253 lines
7.0 KiB
C#
253 lines
7.0 KiB
C#
//http://nesdev.parodius.com/bbs/viewtopic.php?p=4571&sid=db4c7e35316cc5d734606dd02f11dccb
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using System;
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using System.Runtime.CompilerServices;
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using BizHawk.Common;
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namespace BizHawk.Emulation.Cores.Nintendo.NES
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{
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public sealed partial class PPU
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{
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// this only handles region differences within the PPU
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int preNMIlines;
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int postNMIlines;
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bool chopdot;
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public enum Region { NTSC, PAL, Dendy, RGB };
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Region _region;
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public Region region { set { _region = value; SyncRegion(); } get { return _region; } }
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void SyncRegion()
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{
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switch (region)
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{
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case Region.NTSC:
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preNMIlines = 1; postNMIlines = 20; chopdot = true; break;
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case Region.PAL:
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preNMIlines = 1; postNMIlines = 70; chopdot = false; break;
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case Region.Dendy:
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preNMIlines = 51; postNMIlines = 20; chopdot = false; break;
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case Region.RGB:
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preNMIlines = 1; postNMIlines = 20; chopdot = false; break;
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}
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}
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public class DebugCallback
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{
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public int Scanline;
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//public int Dot; //not supported
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public Action Callback;
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}
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public DebugCallback NTViewCallback;
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public DebugCallback PPUViewCallback;
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// true = light sensed
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public bool LightGunCallback(int x, int y)
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{
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// the actual light gun circuit is very complex
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// and this doesn't do it justice at all, as expected
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const int radius = 10; // look at pixel values up to this far away, roughly
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int sum = 0;
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int ymin = Math.Max(Math.Max(y - radius, ppur.status.sl - 20), 0);
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int ymax = Math.Min(y + radius, 239);
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int xmin = Math.Max(x - radius, 0);
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int xmax = Math.Min(x + radius, 255);
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int ystop = ppur.status.sl - 2;
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int xstop = ppur.status.cycle - 20;
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for (int j = ymin; j <= ymax; j++)
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{
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for (int i = xmin; i <= xmax; i++)
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{
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if (j >= ystop && i >= xstop || j > ystop)
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goto loopout;
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short s = xbuf[j * 256 + i];
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int lum = s & 0x30;
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if ((s & 0x0f) >= 0x0e)
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lum = 0;
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sum += lum;
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}
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}
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loopout:
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return sum >= 2000;
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}
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//when the ppu issues a write it goes through here and into the game board
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public void ppubus_write(int addr, byte value)
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{
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nes.Board.AddressPPU(addr);
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nes.Board.WritePPU(addr, value);
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}
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//when the ppu issues a read it goes through here and into the game board
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public byte ppubus_read(int addr, bool ppu)
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{
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//hardware doesnt touch the bus when the PPU is disabled
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if (!reg_2001.PPUON && ppu)
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return 0xFF;
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nes.Board.AddressPPU(addr);
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return nes.Board.ReadPPU(addr);
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}
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//debug tools peek into the ppu through this
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public byte ppubus_peek(int addr)
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{
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return nes.Board.PeekPPU(addr);
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}
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public enum PPUPHASE
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{
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VBL, BG, OBJ
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};
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public PPUPHASE ppuphase;
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private readonly NES nes;
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public PPU(NES nes)
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{
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this.nes = nes;
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OAM = new byte[0x100];
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PALRAM = new byte[0x20];
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//power-up palette verified by blargg's power_up_palette test.
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//he speculates that these may differ depending on the system tested..
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//and I don't see why the ppu would waste any effort setting these..
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//but for the sake of uniformity, we'll do it.
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Array.Copy(new byte[] {
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0x09,0x01,0x00,0x01,0x00,0x02,0x02,0x0D,0x08,0x10,0x08,0x24,0x00,0x00,0x04,0x2C,
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0x09,0x01,0x34,0x03,0x00,0x04,0x00,0x14,0x08,0x3A,0x00,0x02,0x00,0x20,0x2C,0x08
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}, PALRAM, 0x20);
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Reset();
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}
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public void NESSoftReset()
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{
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//this hasn't been brought up to date since NEShawk was first made.
