freepascal.compiler/compiler/ppcgen/cgppc.pas

{
    Copyright (c) 2006 by Florian Klaempfl

    This unit implements the common part of the code generator for the PowerPC

    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 cgppc;

{$i fpcdefs.inc}

  interface

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

    type
      tcgppcgen = class(tcg)
        procedure a_param_const(list: TAsmList; size: tcgsize; a: aint; const paraloc : tcgpara); override;
        procedure a_paramaddr_ref(list : TAsmList;const r : treference;const paraloc : tcgpara); override;

        procedure a_call_reg(list : TAsmList;reg: tregister); override;
        procedure a_call_ref(list : TAsmList;ref: treference); override;

        { stores the contents of register reg to the memory location described by
        ref }
        procedure a_load_reg_ref(list: TAsmList; fromsize, tosize: TCGSize;
          reg: tregister; const ref: treference); override;

        procedure a_loadaddr_ref_reg(list : TAsmList;const ref : treference;r : 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;

        { overflow checking }
        procedure g_overflowcheck(list: TAsmList; const l: tlocation; def: tdef);override;

        { entry code }
        procedure g_profilecode(list: TAsmList); override;

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

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

        procedure g_maybe_got_init(list: TAsmList); override;
       protected
        function  get_darwin_call_stub(const s: string): tasmsymbol;
        procedure a_load_subsetref_regs_noindex(list: TAsmList; subsetsize: tcgsize; loadbitsize: byte; const sref: tsubsetreference; valuereg, extra_value_reg: tregister); override;
        { Make sure ref is a valid reference for the PowerPC and sets the }
        { base to the value of the index if (base = R_NO).                }
        { Returns true if the reference contained a base, index and an    }
        { offset or symbol, in which case the base will have been changed }
        { to a tempreg (which has to be freed by the caller) containing   }
        { the sum of part of the original reference                       }
        function  fixref(list: TAsmList; var ref: treference): boolean;
        { contains the common code of a_load_reg_ref and a_load_ref_reg }
        procedure a_load_store(list:TAsmList;op: tasmop;reg:tregister;ref: treference);virtual;

        { creates the correct branch instruction for a given combination }
        { of asmcondflags and destination addressing mode                }
        procedure a_jmp(list: TAsmList; op: tasmop;
                        c: tasmcondflag; crval: longint; l: tasmlabel);

        { returns true if the offset of the given reference can not be  }
        { represented by a 16 bit immediate as required by some PowerPC }
        { instructions                                                  }
        function hasLargeOffset(const ref : TReference) : Boolean; inline;

        function save_lr_in_prologue: boolean;

        function load_got_symbol(list : TAsmList; symbol : string) : tregister;
     end;

  const
    TOpCmp2AsmCond: Array[topcmp] of TAsmCondFlag = (C_NONE,C_EQ,C_GT,
                         C_LT,C_GE,C_LE,C_NE,C_LE,C_LT,C_GE,C_GT);


  implementation

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


    function tcgppcgen.hasLargeOffset(const ref : TReference) : Boolean;
      begin
        result := aword(ref.offset-low(smallint)) > high(smallint)-low(smallint);
      end;


    function tcgppcgen.save_lr_in_prologue: boolean;
      begin
        result:=
        (not (po_assembler in current_procinfo.procdef.procoptions) and
         ((pi_do_call in current_procinfo.flags) or 
          (cs_profile in init_settings.moduleswitches)))  or
        ([cs_lineinfo,cs_debuginfo] * current_settings.moduleswitches <> []);
      end;


    procedure tcgppcgen.a_param_const(list: TAsmList; size: tcgsize; a: aint; const
      paraloc: tcgpara);
    var
      ref: treference;
    begin
      paraloc.check_simple_location;
      case paraloc.location^.loc of
        LOC_REGISTER, LOC_CREGISTER:
          a_load_const_reg(list, size, a, paraloc.location^.register);
        LOC_REFERENCE:
          begin
            reference_reset(ref);
            ref.base := paraloc.location^.reference.index;
            ref.offset := paraloc.location^.reference.offset;
            a_load_const_ref(list, size, a, ref);
          end;
      else
        internalerror(2002081101);
      end;
    end;


