.typ=f32bit then
                                            begin
                                                { Isnt this missing ? }
                                                procinfo.aktexitcode^.concat(new(pai68k,op_ref_reg(A_MOVE,S_L,hr,R_D0)));
                                            end
                                        else
                                            begin
                                             { how the return value is handled                          }
                                             { if in FPU mode, return in FP0                            }
                                             if (pfloatdef(procinfo.retdef)^.typ = s32real)
                                              and (cs_fp_emulation in aktswitches) then
                                              begin
                                                procinfo.aktexitcode^.concat(new(pai68k,op_ref_reg(A_MOVE,
                                                  S_L,hr,R_D0)))
                                              end
                                             else
                                              begin
                                               if cs_fp_emulation in aktswitches then
                                                 procinfo.aktexitcode^.concat(new(pai68k,op_ref_reg(A_MOVE,
                                                    S_L,hr,R_D0)))
                                               else
                                                 procinfo.aktexitcode^.concat(new(pai68k,op_ref_reg(A_FMOVE,
                                                 getfloatsize(pfloatdef(procinfo.retdef)^.typ),hr,R_FP0)));
                                             end;
                                           end;
                                    end
                                else
                                    dispose(hr);
                    end
            end
        else
            begin
                { successful constructor deletes the zero flag }
                { and returns self in accumulator              }
                procinfo.aktexitcode^.concat(new(pai_label,init(quickexitlabel)));
                { eax must be set to zero if the allocation failed !!! }
                procinfo.aktexitcode^.concat(new(pai68k,op_reg_reg(A_MOVE,S_L,R_A5,R_D0)));
                { faster then OR on mc68000/mc68020 }
                procinfo.aktexitcode^.concat(new(pai68k,op_reg(A_TST,S_L,R_D0)));
            end;
    procinfo.aktexitcode^.concat(new(pai_label,init(aktexit2label)));
    if not(nostackframe) then
        procinfo.aktexitcode^.concat(new(pai68k,op_reg(A_UNLK,S_NO,R_A6)));

    { at last, the return is generated }

    if (aktprocsym^.definition^.options and pointerrupt)<>0 then
        generate_interrupt_stackframe_exit
    else
        if (parasize=0) or ((aktprocsym^.definition^.options and poclearstack)<>0)
        then
            {Routines with the poclearstack flag set use only a ret.}
            { also routines with parasize=0           }
            procinfo.aktexitcode^.concat(new(pai68k,op_none(A_RTS,S_NO)))
        else
            { return with immediate size possible here }
            { signed!                                  }
            if (opt_processors = MC68020) and (parasize < $7FFF) then
                procinfo.aktexitcode^.concat(new(pai68k,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)         }
                    procinfo.aktexitcode^.concat(new(pai68k,op_reg_reg(
                         A_MOVE,S_L,R_SPPULL,R_A0)));
                    { can we do a quick addition ... }
                    if (parasize > 0) and (parasize < 9) then
                       procinfo.aktexitcode^.concat(new(pai68k,op_const_reg(
                         A_ADD,S_L,parasize,R_SP)))
                    else { nope ... }
                       procinfo.aktexitcode^.concat(new(pai68k,op_const_reg(
                         A_ADD,S_L,parasize,R_SP)));
                    { endif }
                    { restore the PC counter (push it on the stack)       }
                    procinfo.aktexitcode^.concat(new(pai68k,op_reg_reg(
                         A_MOVE,S_L,R_A0,R_SPPUSH)));
                    procinfo.aktexitcode^.concat(new(pai68k,op_none(
                      A_RTS,S_NO)))
               end;
{$ifdef GDB}
    if cs_debuginfo in aktswitches  then
        begin
            aktprocsym^.concatstabto(procinfo.aktexitcode);
            if assigned(procinfo._class) then
                procinfo.aktexitcode^.concat(new(pai_stabs,init(strpnew(
                 '"$t:v'+procinfo._class^.numberstring+'",'+
                 tostr(N_PSYM)+',0,0,'+tostr(procinfo.esi_offset)))));

            if (porddef(aktprocsym^.definition^.retdef) <> voiddef) then
                procinfo.aktexitcode^.concat(new(pai_stabs,init(strpnew(
                 '"'+aktprocsym^.name+':X'+aktprocsym^.definition^.retdef^.numberstring+'",'+
                 tostr(N_PSYM)+',0,0,'+tostr(procinfo.retoffset)))));

            procinfo.aktexitcode^.concat(new(pai_stabn,init(strpnew('192,0,0,'
             +aktprocsym^.definition^.mangledname))));

            procinfo.aktexitcode^.concat(new(pai_stabn,init(strpnew('224,0,0,'
             +lab2str(aktexit2label)))));
        end;
{$endif * GDB *}
end;


