Path: blob/master/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Vic.cs
2 views
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
{
public sealed partial class Vic
{
/*
Commodore VIC-II 6567/6569/6572 core.
Many thanks to:
- Christian Bauer for the VIC-II document.
http://www.zimmers.net/cbmpics/cbm/c64/vic-ii.txt
- VICE team for the addendum to the above document.
http://vice-emu.sourceforge.net/plain/VIC-Addendum.txt
- Whoever scanned the CSG 6567 preliminary datasheet.
http://www.classiccmp.org/cini/pdf/Commodore/ds_6567.pdf
- Michael Huth for die shots of the 6569R3 chip (to get ideas how to implement)
http://mail.lipsia.de/~enigma/neu/6581.html
*/
public Func<int, int> ReadColorRam;
public Func<int, int> ReadMemory;
public bool ReadAec() { return _pinAec; }
public bool ReadBa() { return _pinBa; }
public bool ReadIrq() { return _pinIrq; }
[SaveState.DoNotSave] private readonly int _cyclesPerSec;
[SaveState.DoNotSave] private readonly int[] _rasterXPipeline;
[SaveState.DoNotSave] private readonly int[] _fetchPipeline;
[SaveState.DoNotSave] private readonly int[] _baPipeline;
[SaveState.DoNotSave] private readonly int[] _actPipeline;
[SaveState.DoNotSave] private readonly int _totalCycles;
[SaveState.DoNotSave] private readonly int _totalLines;
private int _cyclesExecuted;
[SaveState.DoNotSave] private int _hblankStartCheckXRaster;
[SaveState.DoNotSave] private int _hblankEndCheckXRaster;
[SaveState.DoNotSave] private int _pixelRatioNum;
[SaveState.DoNotSave] private int _pixelRatioDen;
public Vic(int newCycles, int newLines, IList<int[]> newPipeline, int newCyclesPerSec, int hblankStart, int hblankEnd, int vblankStart, int vblankEnd, C64.BorderType borderType, int pixelRatioNum, int pixelRatioDen)
{
Debug.WriteLine("C64 VIC timings:");
Debug.WriteLine("RX FTCH BA ACT");
for (var i = 0; i < newPipeline[0].Length; i++)
{
Debug.WriteLine("{0:x4} {1:x4} {2:x4} {3:x8}", newPipeline[0][i], newPipeline[1][i], newPipeline[2][i], newPipeline[3][i]);
}
_pixelRatioNum = pixelRatioNum;
_pixelRatioDen = pixelRatioDen;
_rasterXPipeline = newPipeline[0];
_fetchPipeline = newPipeline[1];
_baPipeline = newPipeline[2];
_actPipeline = newPipeline[3];
_totalCycles = newCycles;
_totalLines = newLines;
_cyclesPerSec = newCyclesPerSec;
ConfigureBlanking(newLines, hblankStart, hblankEnd, vblankStart, vblankEnd, borderType);
_sprites = new Sprite[8];
for (var i = 0; i < 8; i++)
_sprites[i] = new Sprite();
_sprite0 = _sprites[0];
_sprite1 = _sprites[1];
_sprite2 = _sprites[2];
_sprite3 = _sprites[3];
_sprite4 = _sprites[4];
_sprite5 = _sprites[5];
_sprite6 = _sprites[6];
_sprite7 = _sprites[7];
_bufferC = new int[40];
_bufferG = new int[40];
}
private void ConfigureBlanking(int lines, int hblankStart, int hblankEnd, int vblankStart, int vblankEnd,
C64.BorderType borderType)
{
var newHblankStart = hblankStart;
var newHblankEnd = hblankEnd;
var newVblankStart = vblankStart;
var newVblankEnd = vblankEnd;
var hBorderSize = 16; // must be a multiple of 4
var vBorderSize = hBorderSize*_pixelRatioNum/_pixelRatioDen; // to keep top and bottom in proportion
var maxWidth = _rasterXPipeline.Max();
switch (borderType)
{
case C64.BorderType.Full:
newHblankStart = -1;
newHblankEnd = -1;
_hblank = false;
newVblankStart = -1;
newVblankEnd = -1;
_vblank = false;
break;
case C64.BorderType.Normal:
newHblankStart = hblankStart;
newHblankEnd = hblankEnd;
newVblankStart = vblankStart;
newVblankEnd = vblankEnd;
_vblank = true;
_hblank = true;
break;
case C64.BorderType.SmallProportional:
_vblank = true;
_hblank = true;
newHblankStart = 0x158 + PixBufferSize + hBorderSize;
newHblankEnd = 0x018 + PixBufferSize - hBorderSize;
newVblankStart = 0xFA + vBorderSize;
newVblankEnd = 0x32 - vBorderSize;
break;
case C64.BorderType.SmallFixed:
_vblank = true;
_hblank = true;
newHblankStart = 0x158 + PixBufferSize + hBorderSize;
newHblankEnd = 0x018 + PixBufferSize - hBorderSize;
newVblankStart = 0xFA + hBorderSize;
newVblankEnd = 0x32 - hBorderSize;
break;
}
// wrap values
newHblankStart = WrapValue(0, maxWidth, newHblankStart);
newHblankEnd = WrapValue(0, maxWidth, newHblankEnd);
newVblankStart = WrapValue(0, lines, newVblankStart);