    procedure tcgppcgen.a_paramaddr_ref(list : TAsmList;const r : treference;const paraloc : tcgpara);
      var
        ref: treference;
        tmpreg: tregister;

      begin
        paraloc.check_simple_location;
        case paraloc.location^.loc of
           LOC_REGISTER,LOC_CREGISTER:
             a_loadaddr_ref_reg(list,r,paraloc.location^.register);
           LOC_REFERENCE:
             begin
               reference_reset(ref);
               ref.base := paraloc.location^.reference.index;
               ref.offset := paraloc.location^.reference.offset;
               tmpreg := rg[R_INTREGISTER].getregister(list,R_SUBWHOLE);
               a_loadaddr_ref_reg(list,r,tmpreg);
               a_load_reg_ref(list,OS_ADDR,OS_ADDR,tmpreg,ref);
             end;
           else
             internalerror(2002080701);
        end;
      end;


    procedure tcgppcgen.g_maybe_got_init(list: TAsmList);
      var
         instr: taicpu;
         cond: tasmcond;
        savedlr: boolean;
      begin
        if not(po_assembler in current_procinfo.procdef.procoptions) then
          begin
            if (cs_create_pic in current_settings.moduleswitches) and
               (pi_needs_got in current_procinfo.flags) then
              case target_info.system of
                system_powerpc_darwin,
                system_powerpc64_darwin:
                  begin
                    savedlr:=save_lr_in_prologue;
                    if not savedlr then
                      list.concat(taicpu.op_reg_reg(A_MFSPR,NR_R0,NR_LR));
                    fillchar(cond,sizeof(cond),0);
                    cond.simple:=false;
                    cond.bo:=20;
                    cond.bi:=31;
                    instr:=taicpu.op_sym(A_BCL,current_procinfo.CurrGOTLabel);
                    instr.setcondition(cond);
                    list.concat(instr);
                    a_label(list,current_procinfo.CurrGOTLabel);
                    a_reg_alloc(list,current_procinfo.got);
                    list.concat(taicpu.op_reg_reg(A_MFSPR,current_procinfo.got,NR_LR));
                    if not savedlr or
                       { in the following case lr is saved, but not restored }
                       { (happens e.g. when generating debug info for leaf   }
                       { procedures)                                         }
                       not(pi_do_call in current_procinfo.flags) then
                      list.concat(taicpu.op_reg_reg(A_MTSPR,NR_LR,NR_R0));
                  end;
              end;
          end;
      end;


    function tcgppcgen.get_darwin_call_stub(const s: string): tasmsymbol;
      var
        stubname: string;
        instr: taicpu;
        href: treference;
        l1: tasmsymbol;
        localgotlab: tasmlabel;
        cond: tasmcond;
        stubalign: byte;
      begin
        { function declared in the current unit? }
        { doesn't work correctly, because this will also return a hit if we }
        { previously took the address of an external procedure. It doesn't  }
        { really matter, the linker will remove all unnecessary stubs.      }
        stubname := 'L'+s+'$stub';
        result := current_asmdata.getasmsymbol(stubname);
        if assigned(result) then
          exit;

        if current_asmdata.asmlists[al_imports]=nil then
          current_asmdata.asmlists[al_imports]:=TAsmList.create;