    { USES REGISTERS R_A0 AND R_A1 }
    procedure concatcopy(source,dest : treference;size : longint;delsource : boolean);

      var
         ecxpushed : boolean;
         helpsize : longint;
         i : byte;
         reg8,reg32 : tregister;
         swap : boolean;
         hregister : tregister;
         iregister : tregister;
         jregister : tregister;
         hp1 : treference;
         hp2 : treference;
         hl : plabel;
      begin
         hregister := getregister32;
         if delsource then
           del_reference(source);

         { from 12 bytes movs is being used }
         if (size<=8) or (not(cs_littlesize in aktswitches) and (size<=12)) then
           begin
              helpsize:=size div 4;
              { move a dword x times }
              for i:=1 to helpsize do
                begin
                   exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_L,newreference(source),hregister)));
                   exprasmlist^.concat(new(pai68k,op_reg_ref(A_MOVE,S_L,hregister,newreference(dest))));
                   inc(source.offset,4);
                   inc(dest.offset,4);
                   dec(size,4);
                end;
              { move a word }
              if size>1 then
                begin
                   exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_W,newreference(source),hregister)));
                   exprasmlist^.concat(new(pai68k,op_reg_ref(A_MOVE,S_W,hregister,newreference(dest))));
                   inc(source.offset,2);
                   inc(dest.offset,2);
                   dec(size,2);
                end;
              { move a single byte }
              if size>0 then
                begin
                  exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_B,newreference(source),hregister)));
                  exprasmlist^.concat(new(pai68k,op_reg_ref(A_MOVE,S_B,hregister,newreference(dest))));
                end

           end
           else
           begin
              if (usableaddress > 1) then
                begin
                    iregister := getaddressreg;
                    jregister := getaddressreg;
                end
              else
              if (usableaddress = 1) then
                begin
                    iregister := getaddressreg;
                    jregister := R_A1;
                end
              else
                begin
                    iregister := R_A0;
                    jregister := R_A1;
                end;
              { reference for move (An)+,(An)+ }
              reset_reference(hp1);
              hp1.base := iregister;   { source register }
              hp1.direction := dir_inc;
              reset_reference(hp2);
              hp2.base := jregister;
              hp1.direction := dir_inc;
              { iregister = source }
              { jregister = destination }
              exprasmlist^.concat(new(pai68k,op_ref_reg(A_LEA,S_L,newreference(source),iregister)));
              exprasmlist^.concat(new(pai68k,op_ref_reg(A_LEA,S_L,newreference(dest),jregister)));

              { double word move }
              helpsize := size - size mod 4;
              size := size mod 4;
              exprasmlist^.concat(new(pai68k,op_const_reg(A_MOVE,S_L,helpsize div 4,hregister)));
              getlabel(hl);
              emitl(A_LABEL,hl);
              exprasmlist^.concat(new(pai68k,op_ref_ref(A_MOVE,S_L,newreference(hp1),newreference(hp2))));
              exprasmlist^.concat(new(pai68k,op_const_reg(A_SUBQ,S_L,4,hregister)));
              emitl(A_BNE,hl);
              if size > 1 then
                begin
                    dec(size,2);
                    exprasmlist^.concat(new(pai68k,op_ref_ref(A_MOVE,S_W,newreference(hp1), newreference(hp2))));
                end;
              if size = 1 then
                    exprasmlist^.concat(new(pai68k,op_ref_ref(A_MOVE,S_B,newreference(hp1), newreference(hp2))));
       { restore the registers that we have just used olny if they are used! }
          if jregister = R_A1 then
            hp2.base := R_NO;
          if iregister = R_A0 then
            hp1.base := R_NO;
          del_reference(hp1);
          del_reference(hp2);
           end;

           { loading SELF-reference again }
           maybe_loada5;

           if delsource then
               ungetiftemp(source);

           ungetregister32(hregister);
    end;


    procedure emitloadord2reg(location:Tlocation;orddef:Porddef;
                              destreg:Tregister;delloc:boolean);

