BizHawk/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Vic.cs

using System;
using System.Drawing;

namespace BizHawk.Emulation.Cores.Computers.Commodore64
{
	sealed public partial class Vic
	{
		public Func<int, byte> ReadColorRam;
		public Func<int, byte> ReadMemory;

		public bool ReadAECBuffer() { return pinAEC; }
		public bool ReadBABuffer() { return pinBA; }
		public bool ReadIRQBuffer() { return pinIRQ; }

		int cyclesPerSec;
		int irqShift;
		int[][] pipeline;
		int totalCycles;
		int totalLines;

		public Vic(int newCycles, int newLines, int[][] newPipeline, int newCyclesPerSec, int hblankStart, int hblankEnd, int vblankStart, int vblankEnd)
		{
			{
				this.hblankStart = hblankStart;
				this.hblankEnd = hblankEnd;
				this.vblankStart = vblankStart;
				this.vblankEnd = vblankEnd;

				totalCycles = newCycles;
				totalLines = newLines;
				pipeline = newPipeline;
				cyclesPerSec = newCyclesPerSec;

				bufWidth = TimingBuilder_ScreenWidth(pipeline[0], hblankStart, hblankEnd);
				bufHeight = TimingBuilder_ScreenHeight(vblankStart, vblankEnd, newLines);

				buf = new int[bufWidth * bufHeight];
				bufLength = buf.Length;

				sprites = new SpriteGenerator[8];
				for (int i = 0; i < 8; i++)
					sprites[i] = new SpriteGenerator();

				bufferC = new int[40];
				bufferG = new int[40];
			}
		}

		public int CyclesPerFrame
		{
			get
			{
				return (totalCycles * totalLines);
			}
		}

		public int CyclesPerSecond
		{
			get
			{
				return cyclesPerSec;
			}
		}

		public void ExecutePhase1()
		{
			//xScroll = 1;
			{
				// raster IRQ compare
				if ((cycle == rasterIrqLineXCycle && rasterLine > 0) || (cycle == rasterIrqLine0Cycle && rasterLine == 0))
				{
					if (rasterLine != lastRasterLine)
						if (rasterLine == rasterInterruptLine)
							intRaster = true;
					lastRasterLine = rasterLine;
				}

				// display enable compare
				if (rasterLine == 0x030)
					badlineEnable |= displayEnable;

				// badline compare
				if (badlineEnable && rasterLine >= 0x030 && rasterLine < 0x0F7 && ((rasterLine & 0x7) == yScroll))
				{
					badline = true;
				}
				else
				{
					badline = false;
				}

				// go into display state on a badline
				if (badline)
					idle = false;

				// process some sprite crunch vars
				foreach (SpriteGenerator spr in sprites)
					if (!spr.yExpand) spr.yCrunch = true;

				ParseCycle();

				//xOffset = 0;
				Render();

				// if the BA counter is nonzero, allow CPU bus access
				UpdateBA();
				pinAEC = false;

				// must always come last
				//UpdatePins();
			}
		}

		public void ExecutePhase2()
		{

			{
				ParseCycle();

				// advance cycle and optionally raster line
				cycle++;
				if (cycle == totalCycles)
				{
					if (rasterLine == borderB)
						borderOnVertical = true;
					if (rasterLine == borderT && displayEnable)
						borderOnVertical = false;

					if (rasterLine == vblankStart)
						vblank = true;
					if (rasterLine == vblankEnd)
						vblank = false;

					cycleIndex = 0;
					cycle = 0;
					rasterLine++;
					if (rasterLine == totalLines)
					{
						rasterLine = 0;
						vcbase = 0;
						vc = 0;
					}
				}

				Render();
				UpdateBA();
				pinAEC = (baCount > 0);

				// must always come last
				UpdatePins();
			}
		}

		private void UpdateBA()
		{
			if (pinBA)
				baCount = baResetCounter;
			else if (baCount > 0)
				baCount--;
		}

		private void UpdateBorder()
		{
			borderL = columnSelect ? 0x018 : 0x01F;
			borderR = columnSelect ? 0x158 : 0x14F;
			//borderL = columnSelect ? 28 : 35;
			//borderR = columnSelect ? 348 : 339;
			borderT = rowSelect ? 0x033 : 0x037;
			borderB = rowSelect ? 0x0FB : 0x0F7;
		}

		private void UpdatePins()
		{
			bool irqTemp = !(
				(enableIntRaster & intRaster) |
				(enableIntSpriteDataCollision & intSpriteDataCollision) |
				(enableIntSpriteCollision & intSpriteCollision) |
				(enableIntLightPen & intLightPen));

			irqShift <<= 1;
			irqShift |= (irqTemp ? 0x1 : 0x0);
			pinIRQ = (irqShift & 0x1) != 0;
		}

		private void UpdateVideoMode()
		{
			if (!extraColorMode && !bitmapMode && !multicolorMode)
			{
				videoMode = VicVideoMode.Mode000;
				return;
			}
			else if (!extraColorMode && !bitmapMode && multicolorMode)
			{
				videoMode = VicVideoMode.Mode001;
				return;
			}
			else if (!extraColorMode && bitmapMode && !multicolorMode)
			{
				videoMode = VicVideoMode.Mode010;
				return;
			}
			else if (!extraColorMode && bitmapMode && multicolorMode)
			{
				videoMode = VicVideoMode.Mode011;
				return;
			}
			else if (extraColorMode && !bitmapMode && !multicolorMode)
			{
				videoMode = VicVideoMode.Mode100;
				return;
			}
			videoMode = VicVideoMode.ModeBad;
		}
	}
}