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* MIPS: reworked and fixed procedure fixup_jmps:
* support conditional branches with 2 parameters * factored out common parts * adjusted range limits, they were copy-pasted from PowerPC target which uses 14-bit offsets. MIPS however uses 16-bit offsets, i.e. can branch 4 times farther. git-svn-id: trunk@33088 -
This commit is contained in:
sergei
parent
6ca424900b
commit
e23ed15634
@ -497,16 +497,41 @@ procedure DoneAsm;
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procedure fixup_jmps(list: TAsmList);
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var
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p,pdelayslot: tai;
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newcomment: tai_comment;
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newins,newjmp,newnoop: taicpu;
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newjmp,newnoop: taicpu;
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labelpositions: TFPList;
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instrpos: ptrint;
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l: tasmlabel;
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inserted_something: boolean;
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href: treference;
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again: boolean;
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insai: tai;
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procedure create_pic_load(ai: taicpu; insloc: tai);
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var
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href: treference;
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newins: taicpu;
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begin
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{ validity of operand has been checked by caller }
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href:=ai.oper[ai.ops-1]^.ref^;
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href.refaddr:=addr_pic;
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href.base:=NR_GP;
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newins:=taicpu.op_reg_ref(A_LW,NR_PIC_FUNC,href);
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newins.fileinfo:=ai.fileinfo;
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list.insertbefore(newins,insloc);
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inc(instrpos,2);
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if (href.symbol.bind=AB_LOCAL) then
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begin
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href.refaddr:=addr_low;
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href.base:=NR_NO;
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newins:=taicpu.op_reg_reg_ref(A_ADDIU,NR_PIC_FUNC,NR_PIC_FUNC,href);
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newins.fileinfo:=ai.fileinfo;
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list.insertbefore(newins,insloc);
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inc(instrpos,2);
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end;
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end;
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begin
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// MIPS relative branch range is +-32K instructions, i.e +-128 kBytes
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// if certainly not enough instructions to cause an overflow, dont bother
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if (list.count <= (high(smallint) div 4)) then
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if (list.count<high(smallint)) then
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exit;
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labelpositions := TFPList.create;
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p := tai(list.first);
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@ -538,11 +563,11 @@ procedure fixup_jmps(list: TAsmList);
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end;
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{ If the number of instructions is below limit, we can't overflow either }
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if (instrpos <= (high(smallint) div 4)) then
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if (instrpos<high(smallint)) then
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exit;
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// check and fix distances
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repeat
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inserted_something := false;
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again := false;
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p := tai(list.first);
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instrpos := 1;
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while assigned(p) do
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@ -561,120 +586,76 @@ procedure fixup_jmps(list: TAsmList);
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begin
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inc(instrpos,2);
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case taicpu(p).opcode of
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A_BA:
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if (taicpu(p).oper[0]^.typ = top_ref) and
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assigned(taicpu(p).oper[0]^.ref^.symbol) and
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(taicpu(p).oper[0]^.ref^.symbol is tasmlabel) and
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(labelpositions[tasmlabel(taicpu(p).oper[0]^.ref^.symbol).labelnr] <> NIL) and
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A_BA,A_BC:
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if (taicpu(p).ops>0) and (taicpu(p).oper[taicpu(p).ops-1]^.typ=top_ref) and
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assigned(taicpu(p).oper[taicpu(p).ops-1]^.ref^.symbol) and
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(taicpu(p).oper[taicpu(p).ops-1]^.ref^.symbol is tasmlabel) and
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(labelpositions[tasmlabel(taicpu(p).oper[taicpu(p).ops-1]^.ref^.symbol).labelnr] <> NIL) and
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{$push}
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{$q-}
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(ptruint(abs(ptrint(labelpositions[tasmlabel(taicpu(p).oper[0]^.ref^.symbol).labelnr]-instrpos)) - (low(smallint) div 4)) > ptruint((high(smallint) - low(smallint)) div 4)) then
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(ptruint(abs(ptrint(labelpositions[tasmlabel(taicpu(p).oper[taicpu(p).ops-1]^.ref^.symbol).labelnr]-instrpos)) - low(smallint)) > ptruint((high(smallint) - low(smallint)))) then
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{$pop}
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begin
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if (cs_create_pic in current_settings.moduleswitches) then
