{
    Copyright (c) 1998-2002 by Florian Klaempfl and Carl Eric Codere

    Generate PowerPC assembler for in set/case nodes

    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 nppcset;

{$I fpcdefs.inc}

interface

uses
  node, nset, ncgset, cpubase, cgbase, cgobj, aasmbase, aasmtai, globtype;

type

  tppccasenode = class(tcgcasenode)
  protected
    procedure optimizevalues(var max_linear_list : aint; var max_dist : aword); override;

    function has_jumptable : boolean; override;
    procedure genjumptable(hp: pcaselabel; min_, max_ : aint); override;
    procedure genlinearlist(hp: pcaselabel); override;
  end;

implementation

uses
  systems,
  verbose, globals,
  symconst, symdef, defutil,
  paramgr,
  cpuinfo,
  pass_2, cgcpu,
  ncon,
  tgobj, ncgutil, regvars, rgobj, aasmcpu,
  procinfo, cgutils;

{*****************************************************************************
                            TCGCASENODE
*****************************************************************************}

procedure tppccasenode.optimizevalues(var max_linear_list : aint; var max_dist : aword);
begin
  max_linear_list := 10;
end;

function tppccasenode.has_jumptable : boolean;
begin
  has_jumptable := true;
end;

procedure tppccasenode.genjumptable(hp : pcaselabel; min_, max_ : aint);
var
  table : tasmlabel;
  last : TConstExprInt;
  indexreg : tregister;
  href : treference;

  procedure genitem(list:taasmoutput;t : pcaselabel);
  var
    i : aint;
  begin
    if assigned(t^.less) then
      genitem(list,t^.less);
    { fill possible hole }
    for i:=last+1 to t^._low-1 do
      list.concat(Tai_const.Create_sym(elselabel));
    for i:=t^._low to t^._high do
      list.concat(Tai_const.Create_sym(blocklabel(t^.blockid)));
    last:=t^._high;
    if assigned(t^.greater) then
      genitem(list,t^.greater);
  end;

begin
  { this is exactly the same code as for 32 bit PowerPC processors. It might be useful to change this
   later (with e.g. TOC support) into a method which uses relative values in the jumptable to save space
   and memory bandwidth. At the moment this is not a good idea, since these methods involve loading of
   one or more 64 bit integer adresses which is slow }
  if not(jumptable_no_range) then begin
    { case expr less than min_ => goto elselabel }
    cg.a_cmp_const_reg_label(exprasmlist,opsize,jmp_lt,aint(min_),hregister,elselabel);
    { case expr greater than max_ => goto elselabel }
    cg.a_cmp_const_reg_label(exprasmlist,opsize,jmp_gt,aint(max_),hregister,elselabel);
  end;
  objectlibrary.getjumplabel(table);
  { allocate base and index registers register }
  indexreg:= cg.makeregsize(exprasmlist, hregister, OS_INT);
  { indexreg := hregister; }
  cg.a_load_reg_reg(exprasmlist, opsize, OS_INT, hregister, indexreg);
  { create reference, indexreg := indexreg * sizeof(OS_ADDR) }
  cg.a_op_const_reg(exprasmlist, OP_MUL, OS_INT, tcgsize2size[OS_ADDR], indexreg);
  reference_reset_symbol(href, table, (-aint(min_)) * tcgsize2size[OS_ADDR]);
  href.index := indexreg;

  cg.a_load_ref_reg(exprasmlist, OS_INT, OS_INT, href, indexreg);

  exprasmlist.concat(taicpu.op_reg(A_MTCTR, indexreg));
  exprasmlist.concat(taicpu.op_none(A_BCTR));

  { generate jump table }
  new_section(current_procinfo.aktlocaldata,sec_data,current_procinfo.procdef.mangledname,sizeof(aint));
  current_procinfo.aktlocaldata.concat(Tai_label.Create(table));
  last:=min_;
  genitem(current_procinfo.aktlocaldata,hp);
end;

procedure tppccasenode.genlinearlist(hp: pcaselabel);
var
  first, lastrange: boolean;
  last: TConstExprInt;

  procedure genitem(t: pcaselabel);

    procedure gensub(value: aint);
    var
      tmpreg: tregister;
    begin
      value := -value;
      if (value >= low(smallint)) and
        (value <= high(smallint)) then
        exprasmlist.concat(taicpu.op_reg_reg_const(A_ADDIC_, hregister,
          hregister, value))
      else
      begin
        tmpreg := cg.getintregister(exprasmlist, OS_INT);
        cg.a_load_const_reg(exprasmlist, OS_INT, value, tmpreg);
        exprasmlist.concat(taicpu.op_reg_reg_reg(A_ADD_, hregister,
          hregister, tmpreg));
      end;
    end;

  begin
    if assigned(t^.less) then
      genitem(t^.less);
    { need we to test the first value }
    if first and (t^._low > get_min_value(left.resulttype.def)) then begin
      cg.a_cmp_const_reg_label(exprasmlist, OS_INT, jmp_lt, aword(t^._low),
        hregister, elselabel);
    end;
    if t^._low = t^._high then begin
      if t^._low - last = 0 then
        cg.a_cmp_const_reg_label(exprasmlist, opsize, OC_EQ, 0, hregister,
          blocklabel(t^.blockid))
      else
        gensub(aint(t^._low - last));
      tcgppc(cg).a_jmp_cond(exprasmlist, OC_EQ, blocklabel(t^.blockid));
      last := t^._low;
      lastrange := false;
    end else begin
      { it begins with the smallest label, if the value }
      { is even smaller then jump immediately to the    }
      { ELSE-label                                }
      if first then begin
        { have we to ajust the first value ? }
        if (t^._low > get_min_value(left.resulttype.def)) then
          gensub(aint(t^._low));
      end else begin
        { if there is no unused label between the last and the }
        { present label then the lower limit can be checked    }
        { immediately. else check the range in between:       }
        gensub(aint(t^._low - last));
        if ((t^._low - last) <> 1) or (not lastrange) then
          tcgppc(cg).a_jmp_cond(exprasmlist, jmp_lt, elselabel);
      end;
      gensub(aint(t^._high - t^._low));
      tcgppc(cg).a_jmp_cond(exprasmlist, jmp_le, blocklabel(t^.blockid));
      last := t^._high;
      lastrange := true;
    end;
    first := false;
    if assigned(t^.greater) then
      genitem(t^.greater);
  end;

begin
  { do we need to generate cmps? }
  if (with_sign and (min_label < 0)) or (opsize = OS_32) then
    genlinearcmplist(hp)
  else begin
    last := 0;
    lastrange := false;
    first := true;
    genitem(hp);
    cg.a_jmp_always(exprasmlist, elselabel);
  end;
end;

begin
  ccasenode := tppccasenode;
end.