        current_asmdata.asmlists[al_imports].concat(Tai_section.create(sec_stub,'',0));
        if (cs_create_pic in current_settings.moduleswitches) then
          stubalign:=32
        else
          stubalign:=16;
        current_asmdata.asmlists[al_imports].concat(Tai_align.Create(stubalign));
        result := current_asmdata.RefAsmSymbol(stubname);
        current_asmdata.asmlists[al_imports].concat(Tai_symbol.Create(result,0));
        current_asmdata.asmlists[al_imports].concat(tai_directive.create(asd_indirect_symbol,s));
        l1 := current_asmdata.RefAsmSymbol('L'+s+'$lazy_ptr');
        reference_reset_symbol(href,l1,0);
        href.refaddr := addr_higha;
        if (cs_create_pic in current_settings.moduleswitches) then
          begin
            current_asmdata.getjumplabel(localgotlab);
            href.relsymbol:=localgotlab;
            fillchar(cond,sizeof(cond),0);
            cond.simple:=false;
            cond.bo:=20;
            cond.bi:=31;
            current_asmdata.asmlists[al_imports].concat(taicpu.op_reg(A_MFLR,NR_R0));
            instr:=taicpu.op_sym(A_BCL,localgotlab);
            instr.setcondition(cond);
            current_asmdata.asmlists[al_imports].concat(instr);
            a_label(current_asmdata.asmlists[al_imports],localgotlab);
            current_asmdata.asmlists[al_imports].concat(taicpu.op_reg(A_MFLR,NR_R11));
            current_asmdata.asmlists[al_imports].concat(taicpu.op_reg_reg_ref(A_ADDIS,NR_R11,NR_R11,href));
            current_asmdata.asmlists[al_imports].concat(taicpu.op_reg(A_MTLR,NR_R0));
          end
        else
          current_asmdata.asmlists[al_imports].concat(taicpu.op_reg_ref(A_LIS,NR_R11,href));
        href.refaddr := addr_low;
        href.base := NR_R11;
{$ifndef cpu64bit}
        current_asmdata.asmlists[al_imports].concat(taicpu.op_reg_ref(A_LWZU,NR_R12,href));
{$else cpu64bit}
        { darwin/ppc64 uses a 32 bit absolute address here, strange... }
        current_asmdata.asmlists[al_imports].concat(taicpu.op_reg_ref(A_LDU,NR_R12,href));
{$endif cpu64bit}
        current_asmdata.asmlists[al_imports].concat(taicpu.op_reg(A_MTCTR,NR_R12));
        current_asmdata.asmlists[al_imports].concat(taicpu.op_none(A_BCTR));
        current_asmdata.asmlists[al_imports].concat(tai_directive.create(asd_lazy_symbol_pointer,''));
        current_asmdata.asmlists[al_imports].concat(Tai_symbol.Create(l1,0));
        current_asmdata.asmlists[al_imports].concat(tai_directive.create(asd_indirect_symbol,s));
        current_asmdata.asmlists[al_imports].concat(tai_const.createname('dyld_stub_binding_helper',0));
      end;


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

       var
         ref2, tmpref: treference;

       begin
         ref2 := ref;
         fixref(list,ref2);
         if assigned(ref2.symbol) then
           begin
             if target_info.system = system_powerpc_macos then
               begin
                 if macos_direct_globals then
                   begin
                     reference_reset(tmpref);
                     tmpref.offset := ref2.offset;
                     tmpref.symbol := ref2.symbol;
                     tmpref.base := NR_NO;
                     list.concat(taicpu.op_reg_reg_ref(A_ADDI,r,NR_RTOC,tmpref));
                   end
                 else
                   begin
                     reference_reset(tmpref);
                     tmpref.symbol := ref2.symbol;
                     tmpref.offset := 0;
                     tmpref.base := NR_RTOC;
                     list.concat(taicpu.op_reg_ref(A_LWZ,r,tmpref));

                     if ref2.offset <> 0 then
                       begin
                         reference_reset(tmpref);
                         tmpref.offset := ref2.offset;
                         tmpref.base:= r;
                         list.concat(taicpu.op_reg_ref(A_LA,r,tmpref));
                       end;
                   end;

                 if ref2.base <> NR_NO then
                   list.concat(taicpu.op_reg_reg_reg(A_ADD,r,r,ref2.base));

                 //list.concat(tai_comment.create(strpnew('*** a_loadaddr_ref_reg')));
               end
             else
               begin

