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Pissed about trying to fix a number of bugs

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This commit is contained in:
Marc Parsons
2026-05-12 01:34:05 +01:00
parent 95ac0ec7c1
commit edb41bdb3a
8 changed files with 75 additions and 20 deletions
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1
Core/Cpu/Z80.cs
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@@ -190,6 +190,7 @@ namespace Core.Cpu
// Fetch the next opcode and increment the Program Counter
byte opcode = ReadMemory(PC++);
R = (byte)((R + 1) & 0x7F);
int tStates = ExecuteOpcode(opcode);
TotalTStates += tStates;

37
Core/Video/SmsVdp.cs
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@@ -18,9 +18,12 @@ namespace Core.Video
private int _tStateCounter = 0;
private int _currentScanline = 0;
private int _lineCounter = 0;
private byte _statusRegister = 0x00;
public bool InterruptPending => (_statusRegister & 0x80) != 0 && (Registers[1] & 0x20) != 0;
public bool InterruptPending =>
((_statusRegister & 0x80) != 0 && (Registers[1] & 0x20) != 0) || // VBlank
((_statusRegister & 0x40) != 0 && (Registers[0] & 0x10) != 0); // Line Interrupt
public byte ReadDataPort() // Port 0xBE
{
@@ -110,6 +113,20 @@ namespace Core.Video
if (_tStateCounter >= 228)
{
_tStateCounter -= 228;
//// --- LINE INTERRUPT LOGIC ---
//if (_currentScanline <= 192)
//{
// _lineCounter--;
// if (_lineCounter < 0)
// {
// _lineCounter = Registers[10]; // Reload counter
// _statusRegister |= 0x40; // Set Line Interrupt Flag (Bit 6)
// }
//}
//else
//{
// _lineCounter = Registers[10]; // Reload outside active display
//}
_currentScanline++;
// Line 192 is the exact moment the screen finishes drawing!
@@ -117,8 +134,16 @@ namespace Core.Video
{
_statusRegister |= 0x80; // Set Bit 7 (VBlank Flag) to 1
RenderBackground(); // <--- DRAW THE FRAME!
RenderSprites();
if ((Registers[1] & 0x40) != 0)
{
RenderBackground();
RenderSprites();
}
else
{
// Screen is off! Fill it with black (or the background color)
Array.Fill(FrameBuffer, unchecked((int)0xFF000000));
}
}
// End of the NTSC frame (262 lines)
@@ -220,6 +245,7 @@ namespace Core.Video
// 3. Register 1 determines sprite size (8x8 or 8x16)
bool is8x16 = (Registers[1] & 0x02) != 0;
bool shiftSpritesLeft = (Registers[0] & 0x08) != 0;
// The SMS can draw a maximum of 64 sprites
for (int i = 0; i < 64; i++)
@@ -261,6 +287,11 @@ namespace Core.Video
for (int px = 0; px < 8; px++)
{
int screenX = x + px;
// THE FIX: Shift the pixel left if commanded!
if (shiftSpritesLeft) screenX -= 8;
// If it shifted off the left edge, skip it!
if (screenX < 0 || screenX >= 256) continue;
// If this pixel is off the right side of the screen, skip it
if (screenX >= 256) continue;