c64- rewrote video code, more accurate scanline behavior
This commit is contained in:
saxxonpike
parent
513793a177
commit
30c0564bda
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@ -480,9 +480,11 @@ namespace BizHawk.Emulation.Computers.Commodore64
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public int borderRight;
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public int borderTop;
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public int characterColumn;
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public byte characterData;
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public int characterIndex;
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public byte[] characterMemory;
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public bool charactersEnabled;
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public byte colorData;
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public byte[] colorMemory;
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public int cycle;
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public int cycleLeft;
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@ -499,7 +501,9 @@ namespace BizHawk.Emulation.Computers.Commodore64
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public int renderOffset;
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public byte[,] spriteData;
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public int spriteFetchCycle;
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public int spriteFetchIndex;
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public ushort[] spritePointers;
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public int spriteFetchStartCycle;
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public VicIITask task;
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public int totalCycles;
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public bool vBlank;
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@ -530,13 +534,13 @@ namespace BizHawk.Emulation.Computers.Commodore64
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rasterTotalLines = 263;
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rasterLineLeft = 0x19C;
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cycleLeft = 0;
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spriteFetchCycle = 58;
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spriteFetchCycle = 59;
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visibleLeft = 0x008;
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visibleRight = 0x168;
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visibleTop = 0x023; //0x041;
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visibleBottom = 0x004; //0x013;
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visibleRenderX = false;
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visibleRenderY = true;
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visibleRenderY = false;
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visibleWidth = 352;
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visibleHeight = 232;
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renderOffset = 0;
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@ -562,48 +566,19 @@ namespace BizHawk.Emulation.Computers.Commodore64
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spriteData = new byte[8, 64];
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// initialize screen buffer
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characterMemory = new byte[41];
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colorMemory = new byte[41];
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characterIndex = -1;
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charactersEnabled = false;
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characterMemory = new byte[40];
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colorMemory = new byte[40];
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// initialize registers
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HardReset();
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}
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private void GetBitmapData()
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{
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if (characterIndex < 0 || characterIndex >= 40)
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bitmapData = 0;
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else
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{
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int cMemIndex = characterMemory[characterIndex];
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if (regs.ECM)
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cMemIndex &= 0x3F;
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ushort offset = (ushort)((regs.CB << 11) + (cMemIndex * 8) + regs.RC);
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bitmapData = mem.VicRead(offset);
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}
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}
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private void GetScreenData(int index)
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{
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ushort offset = (ushort)((regs.VM << 10) + regs.VC);
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characterMemory[index] = mem.VicRead(offset);
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colorMemory[index] = mem.colorRam[regs.VC];
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}
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private void GetSpriteData(int index)
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{
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ushort offset = (ushort)((regs.VM << 10) + 0x3F8 + index);
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spritePointers[index] = (ushort)((regs.VM << 10) + (mem.VicRead(offset) * 64));
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for (ushort i = 0; i < 64; i++)
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spriteData[index, i] = mem.VicRead((ushort)(spritePointers[index] + i));
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}
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public void HardReset()
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{
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idle = true;
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refreshAddress = 0x3FFF;
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regs = new VicIIRegs();
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regs.RC = 7;
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signal.VicAEC = true;
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signal.VicIRQ = false;
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UpdateBorder();
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@ -611,20 +586,11 @@ namespace BizHawk.Emulation.Computers.Commodore64
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public void PerformCycle()
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{
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// reset VC and VCBASE if on scan 0
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if (regs.RASTER == 0x00)
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{
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regs.VCBASE = 0;
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regs.VC = 0;
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}
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// display enable check on line $30
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if (regs.RASTER == 0x30)
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{
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// display enable check on line 030 (this must be run every cycle)
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if (regs.RASTER == 0x030)
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displayEnabled = (displayEnabled | regs.DEN);
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}
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// badline calculation (for when the VIC must pause the CPU to get character data)
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// badline check
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if (regs.RASTER >= 0x030 && regs.RASTER < 0x0F8)
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badLine = ((regs.YSCROLL == (regs.RASTER & 0x07)) && displayEnabled);
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else
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@ -633,116 +599,74 @@ namespace BizHawk.Emulation.Computers.Commodore64
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if (badLine)
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idle = false;
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// decide what to do this cycle
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if (cycle == 0)
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// these actions are exclusive
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if ((regs.RASTER == 0x000 && cycle == 1) || (regs.RASTER > 0x000 && cycle == 0))
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{
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// if vblank, reset the raster position
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regs.RASTER++;
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if (regs.RASTER == rasterTotalLines)
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{
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rasterOffset = 0;
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regs.RASTER = 0;
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renderOffset = 0;
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displayEnabled = false;
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refreshAddress = 0x3FFF;
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}
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// check to see if we are within viewing area Y
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if (regs.RASTER == visibleBottom)
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visibleRenderY = false;
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if (regs.RASTER == visibleTop)
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visibleRenderY = true;
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// check for raster IRQ
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// IRQ is processed on cycle 1 of line 0 and cycle 0 on all other lines
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if (regs.RASTER == rasterInterruptLine)
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regs.IRST = true;
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}
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else if (cycle >= 1 && cycle < 10)
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{
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// fetch sprite data 3-7
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int index = (cycle >> 1) + 3;
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if (regs.MxE[index])
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{
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signal.VicAEC = false;
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if ((cycle & 0x01) == 0x00)