                 { add the symbol's value to the base of the reference, and if the }
                 { reference doesn't have a base, create one                       }
                 reference_reset(tmpref);
                 tmpref.offset := ref2.offset;
                 tmpref.symbol := ref2.symbol;
                 tmpref.relsymbol := ref2.relsymbol;
                 tmpref.refaddr := addr_higha;
                 if ref2.base<> NR_NO then
                   begin
                     list.concat(taicpu.op_reg_reg_ref(A_ADDIS,r,
                       ref2.base,tmpref));
                   end
                 else
                   list.concat(taicpu.op_reg_ref(A_LIS,r,tmpref));
                 tmpref.base := NR_NO;
                 tmpref.refaddr := addr_low;
                 { can be folded with one of the next instructions by the }
                 { optimizer probably                                     }
                 list.concat(taicpu.op_reg_reg_ref(A_ADDI,r,r,tmpref));
               end
           end
         else if ref2.offset <> 0 Then
           if ref2.base <> NR_NO then
             a_op_const_reg_reg(list,OP_ADD,OS_ADDR,ref2.offset,ref2.base,r)
           { FixRef makes sure that "(ref.index <> R_NO) and (ref.offset <> 0)" never}
           { occurs, so now only ref.offset has to be loaded                         }
           else
             a_load_const_reg(list,OS_ADDR,ref2.offset,r)
         else if ref2.index <> NR_NO Then
           list.concat(taicpu.op_reg_reg_reg(A_ADD,r,ref2.base,ref2.index))
         else if (ref2.base <> NR_NO) and
                 (r <> ref2.base) then
           a_load_reg_reg(list,OS_ADDR,OS_ADDR,ref2.base,r)
         else
           list.concat(taicpu.op_reg_const(A_LI,r,0));
       end;



    { calling a procedure by address }
    procedure tcgppcgen.a_call_reg(list : TAsmList;reg: tregister);
      begin
        list.concat(taicpu.op_reg(A_MTCTR,reg));
        list.concat(taicpu.op_none(A_BCTRL));
        include(current_procinfo.flags,pi_do_call);
      end;


    procedure tcgppcgen.a_call_ref(list : TAsmList;ref: treference);
      var
        tempreg : TRegister;
      begin
        tempreg := getintregister(list, OS_ADDR);
        a_load_ref_reg(list,OS_ADDR,OS_ADDR,ref,tempreg);
        a_call_reg(list,tempreg);
      end;


    procedure tcgppcgen.a_load_reg_ref(list: TAsmList; fromsize, tosize: TCGSize;
      reg: tregister; const ref: treference);

    const
      StoreInstr: array[OS_8..OS_INT, boolean, boolean] of TAsmOp =
      { indexed? updating?}
      (((A_STB, A_STBU), (A_STBX, A_STBUX)),
        ((A_STH, A_STHU), (A_STHX, A_STHUX)),
        ((A_STW, A_STWU), (A_STWX, A_STWUX))
{$ifdef cpu64bit}
        ,
        ((A_STD, A_STDU), (A_STDX, A_STDUX))
{$endif cpu64bit}
        );
    var
      op: TAsmOp;
      ref2: TReference;
    begin
      if not (fromsize in [OS_8..OS_INT,OS_S8..OS_SINT]) then
        internalerror(2002090903);
      if not (tosize in [OS_8..OS_INT,OS_S8..OS_SINT]) then
        internalerror(2002090905);

      ref2 := ref;
      fixref(list, ref2);
      if tosize in [OS_S8..OS_SINT] then
        { storing is the same for signed and unsigned values }
        tosize := tcgsize(ord(tosize) - (ord(OS_S8) - ord(OS_8)));
      op := storeinstr[tcgsize2unsigned[tosize], ref2.index <> NR_NO, false];
      a_load_store(list, op, reg, ref2);
    end;



     procedure tcgppcgen.a_loadfpu_reg_reg(list: TAsmList; fromsize, tosize: tcgsize; reg1, reg2: tregister);

       var
         op: tasmop;
         instr: taicpu;
       begin
         if not(fromsize in [OS_F32,OS_F64]) or
            not(tosize in [OS_F32,OS_F64]) then
           internalerror(2006123110);
         if (tosize < fromsize) then
           op:=A_FRSP
         else
           op:=A_FMR;
         instr := taicpu.op_reg_reg(op,reg2,reg1);
         list.concat(instr);
         if (op = A_FMR) then
           rg[R_FPUREGISTER].add_move_instruction(instr);
       end;


     procedure tcgppcgen.a_loadfpu_ref_reg(list: TAsmList; fromsize, tosize: tcgsize; const ref: treference; reg: tregister);

       const
         FpuLoadInstr: Array[OS_F32..OS_F64,boolean, boolean] of TAsmOp =
                          { indexed? updating?}
                    (((A_LFS,A_LFSU),(A_LFSX,A_LFSUX)),
                     ((A_LFD,A_LFDU),(A_LFDX,A_LFDUX)));
       var
         op: tasmop;
         ref2: treference;

