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More OpCodes - working towards ZEXALL perfection

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This commit is contained in:
Marc Parsons
2026-04-22 22:38:53 +01:00
parent b50f7a79da
commit 02680cb92d
6 changed files with 364 additions and 38 deletions
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58
Core/Io/IO_Bus.cs
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@@ -5,37 +5,47 @@ using static System.Runtime.InteropServices.JavaScript.JSType;
namespace Core.Io
{
public class IO_Bus
{
{
public byte BorderColorIndex { get; private set; } = 7;
public bool BeeperState { get; private set; } = false;
public byte[] KeyboardRows = new byte[8] { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
TapManager _tapManager = new TapManager();
public byte ReadPort(ushort portAddress)
{
// The Spectrum ULA responds to any even port address (where the lowest bit is 0)
if ((portAddress & 0x01) == 0)
public IO_Bus(TapManager tapManager)
{
byte highByte = (byte)(portAddress >> 8); // The B register!
byte result = 0xFF; // Start assuming no keys are pressed
// The ROM pulls a specific bit low (0) in the high byte to request a row.
// Sometimes it pulls multiple bits low to scan multiple rows at once, so we AND the results.
if ((highByte & 0x01) == 0) result &= KeyboardRows[0]; // 0xFE: CAPS, Z, X, C, V
if ((highByte & 0x02) == 0) result &= KeyboardRows[1]; // 0xFD: A, S, D, F, G
if ((highByte & 0x04) == 0) result &= KeyboardRows[2]; // 0xFB: Q, W, E, R, T
if ((highByte & 0x08) == 0) result &= KeyboardRows[3]; // 0xF7: 1, 2, 3, 4, 5
if ((highByte & 0x10) == 0) result &= KeyboardRows[4]; // 0xEF: 0, 9, 8, 7, 6
if ((highByte & 0x20) == 0) result &= KeyboardRows[5]; // 0xDF: P, O, I, U, Y
if ((highByte & 0x40) == 0) result &= KeyboardRows[6]; // 0xBF: ENTER, L, K, J, H
if ((highByte & 0x80) == 0) result &= KeyboardRows[7]; // 0x7F: SPACE, SYM, M, N, B
// The top 3 bits (5, 6, 7) are unused by the keyboard and usually return 1 on a real Spectrum
return (byte)(result | 0xE0);
_tapManager = tapManager;
}
// Return 0xFF for unhandled ports
return 0xFF;
}
public byte ReadPort(ushort portAddress)
{
// The Spectrum ULA responds to any even port address (where the lowest bit is 0)
if ((portAddress & 0x01) == 0)
{
byte highByte = (byte)(portAddress >> 8); // The B register!
byte result = 0xFF; // Start assuming no keys are pressed
// The ROM pulls a specific bit low (0) in the high byte to request a row.
// Sometimes it pulls multiple bits low to scan multiple rows at once, so we AND the results.
if ((highByte & 0x01) == 0) result &= KeyboardRows[0]; // 0xFE: CAPS, Z, X, C, V
if ((highByte & 0x02) == 0) result &= KeyboardRows[1]; // 0xFD: A, S, D, F, G
if ((highByte & 0x04) == 0) result &= KeyboardRows[2]; // 0xFB: Q, W, E, R, T
if ((highByte & 0x08) == 0) result &= KeyboardRows[3]; // 0xF7: 1, 2, 3, 4, 5
if ((highByte & 0x10) == 0) result &= KeyboardRows[4]; // 0xEF: 0, 9, 8, 7, 6
if ((highByte & 0x20) == 0) result &= KeyboardRows[5]; // 0xDF: P, O, I, U, Y
if ((highByte & 0x40) == 0) result &= KeyboardRows[6]; // 0xBF: ENTER, L, K, J, H
if ((highByte & 0x80) == 0) result &= KeyboardRows[7]; // 0x7F: SPACE, SYM, M, N, B
if (_tapManager.EarBit) result |= 0x40; // Set Bit 6 high
else result &= 0xBF; // Set Bit 6 low
//return result;
// The top 3 bits (5, 6, 7) are unused by the keyboard and usually return 1 on a real Spectrum
return (byte)(result | 0xE0);
}
// Return 0xFF for unhandled ports
return 0xFF;
}
public void WritePort(ushort portAddress, byte portValue)
{