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224 lines
9.8 KiB
ObjectPascal
224 lines
9.8 KiB
ObjectPascal
{
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Copyright (c) 1998-2002 by Jonas Maebe, member of the Free Pascal
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Development Team
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This unit implements the ARM optimizer object
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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****************************************************************************
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}
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Unit aoptcpu;
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{$i fpcdefs.inc}
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Interface
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uses cpubase, aopt, aoptcpub;
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Type
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TCpuAsmOptimizer = class(TAsmOptimizer)
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{ uses the same constructor as TAopObj }
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procedure PeepHoleOptPass2;override;
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End;
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Implementation
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uses
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aasmbase,aasmtai,aasmcpu;
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function CanBeCond(p : tai) : boolean;
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begin
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result:=(p.typ=ait_instruction) and (taicpu(p).condition=C_None);
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end;
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{ instructions modifying the CPSR can be only the last instruction }
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function MustBeLast(p : tai) : boolean;
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begin
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Result:=(p.typ=ait_instruction) and
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((taicpu(p).opcode in [A_BL,A_BLX,A_CMP,A_CMN,A_SWI,A_TEQ,A_TST]) or
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(taicpu(p).oppostfix=PF_S));
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end;
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procedure TCpuAsmOptimizer.PeepHoleOptPass2;
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var
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p,hp1,hp2: tai;
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l : longint;
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condition : tasmcond;
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hp3: tai;
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{ UsedRegs, TmpUsedRegs: TRegSet; }
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begin
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p := BlockStart;
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{ UsedRegs := []; }
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while (p <> BlockEnd) Do
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begin
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{ UpdateUsedRegs(UsedRegs, tai(p.next)); }
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case p.Typ Of
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Ait_Instruction:
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begin
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case taicpu(p).opcode Of
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A_B:
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if taicpu(p).condition<>C_None then
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begin
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{ check for
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Bxx xxx
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<several instructions>
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xxx:
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}
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l:=0;
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GetNextInstruction(p, hp1);
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while assigned(hp1) and
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(l<=4) and
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CanBeCond(hp1) and
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{ stop on labels }
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not(hp1.typ=ait_label) do
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begin
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inc(l);
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if MustBeLast(hp1) then
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begin
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GetNextInstruction(hp1,hp1);
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break;
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end
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else
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GetNextInstruction(hp1,hp1);
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end;
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if assigned(hp1) then
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begin
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if FindLabel(tasmlabel(taicpu(p).oper[0]^.ref^.symbol),hp1) then
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begin
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if (l<=4) and (l>0) then
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begin
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condition:=inverse_cond(taicpu(p).condition);
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hp2:=p;
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GetNextInstruction(p,hp1);
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p:=hp1;
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repeat
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if hp1.typ=ait_instruction then
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taicpu(hp1).condition:=condition;
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if MustBeLast(hp1) then
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begin
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GetNextInstruction(hp1,hp1);
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break;
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end
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else
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GetNextInstruction(hp1,hp1);
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until not(assigned(hp1)) or
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not(CanBeCond(hp1)) or
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(hp1.typ=ait_label);
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{ wait with removing else GetNextInstruction could
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ignore the label if it was the only usage in the
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jump moved away }
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tasmlabel(taicpu(hp2).oper[0]^.ref^.symbol).decrefs;
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asml.remove(hp2);
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hp2.free;
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continue;
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end;
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end
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else
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begin
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{ check further for
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Bcc xxx
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<several movs 1>
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B yyy
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xxx:
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<several movs 2>
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yyy:
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}
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{ hp2 points to jmp yyy }
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hp2:=hp1;
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{ skip hp1 to xxx }
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GetNextInstruction(hp1, hp1);
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if assigned(hp2) and
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assigned(hp1) and
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(l<=3) and
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(hp2.typ=ait_instruction) and
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(taicpu(hp2).is_jmp) and
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(taicpu(hp2).condition=C_None) and
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{ real label and jump, no further references to the
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label are allowed }
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(tasmlabel(taicpu(p).oper[0]^.ref^.symbol).getrefs=2) and
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FindLabel(tasmlabel(taicpu(p).oper[0]^.ref^.symbol),hp1) then
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begin
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l:=0;
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{ skip hp1 to <several moves 2> }
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GetNextInstruction(hp1, hp1);
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while assigned(hp1) and
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CanBeCond(hp1) do
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begin
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inc(l);
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GetNextInstruction(hp1, hp1);
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end;
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{ hp1 points to yyy: }
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if assigned(hp1) and
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FindLabel(tasmlabel(taicpu(hp2).oper[0]^.ref^.symbol),hp1) then
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begin
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condition:=inverse_cond(taicpu(p).condition);
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GetNextInstruction(p,hp1);
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hp3:=p;
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p:=hp1;
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repeat
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if hp1.typ=ait_instruction then
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taicpu(hp1).condition:=condition;
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GetNextInstruction(hp1,hp1);
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until not(assigned(hp1)) or
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not(CanBeCond(hp1));
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{ hp2 is still at jmp yyy }
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GetNextInstruction(hp2,hp1);
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{ hp2 is now at xxx: }
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condition:=inverse_cond(condition);
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GetNextInstruction(hp1,hp1);
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{ hp1 is now at <several movs 2> }
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repeat
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taicpu(hp1).condition:=condition;
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GetNextInstruction(hp1,hp1);
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until not(assigned(hp1)) or
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not(CanBeCond(hp1)) or
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(hp1.typ=ait_label);
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{
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asml.remove(hp1.next)
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hp1.next.free;
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asml.remove(hp1);
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hp1.free;
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}
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{ remove Bcc }
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tasmlabel(taicpu(hp3).oper[0]^.ref^.symbol).decrefs;
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asml.remove(hp3);
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hp3.free;
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{ remove jmp }
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tasmlabel(taicpu(hp2).oper[0]^.ref^.symbol).decrefs;
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asml.remove(hp2);
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hp2.free;
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continue;
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end;
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end;
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end;
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end;
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end;
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end;
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end;
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end;
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p := tai(p.next)
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end;
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end;
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begin
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casmoptimizer:=TCpuAsmOptimizer;
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End.
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