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{
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GetSpriteData(index);
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}
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}
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else
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{
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signal.VicAEC = true;
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}
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}
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else if (cycle >= 10 && cycle < 15)
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{
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// dram refresh
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mem.VicRead((ushort)refreshAddress);
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refreshAddress = (refreshAddress - 1) & 0xFF;
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refreshAddress |= 0x3F00;
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// VIC internal register reset on cycle 13
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if (cycle == 13)
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{
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regs.VC = regs.VCBASE;
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regs.VMLI = 0;
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characterIndex = -4;
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characterColumn = 0;
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if (badLine)
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{
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regs.RC = 0;
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}
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}
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}
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else if (cycle >= 15 && cycle < 55)
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{
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// screen memory c-access
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if (badLine)
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{
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// fetch video data
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signal.VicAEC = false;
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GetScreenData(cycle - 15);
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}
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else
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{
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signal.VicAEC = true;
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}
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regs.VC++;
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regs.VMLI++;
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PerformCycleScreenFetch();
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}
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else if (cycle == 55)
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{
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//signal.VicAEC = true;
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}
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else if (cycle == 57)
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{
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// increment VIC row counter
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if (regs.RC == 7)
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{
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idle = true;
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regs.VCBASE = regs.VC;
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}
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else
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{
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if (!idle)
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regs.RC = (regs.RC + 1) & 0x07;
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}
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}
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else if (cycle >= spriteFetchCycle)
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{
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// fetch sprite data 0-2
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int index = (cycle - spriteFetchCycle) >> 1;
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if (regs.MxE[index])
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{
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signal.VicAEC = false;
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if ((cycle & 0x01) == 0x00)
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{
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GetSpriteData(index);
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}
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}
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else
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{
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signal.VicAEC = true;
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}
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}
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else
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{
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// idle
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}
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// these actions can fall within the other ranges
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if (cycle == 13)
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{
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regs.VC = regs.VCBASE;
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regs.VMLI = 0;
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characterColumn = 0;
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if (badLine)
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{
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regs.RC = 0;
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}
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bitmapData = 0;
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colorData = 0;
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characterData = 0;
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}
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else if (cycle == spriteFetchStartCycle)
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{
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spriteFetchIndex = 0;
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}
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// sprite fetch
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if (spriteFetchIndex < 8)
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{
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PerformCycleSpriteFetch(spriteFetchIndex, spriteFetchCycle);
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spriteFetchCycle++;
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if (spriteFetchCycle >= 2)
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{
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spriteFetchCycle = 0;
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spriteFetchIndex++;
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}
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}
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// border check
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if (cycle == 63)
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{
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if ((regs.RASTER == borderTop) && (regs.DEN))
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@ -751,6 +675,75 @@ namespace BizHawk.Emulation.Computers.Commodore64
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borderOnVertical = true;
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}
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PerformCycleRender();
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// increment cycle
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cycle++;
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if (cycle == totalCycles)
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{
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cycle = 0;
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PerformCycleAdvanceRaster();
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}
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UpdateInterrupts();
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signal.VicIRQ = regs.IRQ;
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}
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private void PerformCycleAdvanceRaster()
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{
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regs.RASTER++;
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// if we reach the bottom, reset to the top
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if (regs.RASTER == rasterTotalLines)
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{
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regs.RASTER = 0;
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regs.VCBASE = 0;
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displayEnabled = false;
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}
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// check to see if we are within viewing area Y
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if (regs.RASTER == visibleBottom)
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{
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visibleRenderY = false;
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renderOffset = 0;
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}
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if (regs.RASTER == visibleTop)
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visibleRenderY = true;
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}
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private void PerformCycleGraphicFetch()
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{
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if (idle)
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{
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if (regs.ECM)
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mem.VicRead(0x39FF);
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else
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mem.VicRead(0x3FFF);
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}
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else
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{
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characterIndex = regs.VMLI - 1;
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if (characterIndex < 0 || characterIndex >= 40)
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{
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bitmapData = 0;
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colorData = 0;
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characterData = 0;
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}
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else
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{