    {A lot smaller and less bug sensitive than the original unfolded loads.}

    var tai:pai68k;
        r:Preference;

    begin
        case location.loc of
            LOC_REGISTER,LOC_CREGISTER:
                begin
                    case orddef^.typ of
                        u8bit: begin
                                 exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_L,location.register,destreg)));
                                 exprasmlist^.concat(new(pai68k,op_const_reg(A_ANDI,S_L,$FF,destreg)));
                               end;
                        s8bit: begin
                                 exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_B,location.register,destreg)));
                                 if (opt_processors <> MC68020) then
                                  begin
                                 { byte to word }
                                     exprasmlist^.concat(new(pai68k,op_reg(A_EXT,S_W,destreg)));
                                 { word to long }
                                     exprasmlist^.concat(new(pai68k,op_reg(A_EXT,S_L,destreg)));
                                  end
                                 else { 68020+ and later only }
                                     exprasmlist^.concat(new(pai68k,op_reg(A_EXTB,S_L,destreg)));
                                end;
                        u16bit: begin
                                 exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_W,location.register,destreg)));
                                 exprasmlist^.concat(new(pai68k,op_const_reg(A_ANDI,S_L,$FFFF,destreg)));
                                end;
                        s16bit: begin
                                 exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_W,location.register,destreg)));
                                 { word to long }
                                 exprasmlist^.concat(new(pai68k,op_reg(A_EXT,S_L,destreg)));
                                end;
                        u32bit:
                            exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_L,location.register,destreg)));
                        s32bit:
                            exprasmlist^.concat(new(pai68k,op_reg_reg(A_MOVE,S_L,location.register,destreg)));
                    end;
                    if delloc then
                        ungetregister(location.register);
                end;
            LOC_REFERENCE:
                begin
                    r:=newreference(location.reference);
                    case orddef^.typ of
                        u8bit: begin
                                 exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_L,r,destreg)));
                                 exprasmlist^.concat(new(pai68k,op_const_reg(A_ANDI,S_L,$FF,destreg)));
                               end;
                        s8bit:  begin
                                 exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_B,r,destreg)));
                                 if (opt_processors <> MC68020) then
                                  begin
                                 { byte to word }
                                     exprasmlist^.concat(new(pai68k,op_reg(A_EXT,S_W,destreg)));
                                 { word to long }
                                     exprasmlist^.concat(new(pai68k,op_reg(A_EXT,S_L,destreg)));
                                  end
                                 else { 68020+ and later only }
                                     exprasmlist^.concat(new(pai68k,op_reg(A_EXTB,S_L,destreg)));
                                end;
                        u16bit: begin
                                 exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_W,r,destreg)));
                                 exprasmlist^.concat(new(pai68k,op_const_reg(A_ANDI,S_L,$ffff,destreg)));
                                end;
                        s16bit: begin
                                       exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_W,r,destreg)));
                                 { word to long }
                                 exprasmlist^.concat(new(pai68k,op_reg(A_EXT,S_L,destreg)));
                                end;
                        u32bit:
                            exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_L,r,destreg)));
                        s32bit:
                            exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_L,r,destreg)));
                    end;
                    if delloc then
                        del_reference(location.reference);
                end
            else
                internalerror(6);
        end;
    end;


    { if necessary A5 is reloaded after a call}
    procedure maybe_loada5;

      var
         hp : preference;
         p : pprocinfo;
         i : longint;

      begin
         if assigned(procinfo._class) then
           begin
              if lexlevel>2 then
                begin
                   new(hp);
                   reset_reference(hp^);
                   hp^.offset:=procinfo.framepointer_offset;
                   hp^.base:=procinfo.framepointer;
                   exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_L,hp,R_A5)));
                   p:=procinfo.parent;
                   for i:=3 to lexlevel-1 do
                     begin
                        new(hp);
                        reset_reference(hp^);
                        hp^.offset:=p^.framepointer_offset;
                        hp^.base:=R_A5;
                        exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_L,hp,R_A5)));
                        p:=p^.parent;
                     end;
                   new(hp);
                   reset_reference(hp^);
                   hp^.offset:=p^.ESI_offset;
                   hp^.base:=R_A5;
                   exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_L,hp,R_A5)));
                end
              else
                begin
                   new(hp);
                   reset_reference(hp^);
                   hp^.offset:=procinfo.ESI_offset;
                   hp^.base:=procinfo.framepointer;
                   exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_L,hp,R_A5)));
                end;
           end;
      end;