       begin
         if not(fromsize in [OS_F32,OS_F64]) or
            not(tosize in [OS_F32,OS_F64]) then
           internalerror(200201121);
         ref2 := ref;
         fixref(list,ref2);
         op := fpuloadinstr[fromsize,ref2.index <> NR_NO,false];
         a_load_store(list,op,reg,ref2);
         if (fromsize > tosize) then
           a_loadfpu_reg_reg(list,fromsize,tosize,reg,reg);
       end;


     procedure tcgppcgen.a_loadfpu_reg_ref(list: TAsmList; fromsize, tosize: tcgsize; reg: tregister; const ref: treference);

       const
         FpuStoreInstr: Array[OS_F32..OS_F64,boolean, boolean] of TAsmOp =
                            { indexed? updating?}
                    (((A_STFS,A_STFSU),(A_STFSX,A_STFSUX)),
                     ((A_STFD,A_STFDU),(A_STFDX,A_STFDUX)));
       var
         op: tasmop;
         ref2: treference;
{$ifndef cpu64bit}
         reg2: tregister;
{$endif cpu64bit}

       begin
         if not(fromsize in [OS_F32,OS_F64]) or
            not(tosize in [OS_F32,OS_F64]) then
           internalerror(200201122);
         ref2 := ref;
         fixref(list,ref2);
         op := fpustoreinstr[tosize,ref2.index <> NR_NO,false];
{$ifndef cpu64bit}
         { some ppc's have a bug whereby storing a double to memory }
         { as single corrupts the value -> convert double to single }
         { first                                                    }
         if (tosize < fromsize) then
           begin
             reg2:=getfpuregister(list,tosize);
             a_loadfpu_reg_reg(list,fromsize,tosize,reg,reg2);
             reg:=reg2;
           end;
{$endif not cpu64bit}
         a_load_store(list,op,reg,ref2);
       end;


  procedure tcgppcgen.a_load_subsetref_regs_noindex(list: TAsmList; subsetsize: tcgsize; loadbitsize: byte; const sref: tsubsetreference; valuereg, extra_value_reg: tregister);
    var
      fromsreg, tosreg: tsubsetregister;
      restbits: byte;
    begin
      restbits := (sref.bitlen - (loadbitsize - sref.startbit));
      if (subsetsize in [OS_S8..OS_S128]) then
        begin
         { sign extend }
         a_op_const_reg(list,OP_SHL,OS_INT,AIntBits-loadbitsize+sref.startbit,valuereg);
         a_op_const_reg(list,OP_SAR,OS_INT,AIntBits-sref.bitlen,valuereg);
        end
      else
        begin
          a_op_const_reg(list,OP_SHL,OS_INT,restbits,valuereg);
          { mask other bits }
          if (sref.bitlen <> AIntBits) then
            a_op_const_reg(list,OP_AND,OS_INT,(aword(1) shl sref.bitlen)-1,valuereg);
        end;
      { use subsetreg routine, it may have been overridden with an optimized version }
      fromsreg.subsetreg := extra_value_reg;
      fromsreg.subsetregsize := OS_INT;
      { subsetregs always count bits from right to left }
      fromsreg.startbit := loadbitsize-restbits;
      fromsreg.bitlen := restbits;

      tosreg.subsetreg := valuereg;
      tosreg.subsetregsize := OS_INT;
      tosreg.startbit := 0;
      tosreg.bitlen := restbits;

      a_load_subsetreg_subsetreg(list,subsetsize,subsetsize,fromsreg,tosreg);
    end;