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characterData = characterMemory[characterIndex];
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if (regs.ECM)
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characterData &= 0x3F;
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bitmapData = mem.VicRead((ushort)((regs.CB << 11) + (characterData * 8) + regs.RC));
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colorData = colorMemory[characterIndex];
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}
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regs.VC++;
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regs.VMLI++;
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}
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}
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private void PerformCycleRender()
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{
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// determine the plot mode
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if (!regs.ECM && !regs.BMM && !regs.MCM)
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Plotter = Plot000;
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@ -771,21 +764,14 @@ namespace BizHawk.Emulation.Computers.Commodore64
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for (int i = 0; i < 8; i++)
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{
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if ((rasterOffsetX & 0x07) == regs.XSCROLL)
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// draw screen memory if needed
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if (!idle && cycle >= 15 && cycle < 55)
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{
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characterColumn = 0;
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characterIndex++;
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GetBitmapData();
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}
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// pixel clock is 8x the VIC clock
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int pixel;
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// process raster position
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if (rasterOffsetX >= rasterWidth)
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{
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// reset to the left side
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rasterOffsetX -= rasterWidth;
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if ((rasterOffsetX & 0x07) == regs.XSCROLL)
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{
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characterColumn = 0;
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PerformCycleGraphicFetch();
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}
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}
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// check to see if we are within viewing area X
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@ -797,7 +783,6 @@ namespace BizHawk.Emulation.Computers.Commodore64
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// check to see if we are at the border
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if (rasterOffsetX == borderRight)
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borderOnMain = true;
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if (rasterOffsetX == borderLeft)
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{
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if (regs.RASTER == borderBottom)
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@ -808,46 +793,38 @@ namespace BizHawk.Emulation.Computers.Commodore64
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borderOnMain = false;
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}
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// draw the border if it is on, otherwise draw the screen
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if (borderOnMain || borderOnVertical)
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{
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pixel = regs.EC;
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}
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else
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{
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if (characterIndex >= 0 && characterIndex < 40)
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pixel = Plotter();
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else
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pixel = regs.BxC[0];
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}
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// plot the pixel if within visible range
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// render pixel
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if (visibleRenderX && visibleRenderY)
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{
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/*
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if (regs.RC == 0x00)
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pixel ^= 0x08;
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if ((regs.RASTER & 0x07) == regs.YSCROLL)
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pixel ^= 0x01;*/
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WritePixel(pixel);
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if (borderOnMain || borderOnVertical)
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WritePixel(regs.EC);
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else
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WritePixel(Plotter());
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}
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// increment raster position
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characterColumn++;
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rasterOffset++;
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rasterOffsetX++;
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characterColumn++;
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if (rasterOffsetX == rasterWidth)
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{
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rasterOffsetX -= rasterWidth;
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}
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}
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UpdateInterrupts();
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}
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signal.VicIRQ = regs.IRQ;
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private void PerformCycleScreenFetch()
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{
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ushort offset = (ushort)((regs.VM << 10) + regs.VC);
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characterMemory[regs.VMLI] = mem.VicRead(offset);
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colorMemory[regs.VMLI] = mem.colorRam[regs.VC];
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}
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cycle++;
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if (cycle == totalCycles)
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cycle = 0;
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hBlank = !visibleRenderX;
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vBlank = !visibleRenderY;
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private void PerformCycleSpriteFetch(int index, int fetchCycle)
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{
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ushort offset = (ushort)((regs.VM << 10) + 0x3F8 + index);
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spritePointers[index] = (ushort)((regs.VM << 10) + (mem.VicRead(offset) * 64));
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for (ushort i = 0; i < 64; i++)
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spriteData[index, i] = mem.VicRead((ushort)(spritePointers[index] + i));
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}
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// standard text mode
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@ -858,7 +835,7 @@ namespace BizHawk.Emulation.Computers.Commodore64
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byte charData = bitmapData;
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charData <<= characterColumn;
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if ((charData & 0x80) != 0x00)
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return colorMemory[characterIndex];
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return colorData;
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}
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return regs.BxC[0];
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}
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@ -868,7 +845,7 @@ namespace BizHawk.Emulation.Computers.Commodore64
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{
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if (characterColumn >= 0)
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{
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if ((colorMemory[characterIndex] & 0x08) != 0x00)
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if ((colorData & 0x08) != 0x00)
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{
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int offset = characterColumn;
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byte charData = bitmapData;
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@ -883,7 +860,7 @@ namespace BizHawk.Emulation.Computers.Commodore64
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case 2:
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return regs.BxC[charData];
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default:
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return colorMemory[characterIndex] & 0x07;
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return colorData & 0x07;
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}
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}
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else
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@ -914,9 +891,9 @@ namespace BizHawk.Emulation.Computers.Commodore64
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byte charData = bitmapData;
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charData <<= characterColumn;
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if ((charData & 0x80) != 0x00)
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return colorMemory[characterIndex];
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return colorData;
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else
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return regs.BxC[characterMemory[characterIndex] >> 6];
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return regs.BxC[characterData >> 6];
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}
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return regs.BxC[0];
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}
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