  (***********************************************************************)
  (* PROCEDURE FLOATLOAD                                                 *)
  (*  Description: This routine is to be called each time a location     *)
  (*   must be set to LOC_FPU and a value loaded into a FPU register.    *)
  (*                                                                     *)
  (*  Remark: The routine sets up the register field of LOC_FPU correctly*)
  (***********************************************************************)

    procedure floatload(t : tfloattype;const ref : treference; var location:tlocation);

      var
         op : tasmop;
         s : topsize;

      begin
        { no emulation }
        case t of
            s32real : s := S_S;
            s64real : s := S_Q;
            s80real : s := S_X;
         else
           begin
             Message(cg_f_unknown_float_type);
           end;
        end; { end case }
        location.loc := LOC_FPU;
        if not ((cs_fp_emulation) in aktswitches) then
        begin
            location.fpureg := getfloatreg;
            exprasmlist^.concat(new(pai68k,op_ref_reg(A_FMOVE,s,newreference(ref),location.fpureg)))
        end
        else
        { handle emulation }
        begin
          if t = s32real then
          begin
            location.fpureg := getregister32;
            exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVE,S_L,newreference(ref),location.fpureg)))
          end
          else
             { other floating types are not supported in emulation mode }
            Message(sym_e_type_id_not_defined);
        end;
      end;

{    procedure floatstoreops(t : tfloattype;var op : tasmop;var s : topsize);

      begin
         case t of
            s32real : begin
                         op:=A_FSTP;
                         s:=S_S;
                      end;
            s64real : begin
                         op:=A_FSTP;
                         s:=S_L;
                      end;
            s80real : begin
                         op:=A_FSTP;
                         s:=S_Q;
                      end;
            s64bit : begin
                         op:=A_FISTP;
                         s:=S_Q;
                      end;
            else internalerror(17);
         end;
      end; }


    { stores an FPU value to memory }
    { location:tlocation used to free up FPU register }
    { ref: destination of storage                     }
    procedure floatstore(t : tfloattype;var location:tlocation; const ref:treference);

      var
         op : tasmop;
         s : topsize;

      begin
        if location.loc <> LOC_FPU then
         InternalError(34);
        { no emulation }
        case t of
            s32real : s := S_S;
            s64real : s := S_Q;
            s80real : s := S_X;
         else
           begin
             Message(cg_f_unknown_float_type);
           end;
        end; { end case }
        if not ((cs_fp_emulation) in aktswitches) then
        begin
            exprasmlist^.concat(new(pai68k,op_reg_ref(A_FMOVE,s,location.fpureg,newreference(ref))));
            ungetregister(location.fpureg);
        end
        else
        { handle emulation }
        begin
          if t = s32real then
          begin
            exprasmlist^.concat(new(pai68k,op_reg_ref(A_MOVE,S_L,location.fpureg,newreference(ref))));
            ungetregister32(location.fpureg);
          end
          else
             { other floating types are not supported in emulation mode }
            Message(sym_e_type_id_not_defined);
        end;
        location.fpureg:=R_NO;  { no register in LOC_FPU now }
      end;

    procedure firstcomplex(p : ptree);

      var
         hp : ptree;

      begin
         { always calculate boolean AND and OR from left to right }
         if ((p^.treetype=orn) or (p^.treetype=andn)) and
           (p^.left^.resulttype^.deftype=orddef) and
           (porddef(p^.left^.resulttype)^.typ=bool8bit) then
           p^.swaped:=false
         else if (p^.left^.registers32<p^.right^.registers32)

           { the following check is appropriate, because all }
           { 4 registers are rarely used and it is thereby   }
           { achieved that the extra code is being dropped   }
           { by exchanging not commutative operators         }
           and (p^.right^.registers32<=4) then
           begin
              hp:=p^.left;
              p^.left:=p^.right;
              p^.right:=hp;
              p^.swaped:=true;
           end
         else p^.swaped:=false;
      end;

    procedure secondfuncret(var p : ptree);

      var
         hregister : tregister;

      begin
         clear_reference(p^.location.reference);
         p^.location.reference.base:=procinfo.framepointer;
         p^.location.reference.offset:=procinfo.retoffset;
         if ret_in_param(procinfo.retdef) then
           begin
              hregister:=getaddressreg;
              exprasmlist^.concat(new(pai68k,op_ref_reg(A_MOVEA,S_L,newreference(p^.location.reference),hregister)));
              p^.location.reference.base:=hregister;
              p^.location.reference.offset:=0;
           end;
      end;

    procedure codegen_newprocedure;

      begin
         aktbreaklabel:=nil;
         aktcontinuelabel:=nil;
         { aktexitlabel:=0; is store in oldaktexitlabel
           so it must not be reset to zero before this storage !}

