cpu.pas

delphi编制的nes模拟器－－tNes

                inc(cycles, 4);
                inc(pc, 2);
            end;

  //*                                       *
  //*       lda instruction 2005/12/30      *
  //*---------------end---------------------*


  //*                                       *
  //*       lda instruction 2005/12/30      *
  //*---------------start-------------------*
        $AD: //absolute
            begin

				taddr:=abaddress(pc);
				a := memread(taddr);
{$IFDEF debug}
				curIns := 'LDA $ ' + intToHex(taddr, 0);
{$ENDIF}
				


                setnz(a);

                inc(cycles, 4);
                inc(pc, 3);


            end;

  //*                                       *
  //*       lda instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       lda instruction 2005/12/30      *
  //*---------------start-------------------*
        $BD: //absolute,x
            begin


				taddr:=iabaddress(pc,x);
				a := memread(taddr);

{$IFDEF debug}
				curIns := 'LDA $' + intToHex(taddr-x, 0) + ',X ';
{$ENDIF}

				setnz(a);

                inc(cycles, 4);
                inc(pc, 3);
            end;

  //*                                       *
  //*       lda instruction 2005/12/30      *
  //*---------------end---------------------*


  //*                                       *
  //*       lda instruction 2005/12/30      *
  //*---------------start-------------------*
        $B9: //absolute,y
            begin

				taddr:=iabaddress(pc,y);
				a := memread(taddr);
{$IFDEF debug}
				curIns := 'LDA $' + intToHex(taddr-y, 0) + ',Y ';
{$ENDIF}


                setnz(a);

                inc(cycles, 4);
                inc(pc, 3);
            end;

  //*                                       *
  //*       lda instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       lda instruction 2005/12/30      *
  //*---------------start-------------------*
        $A1: //indirect,x
            begin
{$IFDEF debug}
                curIns := 'LDA ($' + intToHex(memread(pc + 1), 0) + ',X) ';
{$ENDIF}


				a := memread(IIXaddress(pc,x));


                setnz(a);

                inc(cycles, 6);
                inc(pc, 2);
            end;

  //*                                       *
  //*       lda instruction 2005/12/30      *
  //*---------------end---------------------*


  //*                                       *
  //*       lda instruction 2005/12/30      *
  //*---------------start-------------------*
        $B1: //(indirect),y
            begin
{$IFDEF debug}
                curIns := 'LDA ($' + intToHex(memread(pc + 1), 0) + '),Y ';
{$ENDIF}


                a :=memread(iiyaddress(pc,y));
                setnz(a);

                inc(cycles, 5);
                inc(pc, 2);

            end;

  //*                                       *
  //*       lda instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       ldx instruction 2005/12/30      *
  //*---------------start-------------------*
        $A2: //immediate
            begin
{$IFDEF debug}
                curIns := 'LDX #$' + intToHex(memread(pc + 1), 0);
{$ENDIF}

                x := memread(pc + 1);

                setnz(x);

                inc(cycles, 2);
                inc(pc, 2);
            end;

  //*                                       *
  //*       ldx instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       ldx instruction 2005/12/30      *
  //*---------------start-------------------*
        $A6: //zero page
			begin
				taddr:=zpaddress(pc,);
				x := memread(taddr);
{$IFDEF debug}
				curIns := 'LDX $' + intToHex(taddr, 0);
{$ENDIF}

				

                setnz(x);

                inc(cycles, 3);
                inc(pc, 2);
            end;

  //*                                       *
  //*       ldx instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       ldx instruction 2005/12/30      *
  //*---------------start-------------------*
		$B6: //zero page,y
			begin
				taddr:=izpaddress(pc,y);
				x:=memread(taddr);
{$IFDEF debug}
                curIns := 'LDX $' + intToHex(memread(pc + 1), 0) + ',Y ';
{$ENDIF}

				setnz(x);

                inc(cycles, 4);
                inc(pc, 2);

            end;

  //*                                       *
  //*       ldx instruction 2005/12/30      *
  //*---------------end---------------------*


  //*                                       *
  //*       ldx instruction 2005/12/30      *
  //*---------------start-------------------*
        $AE: //absolute
            begin



				taddr:=abaddress(pc);
				x:=memread(taddr);

{$IFDEF debug}
				curIns := 'LDX $' + intToHex(taddr, 0);
{$ENDIF}
                setnz(x);

                inc(cycles, 4);
                inc(pc, 3);

            end;

  //*                                       *
  //*       ldx instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       ldx instruction 2005/12/30      *
  //*---------------start-------------------*
        $BE: //absolute,y
            begin


				taddr:=iabaddress(pc,y);
				x := memread(taddr);

{$IFDEF debug}
                curIns := 'LDX $' + intToHex(taddr-y, 0) + ',Y';
{$ENDIF}

                setnz(x);

                inc(cycles, 4);
                inc(pc, 3);

            end;

  //*                                       *
  //*       ldx instruction 2005/12/30      *
  //*---------------end---------------------*


  //*                                       *
  //*       ldy instruction 2005/12/30      *
  //*---------------start-------------------*
        $A0: //immediate
            begin
{$IFDEF debug}
                curIns := 'LDY #$' + intToHex(memread(pc + 1), 0);
{$ENDIF}

                y := memread(pc + 1);
                setnz(y);

                inc(cycles, 2);
                inc(pc, 2);

            end;

  //*                                       *
  //*       ldy instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       ldy instruction 2005/12/30      *
  //*---------------start-------------------*
        $A4: //zero page
			begin
				taddr:=zpaddress(pc);
				y:=memread(taddr);
{$IFDEF debug}
				curIns := 'LDY $' + intToHex(taddr, 0);
{$ENDIF}


                setnz(y);

                inc(cycles, 3);
                inc(pc, 2);
            end;