  procedure tcgppcgen.g_overflowcheck(list: TAsmList; const l: tlocation; def: tdef);
    var
      hl : tasmlabel;
      flags : TResFlags;
    begin
      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,
                                        bool8bit,bool16bit,bool32bit,bool64bit]))) then
        begin
          if (current_settings.optimizecputype >= cpu_ppc970) or
             (current_settings.cputype >= cpu_ppc970) then
            begin
              { ... instructions setting overflow flag ...
              mfxerf R0
              mtcrf 128, R0
              ble cr0, label }
              list.concat(taicpu.op_reg(A_MFXER, NR_R0));
              list.concat(taicpu.op_const_reg(A_MTCRF, 128, NR_R0));
              flags.cr := RS_CR0;
              flags.flag := F_LE;
              a_jmp_flags(list, flags, hl);
            end
          else
            begin
              list.concat(taicpu.op_reg(A_MCRXR,NR_CR7));
              a_jmp(list,A_BC,C_NO,7,hl)
            end;
        end
      else
        a_jmp_cond(list,OC_AE,hl);
      a_call_name(list,'FPC_OVERFLOW');
      a_label(list,hl);
    end;


  procedure tcgppcgen.g_profilecode(list: TAsmList);
    var
      paraloc1 : tcgpara;
    begin
      if (target_info.system in [system_powerpc_darwin]) then
        begin
          paraloc1.init;
          paramanager.getintparaloc(pocall_cdecl,1,paraloc1);
          a_param_reg(list,OS_ADDR,NR_R0,paraloc1);
          paramanager.freeparaloc(list,paraloc1);
          paraloc1.done;
          allocallcpuregisters(list);
          a_call_name(list,'mcount');
          deallocallcpuregisters(list);
          a_reg_dealloc(list,NR_R0);
        end;
    end;


  procedure tcgppcgen.a_jmp_cond(list : TAsmList;cond : TOpCmp; l: tasmlabel);
    begin
      a_jmp(list,A_BC,TOpCmp2AsmCond[cond],0,l);
    end;


 procedure tcgppcgen.a_jmp(list: TAsmList; op: tasmop; c: tasmcondflag;
             crval: longint; l: tasmlabel);
   var
     p: taicpu;

   begin
     p := taicpu.op_sym(op,l);
     if op <> A_B then
       create_cond_norm(c,crval,p.condition);
     p.is_jmp := true;
     list.concat(p)
   end;



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

        procedure loadvmttor11;
        var
          href : treference;
        begin
          reference_reset_base(href,NR_R3,0);
          cg.a_load_ref_reg(list,OS_ADDR,OS_ADDR,href,NR_R11);
        end;


        procedure op_onr11methodaddr;
        var
          href : treference;
        begin
          if (procdef.extnumber=$ffff) then
            Internalerror(200006139);
          { call/jmp  vmtoffs(%eax) ; method offs }
          reference_reset_base(href,NR_R11,procdef._class.vmtmethodoffset(procdef.extnumber));
          if hasLargeOffset(href) then
            begin
{$ifdef cpu64}
              if (longint(href.offset) <> href.offset) then
                { add support for offsets > 32 bit }
                internalerror(200510201);
{$endif cpu64}
              list.concat(taicpu.op_reg_reg_const(A_ADDIS,NR_R11,NR_R11,
                smallint((href.offset shr 16)+ord(smallint(href.offset and $ffff) < 0))));
              href.offset := smallint(href.offset and $ffff);
            end;
          a_load_ref_reg(list,OS_ADDR,OS_ADDR,href,NR_R11);
          if (target_info.system = system_powerpc64_linux) then
            begin
              reference_reset_base(href, NR_R11, 0);
              a_load_ref_reg(list, OS_ADDR, OS_ADDR, href, NR_R11);
            end;
          list.concat(taicpu.op_reg(A_MTCTR,NR_R11));
          list.concat(taicpu.op_none(A_BCTR));
          if (target_info.system = system_powerpc64_linux) then
            list.concat(taicpu.op_none(A_NOP));
        end;


      var
        make_global : boolean;
      begin
        if not(procdef.proctypeoption in [potype_function,potype_procedure]) then
          Internalerror(200006137);
        if not assigned(procdef._class) or
           (procdef.procoptions*[po_classmethod, po_staticmethod,
             po_methodpointer, po_interrupt, po_iocheck]<>[]) then
          Internalerror(200006138);
        if procdef.owner.symtabletype<>ObjectSymtable then
          Internalerror(200109191);

