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184 lines
7.3 KiB
ObjectPascal
184 lines
7.3 KiB
ObjectPascal
{
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Copyright (c) 1998-2014 by the Free Pascal development team
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This unit calls the optimization procedures to optimize the assembler
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code 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 aoptcpu;
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{$i fpcdefs.inc}
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{$define DEBUG_AOPTCPU}
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Interface
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uses
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cpubase, aoptobj, aoptcpub, aopt, aasmtai;
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Type
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TCpuAsmOptimizer = class(TAsmOptimizer)
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function PeepHoleOptPass1Cpu(var p: tai): boolean; override;
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{ outputs a debug message into the assembler file }
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procedure DebugMsg(const s: string; p: tai);
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End;
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Implementation
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uses
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cutils, aasmcpu, cgutils;
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{$ifdef DEBUG_AOPTCPU}
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procedure TCpuAsmOptimizer.DebugMsg(const s: string; p : tai);
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begin
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asml.insertbefore(tai_comment.Create(strpnew(s)), p);
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end;
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{$else DEBUG_AOPTCPU}
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procedure TCpuAsmOptimizer.DebugMsg(const s: string; p : tai);inline;
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begin
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end;
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{$endif DEBUG_AOPTCPU}
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function TCpuAsmOptimizer.PeepHoleOptPass1Cpu(var p: tai): boolean;
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var
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next: tai;
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tmpref: treference;
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tmpsingle: single;
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begin
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result:=false;
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case p.typ of
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ait_instruction:
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begin
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//asml.insertbefore(tai_comment.Create(strpnew('pass1 called for instr')), p);
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case taicpu(p).opcode of
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{ LEA (Ax),Ax is a NOP if src and dest reg is equal, so remove it. }
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A_LEA:
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if GetNextInstruction(p,next) and not assigned(taicpu(p).oper[0]^.ref^.symbol) and
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(((taicpu(p).oper[0]^.ref^.base = taicpu(p).oper[1]^.reg) and
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(taicpu(p).oper[0]^.ref^.index = NR_NO)) or
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((taicpu(p).oper[0]^.ref^.index = taicpu(p).oper[1]^.reg) and
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(taicpu(p).oper[0]^.ref^.base = NR_NO))) and
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(taicpu(p).oper[0]^.ref^.offset = 0) then
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begin
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DebugMsg('Optimizer: LEA 0(Ax),Ax removed',p);
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asml.remove(p);
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p.free;
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p:=next;
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result:=true;
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end;
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{ Address register sub/add can be replaced with ADDQ/SUBQ or LEA if the value is in the
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SmallInt range, which is shorter to encode and faster to execute on most 68k }
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A_SUB,A_SUBA,A_ADD,A_ADDA:
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if (taicpu(p).oper[1]^.typ = top_reg) and isaddressregister(taicpu(p).oper[1]^.reg) and
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(taicpu(p).oper[0]^.typ = top_const) then
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begin
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if isvalueforaddqsubq(taicpu(p).oper[0]^.val) then
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begin
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DebugMsg('Optimizer: SUB/ADD #val,Ax to SUBQ/ADDQ',p);
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taicpu(p).opsize:=S_L; // this is safe, because we're targetting an address reg
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if taicpu(p).opcode in [A_ADD,A_ADDA] then
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taicpu(p).opcode:=A_ADDQ
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else
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taicpu(p).opcode:=A_SUBQ;
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result:=true;
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end
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else
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if isvalue16bit(abs(taicpu(p).oper[0]^.val)) then
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begin
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DebugMsg('Optimizer: SUB/ADD #val,Ax to LEA val(Ax),Ax',p);
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if taicpu(p).opcode in [A_SUB,A_SUBA] then
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reference_reset_base(tmpref,taicpu(p).oper[1]^.reg,-taicpu(p).oper[0]^.val,0)
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else
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reference_reset_base(tmpref,taicpu(p).oper[1]^.reg,taicpu(p).oper[0]^.val,0);
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taicpu(p).opcode:=A_LEA;
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taicpu(p).loadref(0,tmpref);
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result:=true;
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end;
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end;
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{ MOVEA #0,Ax to SUBA Ax,Ax, because it's shorter }
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A_MOVEA:
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if (taicpu(p).oper[0]^.typ = top_const) and
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(taicpu(p).oper[0]^.val = 0) then
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begin
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DebugMsg('Optimizer: MOVEA #0,Ax to SUBA Ax,Ax',p);
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taicpu(p).opcode:=A_SUBA;
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taicpu(p).opsize:=S_L; { otherwise it will be .W -> BOOM }
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taicpu(p).loadoper(0,taicpu(p).oper[1]^);
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result:=true;
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end;
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{ CMP #0,<ea> equals to TST <ea>, just shorter and TST is more flexible anyway }
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A_CMP,A_CMPI:
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if (taicpu(p).oper[0]^.typ = top_const) and
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(taicpu(p).oper[0]^.val = 0) then
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begin
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DebugMsg('Optimizer: CMP #0 to TST',p);
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taicpu(p).opcode:=A_TST;
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taicpu(p).loadoper(0,taicpu(p).oper[1]^);
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taicpu(p).clearop(1);
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taicpu(p).ops:=1;
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result:=true;
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end;
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A_FCMP:
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if (taicpu(p).oper[0]^.typ = top_realconst) then
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begin
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if (taicpu(p).oper[0]^.val_real = 0.0) then
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begin
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DebugMsg('Optimizer: FCMP #0.0 to FTST',p);
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taicpu(p).opcode:=A_FTST;
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taicpu(p).opsize:=S_FX;
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taicpu(p).loadoper(0,taicpu(p).oper[1]^);
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taicpu(p).clearop(1);
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taicpu(p).ops:=1;
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result:=true;
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end
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else
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begin
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tmpsingle:=taicpu(p).oper[0]^.val_real;
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if (taicpu(p).opsize = S_FD) and
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((taicpu(p).oper[0]^.val_real - tmpsingle) = 0.0) then
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begin
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DebugMsg('Optimizer: FCMP const to lesser precision',p);
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taicpu(p).opsize:=S_FS;
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result:=true;
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end;
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end;
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end;
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A_FMOVE,A_FMUL,A_FADD,A_FSUB,A_FDIV:
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if (taicpu(p).oper[0]^.typ = top_realconst) then
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begin
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tmpsingle:=taicpu(p).oper[0]^.val_real;
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if (taicpu(p).opsize = S_FD) and
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((taicpu(p).oper[0]^.val_real - tmpsingle) = 0.0) then
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begin
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DebugMsg('Optimizer: FMOVE/FMUL/FADD/FSUB/FDIV const to lesser precision',p);
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taicpu(p).opsize:=S_FS;
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result:=true;
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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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begin
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casmoptimizer:=TCpuAsmOptimizer;
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end.
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