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

376 lines
9.8 KiB
C#

using System;
using System.Collections.Generic;
using System.Diagnostics;
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
- US Patent US4561659, inventors: James W. Redfield; Albert J. Charpentier
https://patents.google.com/patent/US4561659
*/
public Func<int, int> ReadColorRam;
public Func<int, int> ReadMemory;
public bool ReadAec() { return _pinAec; }
public bool ReadBa() { return _pinBa; }
public bool ReadIrq() { return (_irqBuffer & 1) == 0; }
private readonly int[] _rasterXPipeline;
private readonly int[] _fetchPipeline;
private readonly int[] _baPipeline;
private readonly int[] _actPipeline;
private readonly int _totalCycles;
private readonly int _totalLines;
private int _irqBuffer;
private int _hblankStartCheckXRaster;
private int _hblankEndCheckXRaster;
private readonly int _pixelRatioNum;
private readonly int _pixelRatioDen;
private readonly int _cyclesPerSecNum;
private readonly int _cyclesPerSecDen;
public Vic(int newCycles, int newLines, IList<int[]> newPipeline, int cyclesPerSecNum, int cyclesPerSecDen, 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;
_cyclesPerSecNum = cyclesPerSecNum;
_cyclesPerSecDen = cyclesPerSecDen;
ConfigureBlanking(newLines, hblankStart, hblankEnd, vblankStart, vblankEnd, borderType);
_sprites = new Sprite[8];
for (var i = 0; i < 8; i++)
_sprites[i] = new Sprite(i);
_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];
}
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 + hBorderSize;
newHblankEnd = 0x018 - hBorderSize;
newVblankStart = 0xFA + vBorderSize;
newVblankEnd = 0x32 - vBorderSize;
break;
case C64.BorderType.SmallFixed:
_vblank = true;
_hblank = true;
newHblankStart = 0x158 + hBorderSize;
newHblankEnd = 0x018 - hBorderSize;
newVblankStart = 0xFA + hBorderSize;
newVblankEnd = 0x32 - hBorderSize;
break;
case C64.BorderType.None:
newHblankStart = 0x158;
newHblankEnd = 0x018;
newVblankStart = 0xFA;
newVblankEnd = 0x32;
_vblank = true;
_hblank = true;
break;
}
// wrap values
if (_hblank)
{
newHblankStart = WrapValue(0, maxWidth, newHblankStart);
newHblankEnd = WrapValue(0, maxWidth, newHblankEnd);
}
if (_vblank)
{
newVblankStart = WrapValue(0, lines, newVblankStart);
newVblankEnd = WrapValue(0, lines, newVblankEnd);
}
// calculate output dimensions
_hblankStartCheckXRaster = newHblankStart & 0xFFC;
_hblankEndCheckXRaster = newHblankEnd & 0xFFC;
_vblankStart = newVblankStart;
_vblankEnd = newVblankEnd;
BufferWidth = TimingBuilder_ScreenWidth(_rasterXPipeline, newHblankStart, newHblankEnd);
BufferHeight = TimingBuilder_ScreenHeight(newVblankStart, newVblankEnd, lines);
_buf = new int[BufferWidth * BufferHeight];
_bufLength = _buf.Length;
VirtualWidth = BufferWidth * _pixelRatioNum / _pixelRatioDen;
VirtualHeight = BufferHeight;
}
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 => _totalCycles * _totalLines;
public void ExecutePhase1()
{
// phi1
_dataCPrev |= (_dataC & 0xFFF) << 12;
// advance cycle and optionally raster line
_cycle++;
if (_cycle > _totalCycles)
{
// 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;
_refreshCounter = 0xFF;
}
}
// 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;
}
// start of rasterline
if ((_cycle == RasterIrqLineXCycle && _rasterLine > 0) || (_cycle == RasterIrqLine0Cycle && _rasterLine == 0))
{
if (_rasterLine == BadLineDisableRaster)
_badlineEnable = false;
// raster compares are done here
if (_rasterLine == _rasterInterruptLine)
{
_intRaster = true;
}
}
// render
ParseCycle();
UpdateBa();
UpdatePins();
Render();
}
public void ExecutePhase2()
{
// phi2
_dataCPrev >>= 12;
// border check
if (_cycle == _totalCycles)
{
if (_rasterLine == _borderB)
_borderOnVertical = true;
else if (_rasterLine == _borderT - 1 && _displayEnable)
_borderOnVertical = false;
}
// display enable compare
if (_rasterLine == BadLineEnableRaster)
{
_badlineEnable |= _displayEnable;
}
// badline compare
_vcEnable = !_idle;
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();
UpdatePins();
Render();
}
private void UpdateBa()
{
if (_ba)
_baCount = BaResetCounter;
else if (_baCount >= 0)
_baCount--;
}
private void UpdateBorder()
{
_borderL = _columnSelect ? BorderLeft40 : BorderLeft38;
_borderR = _columnSelect ? BorderRight40 : BorderRight38;
_borderT = _rowSelect ? BorderTop25 : BorderTop24;
_borderB = _rowSelect ? BorderBottom25 : BorderBottom24;
}
private void UpdatePins()
{
// IRQ is treated as a delay line
var intIrq = (_enableIntRaster && _intRaster) ? 0x0002 : 0x0000;
var sdIrq = (_enableIntSpriteDataCollision & _intSpriteDataCollision) ? 0x0001 : 0x0000;
var ssIrq = (_enableIntSpriteCollision & _intSpriteCollision) ? 0x0001 : 0x0000;
var lpIrq = (_enableIntLightPen & _intLightPen) ? 0x0001 : 0x0000;
_irqBuffer >>= 1;
_irqBuffer |= intIrq | sdIrq | ssIrq | lpIrq;
_pinAec = _ba || _baCount >= 0;
_pinBa = _ba;
}
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;
}
}
}