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

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

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

        { case 4 }
        if po_virtualmethod in procdef.procoptions then
          begin
            loadvmttor11;
            op_onr11methodaddr;
          end
        { case 0 }
        else
          case target_info.system of
            system_powerpc_darwin,
            system_powerpc64_darwin:
              list.concat(taicpu.op_sym(A_B,get_darwin_call_stub(procdef.mangledname)));
            system_powerpc64_linux:
              {$note ts:todo add GOT change?? - think not needed :) }
              list.concat(taicpu.op_sym(A_B,current_asmdata.RefAsmSymbol('.' + procdef.mangledname)));
            else
              list.concat(taicpu.op_sym(A_B,current_asmdata.RefAsmSymbol(procdef.mangledname)))
          end;
        List.concat(Tai_symbol_end.Createname(labelname));
      end;


    function tcgppcgen.load_got_symbol(list: TAsmList; symbol : string) : tregister;
    var
      l: tasmsymbol;
      ref: treference;
    begin
      if (target_info.system <> system_powerpc64_linux) then
        internalerror(2007102010);
      l:=current_asmdata.getasmsymbol(symbol);
      reference_reset_symbol(ref,l,0);
      ref.base := NR_R2;
      ref.refaddr := addr_pic;
    
      result := rg[R_INTREGISTER].getregister(list, R_SUBWHOLE);
      {$IFDEF EXTDEBUG}
      list.concat(tai_comment.create(strpnew('loading got reference for ' + symbol)));
      {$ENDIF EXTDEBUG}
    //  cg.a_load_ref_reg(list,OS_ADDR,OS_ADDR,ref,result);
      
{$ifdef cpu64bit}
      list.concat(taicpu.op_reg_ref(A_LD, result, ref));
{$else cpu64bit}
      list.concat(taicpu.op_reg_ref(A_LWZ, result, ref));
{$endif cpu64bit}
    end;
    
    
    function tcgppcgen.fixref(list: TAsmList; var ref: treference): boolean;
      var
        tmpreg: tregister;
      begin
        result := false;

        { Avoid recursion. }
        if (ref.refaddr = addr_pic) then
          exit;

        {$IFDEF EXTDEBUG}
        list.concat(tai_comment.create(strpnew('fixref0 ' + ref2string(ref))));
        {$ENDIF EXTDEBUG}
        if (target_info.system in [system_powerpc_darwin,system_powerpc64_darwin]) and
           assigned(ref.symbol) and
           not assigned(ref.relsymbol) and
           ((ref.symbol.bind = AB_EXTERNAL) or
            (cs_create_pic in current_settings.moduleswitches))then
          begin
            if (ref.symbol.bind = AB_EXTERNAL) or
               ((cs_create_pic in current_settings.moduleswitches) and
                (ref.symbol.bind in [AB_COMMON,AB_GLOBAL])) then
              begin
                tmpreg := g_indirect_sym_load(list,ref.symbol.name);
                ref.symbol:=nil;
              end
            else
              begin
                include(current_procinfo.flags,pi_needs_got);
                tmpreg := current_procinfo.got;
                if assigned(ref.relsymbol) then
                  internalerror(2007093501);
                ref.relsymbol := current_procinfo.CurrGOTLabel;
              end;
            if (ref.base = NR_NO) then
              ref.base := tmpreg
            else if (ref.index = NR_NO) then
              ref.index := tmpreg
            else
              begin
                list.concat(taicpu.op_reg_reg_reg(A_ADD,tmpreg,ref.base,tmpreg));
                ref.base := tmpreg;
              end;
          end;

        { if we have to create PIC, add the symbol to the TOC/GOT }
        if (target_info.system = system_powerpc64_linux) and
           (cs_create_pic in current_settings.moduleswitches) and 
           (assigned(ref.symbol)) then
          begin
            tmpreg := load_got_symbol(list, ref.symbol.name);
            if (ref.base = NR_NO) then
              ref.base := tmpreg
            else if (ref.index = NR_NO) then
              ref.index := tmpreg
            else begin
              a_op_reg_reg_reg(list, OP_ADD, OS_ADDR, ref.base, tmpreg, tmpreg);
              ref.base := tmpreg;
            end;
            ref.symbol := nil;
            {$IFDEF EXTDEBUG}
            list.concat(tai_comment.create(strpnew('fixref-pic ' + ref2string(ref))));
            {$ENDIF EXTDEBUG}
          end;