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//in particular http://wiki.nesdev.com/w/index.php/PPU_power_up_state should be studied, but theres no use til theres test cases
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Reset();
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}
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//state
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int ppudead; //measured in frames
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bool idleSynch;
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int NMI_PendingInstructions;
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byte PPUGenLatch;
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bool vtoggle;
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byte VRAMBuffer;
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public byte[] OAM;
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public byte[] PALRAM;
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public void SyncState(Serializer ser)
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{
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ser.Sync("ppudead", ref ppudead);
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ser.Sync("idleSynch", ref idleSynch);
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ser.Sync("NMI_PendingInstructions", ref NMI_PendingInstructions);
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ser.Sync("PPUGenLatch", ref PPUGenLatch);
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ser.Sync("vtoggle", ref vtoggle);
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ser.Sync("VRAMBuffer", ref VRAMBuffer);
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ser.Sync("ppu_addr_temp", ref ppu_addr_temp);
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ser.Sync("Read_Value", ref read_value);
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ser.Sync("Prev_soam_index", ref soam_index_prev);
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ser.Sync("Spr_Zero_Go", ref sprite_zero_go);
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ser.Sync("Spr_zero_in_Range", ref sprite_zero_in_range);
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ser.Sync("Is_even_cycle", ref is_even_cycle);
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ser.Sync("soam_index", ref soam_index);
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ser.Sync("ppu_open_bus", ref ppu_open_bus);
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ser.Sync("double_2007_read", ref double_2007_read);
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ser.Sync("ppu_open_bus_decay_timer", ref ppu_open_bus_decay_timer, false);
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ser.Sync("OAM", ref OAM, false);
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ser.Sync("PALRAM", ref PALRAM, false);
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ser.Sync("Reg2002_objoverflow", ref Reg2002_objoverflow);
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ser.Sync("Reg2002_objhit", ref Reg2002_objhit);
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ser.Sync("Reg2002_vblank_active", ref Reg2002_vblank_active);
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ser.Sync("Reg2002_vblank_active_pending", ref Reg2002_vblank_active_pending);
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ser.Sync("Reg2002_vblank_clear_pending", ref Reg2002_vblank_clear_pending);
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ppur.SyncState(ser);
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byte temp8 = reg_2000.Value; ser.Sync("reg_2000.Value", ref temp8); reg_2000.Value = temp8;
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temp8 = reg_2001.Value; ser.Sync("reg_2001.Value", ref temp8); reg_2001.Value = temp8;
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ser.Sync("reg_2003", ref reg_2003);
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//don't sync framebuffer into binary (rewind) states
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if(ser.IsText)
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ser.Sync("xbuf", ref xbuf, false);
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}
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public void Reset()
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{
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regs_reset();
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ppudead = 2;
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idleSynch = true;
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ppu_open_bus = 0;
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ppu_open_bus_decay_timer = new int[8];
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}
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#if VS2012
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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#endif
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void TriggerNMI()
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{
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nes.cpu.NMI = true;
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}
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//this gets called once after each cpu instruction executes.
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//anything that needs to happen at instruction granularity can get checked here
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//to save having to check it at ppu cycle granularity
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public void PostCpuInstructionOne()
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{
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if (NMI_PendingInstructions > 0)
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{
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NMI_PendingInstructions--;
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if (NMI_PendingInstructions <= 0)
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{
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TriggerNMI();
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}
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}
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}
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#if VS2012
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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#endif
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void runppu(int x)
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{
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//run one ppu cycle at a time so we can interact with the ppu and clockPPU at high granularity
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for (int i = 0; i < x; i++)
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{
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ppur.status.cycle++;
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is_even_cycle = !is_even_cycle;
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//might not actually run a cpu cycle if there are none to be run right now
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nes.RunCpuOne();
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if (Reg2002_vblank_active_pending)
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{
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//if (Reg2002_vblank_active_pending)
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Reg2002_vblank_active = 1;
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Reg2002_vblank_active_pending = false;
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}
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if (Reg2002_vblank_clear_pending)
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{
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Reg2002_vblank_active = 0;
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Reg2002_vblank_clear_pending = false;
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}
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nes.Board.ClockPPU();
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}
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}
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//hack
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//public bool PAL = false;
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//bool SPRITELIMIT = true;
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}
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}
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