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86 lines
3.0 KiB
ObjectPascal
86 lines
3.0 KiB
ObjectPascal
{
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Copyright (c) 1998-2002 by Florian Klaempfl
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This unit implements the register allocator for m68k
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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 rgcpu;
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{$i fpcdefs.inc}
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interface
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uses
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aasmbase,aasmtai,aasmdata,aasmcpu,
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cgbase,cgutils,cpubase,
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rgobj;
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type
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trgcpu = class(trgobj)
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function do_spill_replace(list:TAsmList;instr:taicpu;orgreg:tsuperregister;const spilltemp:treference):boolean;override;
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end;
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implementation
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{ returns True if source operand of MOVE can be replaced with spilltemp when its destination is ref^. }
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function isvalidmovedest(ref: preference): boolean; inline;
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begin
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{ The following is for Coldfire, for other CPUs it maybe can be relaxed. }
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result:=(ref^.symbol=nil) and (ref^.scalefactor<=1) and
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(ref^.index=NR_NO) and (ref^.base<>NR_NO) and (ref^.offset>=low(smallint)) and
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(ref^.offset<=high(smallint));
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end;
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function trgcpu.do_spill_replace(list:TAsmList;instr:taicpu;orgreg:tsuperregister;const spilltemp:treference):boolean;
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var
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opidx: longint;
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begin
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result:=false;
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opidx:=-1;
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{ TODO: support more instructions (on m68k almost all are eligible) }
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if (not (regtype in [R_INTREGISTER,R_ADDRESSREGISTER])) or (instr.opcode<>A_MOVE) then
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exit;
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if (instr.ops<>2) then
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exit;
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if (instr.oper[0]^.typ=top_reg) and (get_alias(getsupreg(instr.oper[0]^.reg))=orgreg) then
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begin
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{ source can be replaced if dest is register or a 'simple' reference }
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if (instr.oper[1]^.typ=top_reg) or
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((instr.oper[1]^.typ=top_ref) and isvalidmovedest(instr.oper[1]^.ref)) then
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opidx:=0;
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end
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else if (instr.oper[1]^.typ=top_reg) and (get_alias(getsupreg(instr.oper[1]^.reg))=orgreg) and
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(instr.oper[0]^.typ=top_reg) then
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opidx:=1;
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if (opidx<0) then
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exit;
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instr.oper[opidx]^.typ:=top_ref;
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new(instr.oper[opidx]^.ref);
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instr.oper[opidx]^.ref^:=spilltemp;
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case instr.opsize of
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S_B: inc(instr.oper[opidx]^.ref^.offset,3);
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S_W: inc(instr.oper[opidx]^.ref^.offset,2);
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end;
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result:=true;
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end;
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end.
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