        if (ref.base = NR_NO) then
          begin
            ref.base := ref.index;
            ref.index := NR_NO;
          end;
        if (ref.base <> NR_NO) then
          begin
            if (ref.index <> NR_NO) and
               ((ref.offset <> 0) or assigned(ref.symbol)) then
              begin
                result := true;
                tmpreg := rg[R_INTREGISTER].getregister(list,R_SUBWHOLE);
                list.concat(taicpu.op_reg_reg_reg(
                  A_ADD,tmpreg,ref.base,ref.index));
                ref.index := NR_NO;
                ref.base := tmpreg;
              end
          end;
        if (ref.index <> NR_NO) and
           (assigned(ref.symbol) or
            (ref.offset <> 0)) then
          internalerror(200208102);
        {$IFDEF EXTDEBUG}
        list.concat(tai_comment.create(strpnew('fixref1 ' + ref2string(ref))));
        {$ENDIF EXTDEBUG}
       end;


    procedure tcgppcgen.a_load_store(list:TAsmList;op: tasmop;reg:tregister;
       ref: treference);

      var
        tmpreg: tregister;
        tmpref: treference;
        largeOffset: Boolean;

      begin
        tmpreg := NR_NO;
        largeOffset:= hasLargeOffset(ref);

        if target_info.system = system_powerpc_macos then
          begin

            if assigned(ref.symbol) then
              begin {Load symbol's value}
                tmpreg := rg[R_INTREGISTER].getregister(list,R_SUBWHOLE);

                reference_reset(tmpref);
                tmpref.symbol := ref.symbol;
                tmpref.base := NR_RTOC;

                if macos_direct_globals then
                  list.concat(taicpu.op_reg_ref(A_LA,tmpreg,tmpref))
                else
                  list.concat(taicpu.op_reg_ref(A_LWZ,tmpreg,tmpref));
              end;

            if largeOffset then
              begin {Add hi part of offset}
                reference_reset(tmpref);

                if Smallint(Lo(ref.offset)) < 0 then
                  tmpref.offset := Hi(ref.offset) + 1 {Compensate when lo part is negative}
                else
                  tmpref.offset := Hi(ref.offset);

                if (tmpreg <> NR_NO) then
                  list.concat(taicpu.op_reg_reg_ref(A_ADDIS,tmpreg, tmpreg,tmpref))
                else
                  begin
                    tmpreg := rg[R_INTREGISTER].getregister(list,R_SUBWHOLE);
                    list.concat(taicpu.op_reg_ref(A_LIS,tmpreg,tmpref));
                  end;
              end;

            if (tmpreg <> NR_NO) then
              begin
                {Add content of base register}
                if ref.base <> NR_NO then
                  list.concat(taicpu.op_reg_reg_reg(A_ADD,tmpreg,
                    ref.base,tmpreg));

                {Make ref ready to be used by op}
                ref.symbol:= nil;
                ref.base:= tmpreg;
                if largeOffset then
                  ref.offset := Smallint(Lo(ref.offset));

                list.concat(taicpu.op_reg_ref(op,reg,ref));
                //list.concat(tai_comment.create(strpnew('*** a_load_store indirect global')));
              end
            else
              list.concat(taicpu.op_reg_ref(op,reg,ref));
          end
        else {if target_info.system <> system_powerpc_macos}
          begin
            if assigned(ref.symbol) or
               largeOffset then
              begin
                tmpreg := rg[R_INTREGISTER].getregister(list,R_SUBWHOLE);
                reference_reset(tmpref);
                tmpref.symbol := ref.symbol;
                tmpref.relsymbol := ref.relsymbol;
                tmpref.offset := ref.offset;
                tmpref.refaddr := addr_higha;
                if ref.base <> NR_NO then
                  list.concat(taicpu.op_reg_reg_ref(A_ADDIS,tmpreg,
                    ref.base,tmpref))
                else
                  list.concat(taicpu.op_reg_ref(A_LIS,tmpreg,tmpref));
                ref.base := tmpreg;
                ref.refaddr := addr_low;
                list.concat(taicpu.op_reg_ref(op,reg,ref));
              end
            else
              list.concat(taicpu.op_reg_ref(op,reg,ref));
          end;
      end;


end.