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if (taicpu(p).opcode=A_BC) then
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begin
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newcomment:=tai_comment.create(strpnew('fixup_jmps, A_BA changed into PIC sequence'));
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list.insertbefore(newcomment,p);
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href:=taicpu(p).oper[0]^.ref^;
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href.refaddr:=addr_pic;
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href.base:=NR_GP;
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newins:=taicpu.op_reg_ref(A_LW,NR_PIC_FUNC,href);
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newins.fileinfo:=taicpu(p).fileinfo;
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list.insertbefore(newins,p);
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inc(instrpos,2);
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if (href.symbol.bind=AB_LOCAL) then
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begin
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href.refaddr:=addr_low;
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href.base:=NR_NO;
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newins:=taicpu.op_reg_reg_ref(A_ADDIU,NR_PIC_FUNC,NR_PIC_FUNC,href);
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newins.fileinfo:=taicpu(p).fileinfo;
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list.insertbefore(newins,p);
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inc(instrpos,2);
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end;
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taicpu(p).opcode:=A_JR;
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taicpu(p).loadreg(0,NR_PIC_FUNC);
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end
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else
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begin
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taicpu(p).opcode:=A_J;
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newcomment:=tai_comment.create(strpnew('fixup_jmps, A_BA changed into A_J'));
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list.insertbefore(newcomment,p);
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end;
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end;
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A_BC:
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if (taicpu(p).ops=3) and (taicpu(p).oper[2]^.typ = top_ref) and
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assigned(taicpu(p).oper[2]^.ref^.symbol) and
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(taicpu(p).oper[2]^.ref^.symbol is tasmlabel) and
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(labelpositions[tasmlabel(taicpu(p).oper[2]^.ref^.symbol).labelnr] <> NIL) and
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{$push}
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{$q-}
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(ptruint(abs(ptrint(labelpositions[tasmlabel(taicpu(p).oper[2]^.ref^.symbol).labelnr]-instrpos)) - (low(smallint) div 4)) > ptruint((high(smallint) - low(smallint)) div 4)) then
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{$pop}
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begin
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// add a new label after this jump
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current_asmdata.getjumplabel(l);
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{ new label -> may have to increase array size }
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if (l.labelnr >= labelpositions.count) then
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labelpositions.count := l.labelnr + 10;
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{ newjmp will be inserted before the label, and it's inserted after }
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{ plus delay slot }
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{ the current jump -> instrpos+3 }
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labelpositions[l.labelnr] := pointer(instrpos+2*3);
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pdelayslot:=tai(p.next);
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{ We need to insert the new instruction after the delay slot instruction ! }
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while assigned(pdelayslot) and (pdelayslot.typ<>ait_instruction) do
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pdelayslot:=tai(pdelayslot.next);
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{ we're adding a new label together with the only branch to it;
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providing exact label position is not necessary }
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current_asmdata.getjumplabel(l);
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pdelayslot:=tai(p.next);
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{ We need to insert the new instruction after the delay slot instruction ! }
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while assigned(pdelayslot) and (pdelayslot.typ<>ait_instruction) do
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pdelayslot:=tai(pdelayslot.next);
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list.insertafter(tai_label.create(l),pdelayslot);
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// add a new unconditional jump between this jump and the label
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newcomment:=tai_comment.create(strpnew('fixup_jmps, A_BXX changed into A_BNOTXX label;A_J;label:'));
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list.insertbefore(newcomment,p);
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if (cs_create_pic in current_settings.moduleswitches) then
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begin
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reference_reset_symbol(href,taicpu(p).oper[2]^.ref^.symbol,0,sizeof(pint));
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href.refaddr:=addr_pic;
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href.base:=NR_GP;
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newins:=taicpu.op_reg_ref(A_LW,NR_PIC_FUNC,href);
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newins.fileinfo:=taicpu(p).fileinfo;
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list.insertafter(newins,pdelayslot);
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pdelayslot:=newins;
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inc(instrpos,2);
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if (href.symbol.bind=AB_LOCAL) then
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insai:=tai_label.create(l);
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list.insertafter(insai,pdelayslot);
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// add a new unconditional jump between this jump and the label