newVblankEnd = WrapValue(0, lines, newVblankEnd);
// calculate output dimensions
_hblankStartCheckXRaster = newHblankStart & 0xFFC;
_hblankEndCheckXRaster = newHblankEnd & 0xFFC;
_vblankStart = newVblankStart;
_vblankEnd = newVblankEnd;
_bufWidth = TimingBuilder_ScreenWidth(_rasterXPipeline, newHblankStart, newHblankEnd);
_bufHeight = TimingBuilder_ScreenHeight(newVblankStart, newVblankEnd, lines);
_buf = new int[_bufWidth * _bufHeight];
_bufLength = _buf.Length;
VirtualWidth = _bufWidth*_pixelRatioNum/_pixelRatioDen;
VirtualHeight = _bufHeight;
}
private int WrapValue(int min, int max, int val)
{
if (min == max)
{
return min;
}
var width = Math.Abs(min - max);
while (val > max)
{
val -= width;
}
while (val < min)
{
val += width;
}
return val;
}
public int CyclesPerFrame
{
get
{
return _totalCycles * _totalLines;
}
}
public int CyclesPerSecond
{
get
{
return _cyclesPerSec;
}
}
public void ExecutePhase()
{
// phi1
// advance cycle and optionally raster line
_cycle++;
if (_cycle > _totalCycles)
{
// border check
if (_rasterLine == _borderB)
_borderOnVertical = true;
if (_rasterLine == _borderT && _displayEnable)
_borderOnVertical = false;
// vblank check
if (_rasterLine == _vblankStart)
_vblank = true;
if (_rasterLine == _vblankEnd)
_vblank = false;
// reset to beginning of rasterline
_cycleIndex = 0;
_cycle = 1;
_rasterLine++;
if (_rasterLine == _totalLines)
{
// reset to rasterline 0
_rasterLine = 0;
_vcbase = 0;
_vc = 0;
_badlineEnable = false;
_refreshCounter = 0xFF;
_cyclesExecuted = 0;
}
}
// bg collision clear
if (_spriteBackgroundCollisionClearPending)
{
foreach (var spr in _sprites)
{
spr.CollideData = false;
}
_spriteBackgroundCollisionClearPending = false;
}
// sprite collision clear
if (_spriteSpriteCollisionClearPending)
{
foreach (var spr in _sprites)
{
spr.CollideSprite = false;
}
_spriteSpriteCollisionClearPending = false;
}
// phi2
// start of rasterline
if ((_cycle == RasterIrqLineXCycle && _rasterLine > 0) || (_cycle == RasterIrqLine0Cycle && _rasterLine == 0))
{
_rasterInterruptTriggered = false;
if (_rasterLine == LastDmaLine)
_badlineEnable = false;
}
// rasterline IRQ compare
if (_rasterLine != _rasterInterruptLine)
{
_rasterInterruptTriggered = false;
}
else
{
if (!_rasterInterruptTriggered)
{
_rasterInterruptTriggered = true;
_intRaster = true;
}
}
// check top and bottom border
if (_rasterLine == _borderB)
{
_borderOnVertical = true;
}
if (_displayEnable && _rasterLine == _borderT)
{
_borderOnVertical = false;
}
// display enable compare
if (_rasterLine == FirstDmaLine)
_badlineEnable |= _displayEnable;
// badline compare
if (_badlineEnable)
{
if ((_rasterLine & 0x7) == _yScroll)
{
_badline = true;
// go into display state on a badline
_idle = false;
}
else
{
_badline = false;
}
}
else
{
_badline = false;
}
// render
ParseCycle();
Render();
ParseCycle();
Render();
_extraColorModeBuffer = _extraColorMode;
// if the BA counter is nonzero, allow CPU bus access
if (_pinBa)
_baCount = BaResetCounter;
else if (_baCount > 0)
_baCount--;
_pinAec = _pinBa || _baCount > 0;
// must always come last
UpdatePins();
_cyclesExecuted++;
}
private void UpdateBorder()
{
_borderL = _columnSelect ? BorderLeft40 : BorderLeft38;
_borderR = _columnSelect ? BorderRight40 : BorderRight38;
_borderT = _rowSelect ? BorderTop25 : BorderTop24;
_borderB = _rowSelect ? BorderBottom25 : BorderBottom24;
}
private void UpdatePins()
{
var irqTemp = !(
(_enableIntRaster & _intRaster) |
(_enableIntSpriteDataCollision & _intSpriteDataCollision) |
(_enableIntSpriteCollision & _intSpriteCollision) |
(_enableIntLightPen & _intLightPen));
_pinIrq = irqTemp;
}
private void UpdateVideoMode()
{
if (!_extraColorMode && !_bitmapMode && !_multicolorMode)
{
_videoMode = VideoMode000;
return;
}
if (!_extraColorMode && !_bitmapMode && _multicolorMode)
{
_videoMode = VideoMode001;
return;
}
if (!_extraColorMode && _bitmapMode && !_multicolorMode)
{
_videoMode = VideoMode010;
return;
}
if (!_extraColorMode && _bitmapMode && _multicolorMode)
{
_videoMode = VideoMode011;
return;
}
if (_extraColorMode && !_bitmapMode && !_multicolorMode)
{
_videoMode = VideoMode100;
return;
}
_videoMode = VideoModeInvalid;
}
}
}