         { the type of this lists isn't important }
         { because the code of this lists is      }
         { copied to the code segment             }
         procinfo.aktentrycode:=new(paasmoutput,init);
         procinfo.aktexitcode:=new(paasmoutput,init);
         procinfo.aktproccode:=new(paasmoutput,init);
      end;

    procedure codegen_doneprocedure;

      begin
         dispose(procinfo.aktentrycode,done);
         dispose(procinfo.aktexitcode,done);
         dispose(procinfo.aktproccode,done);
      end;

    procedure codegen_newmodule;

      begin
         exprasmlist:=new(paasmoutput,init);
      end;

    procedure codegen_donemodule;

      begin
         dispose(exprasmlist,done);
         dispose(codesegment,done);
         dispose(bsssegment,done);
         dispose(datasegment,done);
         dispose(debuglist,done);
         dispose(externals,done);
         dispose(consts,done);
      end;

  end.
{
  $Log$
  Revision 1.1  1998-03-25 11:18:13  root
  Initial revision

  Revision 1.15  1998/03/22 12:45:38  florian
    * changes of Carl-Eric to m68k target commit:
      - wrong nodes because of the new string cg in intel, I had to create
        this under m68k also ... had to work it out to fix potential alignment
        problems --> this removes the crash of the m68k compiler.
      - added absolute addressing in m68k assembler (required for Amiga startup)
      - fixed alignment problems (because of byte return values, alignment
        would not be always valid) -- is this ok if i change the offset if odd in
        setfirsttemp ?? -- it seems ok...

  Revision 1.14  1998/03/10 04:20:37  carl
    * extdebug problems
    - removed loadstring as it is not required for the m68k

  Revision 1.13  1998/03/10 01:17:16  peter
    * all files have the same header
    * messages are fully implemented, EXTDEBUG uses Comment()
    + AG... files for the Assembler generation

  Revision 1.12  1998/03/09 10:44:35  peter
    + string='', string<>'', string:='', string:=char optimizes (the first 2
      were already in cg68k2)

  Revision 1.11  1998/03/06 00:52:03  peter
    * replaced all old messages from errore.msg, only ExtDebug and some
      Comment() calls are left
    * fixed options.pas

  Revision 1.10  1998/03/03 04:12:04  carl
    * moved generate routines to this unit

  Revision 1.9  1998/03/02 01:48:17  peter
    * renamed target_DOS to target_GO32V1
    + new verbose system, merged old errors and verbose units into one new
      verbose.pas, so errors.pas is obsolete

  Revision 1.8  1998/02/13 10:34:45  daniel
  * Made Motorola version compilable.
  * Fixed optimizer

  Revision 1.7  1998/02/12 11:49:50  daniel
  Yes! Finally! After three retries, my patch!

  Changes:

  Complete rewrite of psub.pas.
  Added support for DLL's.
  Compiler requires less memory.
  Platform units for each platform.

  Revision 1.6  1998/01/11 03:39:02  carl
  * bugfix of concatcopy , was using wrong reference
  * bugfix of MOVEQ

  Revision 1.3  1997/12/09 13:30:05  carl
  + renamed some stuff

  Revision 1.2  1997/12/03 13:59:01  carl
  + added emitcall as in i386 version.

  Revision 1.1.1.1  1997/11/27 08:32:53  michael
  FPC Compiler CVS start


  Pre-CVS log:

  CEC   Carl-Eric Codere
  FK    Florian Klaempfl
  PM    Pierre Muller
  +     feature added
  -     removed
  *     bug fixed or changed

  History:
  27th september 1997:
    + first version for MC68000 (using v093 template) (CEC)
  9th october 1997:
    * fixed a bug in push_int as well as other routines which used
      getregister32 while they are not supposed to (because of how
      the allocation of registers work in parser.pas) (CEC)
    * Fixed some bugs in the concatcopy routine, was allocating
      registers which were not supposed to be allocated. (CEC)

}