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list.insertbefore(tai_comment.create(strpnew('fixup_jmps, A_BXX changed into A_BNOTXX label;A_J;label:')),p);
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if (cs_create_pic in current_settings.moduleswitches) then
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begin
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href.base:=NR_NO;
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href.refaddr:=addr_low;
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newins:=taicpu.op_reg_reg_ref(A_ADDIU,NR_PIC_FUNC,NR_PIC_FUNC,href);
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newins.fileinfo:=taicpu(p).fileinfo;
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list.insertafter(newins,pdelayslot);
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pdelayslot:=newins;
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inc(instrpos,2);
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create_pic_load(taicpu(p),insai);
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newjmp:=taicpu.op_reg(A_JR,NR_PIC_FUNC);
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end
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else
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begin
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newjmp:=taicpu.op_sym(A_J,taicpu(p).oper[2]^.ref^.symbol);
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newjmp.is_jmp := true;
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end;
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newjmp:=taicpu.op_reg(A_JR,NR_PIC_FUNC);
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newjmp.fileinfo:=taicpu(p).fileinfo;
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list.insertafter(newjmp,pdelayslot);
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list.insertbefore(newjmp,insai);
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inc(instrpos,2);
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{ Add a delay slot for new A_J instruction }
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newnoop:=taicpu.op_none(A_NOP);
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newnoop.fileinfo := taicpu(p).fileinfo;
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list.insertbefore(newnoop,insai);
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inc(instrpos,2);
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// change the conditional jump to point to the newly inserted label
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tasmlabel(taicpu(p).oper[taicpu(p).ops-1]^.ref^.symbol).decrefs;
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taicpu(p).oper[taicpu(p).ops-1]^.ref^.symbol := l;
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l.increfs;
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// and invert its condition code
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taicpu(p).condition := inverse_cond(taicpu(p).condition);
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{ skip inserted stuff and continue processing from 'pdelayslot' }
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p:=pdelayslot;
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again:=true;
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end
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else
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else // opcode=A_BA
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begin
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newjmp := taicpu.op_sym(A_J,taicpu(p).oper[2]^.ref^.symbol);
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newjmp.is_jmp := true;
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newjmp.fileinfo := taicpu(p).fileinfo;
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list.insertafter(newjmp,pdelayslot);
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inc(instrpos,2);
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if (cs_create_pic in current_settings.moduleswitches) then
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begin
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list.insertbefore(tai_comment.create(strpnew('fixup_jmps, A_BA changed into PIC sequence')),p);
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create_pic_load(taicpu(p),p);
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taicpu(p).opcode:=A_JR;
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taicpu(p).loadreg(0,NR_PIC_FUNC);
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again:=true;
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{ inserted stuff before 'p', continue processing from 'p' on }
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end
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else
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begin
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list.insertbefore(tai_comment.create(strpnew('fixup_jmps, A_BA changed into A_J')),p);
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taicpu(p).opcode:=A_J;
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end;
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end;
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{ Add a delay slot for new A_J instruction }
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newnoop:=taicpu.op_none(A_NOP);
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newnoop.fileinfo := taicpu(p).fileinfo;
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list.insertafter(newnoop,newjmp);
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inc(instrpos,2);
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// change the conditional jump to point to the newly inserted label
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tasmlabel(taicpu(p).oper[2]^.ref^.symbol).decrefs;
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taicpu(p).oper[2]^.ref^.symbol := l;
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l.increfs;
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// and invert its condition code
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taicpu(p).condition := inverse_cond(taicpu(p).condition);
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// we inserted an instruction, so will have to check everything again
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inserted_something := true;
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end;
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end;
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end;
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@ -683,7 +664,7 @@ procedure fixup_jmps(list: TAsmList);
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end;
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p := tai(p.next);
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end;
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until not inserted_something;
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until not again;
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labelpositions.free;
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end;
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