  //*                                       *
  //*       ldy instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       ldy instruction 2005/12/30      *
  //*---------------start-------------------*
		$B4: //zero page,x
            begin
{$IFDEF debug}
                curIns := 'LDY $' + intToHex(memread(pc + 1), 0) + ',X ';
{$ENDIF}

				taddr:=izpaddress(pc,x);
				y:=memread(taddr);
				
                setnz(y);

                inc(cycles, 4);
                inc(pc, 2);
            end;

  //*                                       *
  //*       ldy instruction 2005/12/30      *
  //*---------------end---------------------*


  //*                                       *
  //*       ldy instruction 2005/12/30      *
  //*---------------start-------------------*
        $AC: //absolute
            begin


				taddr:=abaddress(pc);
				y := memread(taddr);

{$IFDEF debug}
                curIns := 'LDY $' + intToHex(taddr, 0);
{$ENDIF}

                setnz(y);

                inc(cycles, 4);
                inc(pc, 3);

            end;

  //*                                       *
  //*       ldy instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       ldy instruction 2005/12/30      *
  //*---------------start-------------------*
        $BC: //absolute,x
            begin


				taddr:=iabaddress(pc,x);
				y := memread(taddr);

{$IFDEF debug}
                curIns := 'LDY $' + intToHex(taddr-x, 0) + ',X';
{$ENDIF}
                setnz(y);

                inc(cycles, 4);
                inc(pc, 3);

            end;

  //*                                       *
  //*       ldy instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       lsr instruction 2005/12/30      *
  //*---------------start-------------------*
        $4A: // accumulator
            begin
{$IFDEF debug}
                curIns := 'LSR ' + intToHex(memread(pc + 1), 0);
{$ENDIF}

                ps.cf := a and $1;
				a := a shr 1;
				setnz(a);

				inc(cycles, 2);
				inc(pc);
			end;
  //*                                       *
  //*       lsr instruction 2005/12/30      *
  //*---------------end---------------------*





 //*                                       *
  //*       lsr instruction 2005/12/30      *
  //*---------------start-------------------*
		$46: //zero page
			begin
				taddr:=zpaddress(pc);
				tempbyte:=memread(taddr);
{$IFDEF debug}
				curIns := 'LSR $' + intToHex(taddr, 0);
{$ENDIF}


				ps.cf := tempbyte and $1;
				tempbyte := tempbyte shr 1;
				setnz(tempbyte);

				memwrite(taddr, tempbyte);

				inc(cycles, 5);
				inc(pc, 2);
			end;
  //*                                       *
  //*       lsr instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       lsr instruction 2005/12/30      *
  //*---------------start-------------------*
		$56: //zero page.x
			begin

				taddr:=izpaddress(pc,x);
				tempbyte:=memread(taddr);

{$IFDEF debug}
				curIns := 'LSR $' + intToHex(memread(pc + 1), 0) + ',X ';
{$ENDIF}


                ps.cf := tempbyte and $1;
				tempbyte := tempbyte shr 1;
				setnz(tempbyte);

                memwrite(taddr, tempbyte);

				inc(cycles, 6);
				inc(pc, 2);
			end;
  //*                                       *
  //*       lsr instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       lsr instruction 2005/12/30      *
  //*---------------start-------------------*
		$4E: //absolute
			begin

				taddr:=abaddress(pc);
				tempbyte:=memread(taddr);
{$IFDEF debug}
				curIns := 'LSR $' + intToHex(taddr, 0);
{$ENDIF}

				ps.cf := tempbyte and $1;
				tempbyte := tempbyte shr 1;
				setnz(tempbyte);

                memwrite(taddr, tempbyte);

                inc(cycles, 6);
				inc(pc, 3);
            end;
  //*                                       *
  //*       lsr instruction 2005/12/30      *
  //*---------------end---------------------*

  //*                                       *
  //*       lsr instruction 2005/12/30      *
  //*---------------start-------------------*
        $5E: //absolute.x
			begin

				taddr:=iabaddress(pc,x);
				tempbyte:=memread(taddr);

{$IFDEF debug}
				curIns := 'LSR $' + intToHex(taddr-x, 0) + ',X ';
{$ENDIF}

				ps.cf := tempbyte and $1;

				tempbyte := tempbyte shr 1;
				setnz(tempbyte);

				memwrite(taddr, tempbyte);

				inc(cycles, 7);
				inc(pc, 3);
			end;
  //*                                       *
  //*       lsr instruction 2005/12/30      *
  //*---------------end---------------------*

  

  //*       nop instruction 2005/12/30      *
  //*---------------start-------------------*
		$EA: // implied
			begin
{$IFDEF debug}
				curIns := 'NOP ';
{$ENDIF}
                inc(cycles, 2);
                inc(pc);
            end;
  //*                                       *
  //*       nop instruction 2005/12/30      *
  //*---------------end---------------------*


  //*                                       *
  //*       ora instruction 2005/12/31      *
  //*---------------start-------------------*
        $09: //immediate
            begin
{$IFDEF debug}
                curIns := 'ORA #$' + intToHex(memread(pc + 1), 0);
{$ENDIF}

                tempbyte := memread(pc + 1);
                a := tempbyte or a;
                setnz(a);

                inc(cycles, 2);
                inc(pc, 2);
            end;

  //*                                       *
  //*       ora instruction 2005/12/31      *
  //*---------------end---------------------*

  //*                                       *