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More keys. Implemented Border. Completes LOAD readiness sequence

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This commit is contained in:
Marc Parsons
2026-04-18 01:55:08 +01:00
parent 389df3780e
commit 47f3a76bb2
5 changed files with 188 additions and 34 deletions
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86
Core/Cpu/Z80.cs
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@@ -1009,6 +1009,17 @@ namespace Core.Cpu
if ((AF.Low & 0x01) != 0) PC = addr;
return 10;
}
case 0xDB: // IN A, (n)
// 1. Fetch the immediate port offset byte
byte portOffsetDB = FetchByte();
// 2. The Z80 puts 'A' on the top 8 bits, and 'n' on the bottom 8 bits
ushort portAddressDB = (ushort)((AF.High << 8) | portOffsetDB);
// 3. Read from the I/O bus and store the result straight into the Accumulator
AF.High = _simpleIoBus.ReadPort(portAddressDB);
return 11;
case 0xE2: // JP PO, nn (Parity Odd / No Overflow)
{
ushort addr = FetchWord();
@@ -1251,7 +1262,7 @@ namespace Core.Cpu
throw new NotImplementedException($"Opcode 0x{opcode:X2} at PC 0x{(PC - 1):X4} is not implemented.");
}
}
private int ExecuteExtendedPrefix()
private int ExecuteExtendedPrefix() //ED
{
// Fetch the actual extended instruction
byte extendedOpcode = _memory.Read(PC++);
@@ -1376,6 +1387,9 @@ namespace Core.Cpu
AF.Low = newFlags;
return 12;
case 0x79: // OUT (C), A
_simpleIoBus.WritePort(BC.Word, AF.High);
return 12; // 12 T-States
case 0x7B: // LD SP, (nn)
// 1. Fetch the absolute 16-bit memory address from the instruction stream
byte addrLow = FetchByte();
@@ -1596,6 +1610,65 @@ namespace Core.Cpu
IX.Word = (ushort)((high << 8) | low);
return 14;
case 0x36: // LD (IX+d), n
// 1. Fetch the displacement byte first
sbyte offset36 = (sbyte)FetchByte();
// 2. Fetch the immediate 8-bit value second
byte n36 = FetchByte();
// 3. Calculate the exact memory address (IX + offset)
ushort address36 = (ushort)(IX.Word + offset36);
// 4. Write the immediate value directly into memory
_memory.Write(address36, n36);
return 19;
case 0x74: // LD (IX+d), H
// 1. Fetch the displacement byte and cast it to a signed sbyte
sbyte offset74 = (sbyte)FetchByte();
// 2. Calculate the exact memory address (IX + offset)
ushort address74 = (ushort)(IX.Word + offset74);
// 3. Write the contents of the L register (Low byte of HL) into memory
_memory.Write(address74, HL.High);
return 19;
case 0x75: // LD (IX+d), L
// 1. Fetch the displacement byte and cast it to a signed sbyte
sbyte offset75 = (sbyte)FetchByte();
// 2. Calculate the exact memory address (IX + offset)
ushort address75 = (ushort)(IX.Word + offset75);
// 3. Write the contents of the L register (Low byte of HL) into memory
_memory.Write(address75, HL.Low);
return 19;
case 0xE1: // POP IX
// 1. Read the low byte from the top of the stack
byte popLow = _memory.Read(SP);
SP++; // Move stack pointer up
// 2. Read the high byte
byte popHigh = _memory.Read(SP);
SP++; // Move stack pointer up again
// 3. Combine them and store in IX
IX.Word = (ushort)((popHigh << 8) | popLow);
return 14;
case 0xE5: // PUSH IX
// 1. Decrement the stack pointer and write the HIGH byte
SP--;
_memory.Write(SP, IX.High);
// 2. Decrement the stack pointer again and write the LOW byte
SP--;
_memory.Write(SP, IX.Low);
return 15;
case 0xE9: // JP (IX)
PC = IX.Word;
return 8;
@@ -1727,6 +1800,17 @@ namespace Core.Cpu
_memory.Write(targetAddress, BC.Low);
return 19; // Takes 19 T-States
}
case 0x72: // LD (IY+d), D
// 1. Fetch the displacement byte and cast it to a signed sbyte
sbyte offset72 = (sbyte)FetchByte();
// 2. Calculate the exact memory address (IY + offset)
ushort address72 = (ushort)(IY.Word + offset72);
// 3. Write the contents of the D register (High byte of DE) into memory
_memory.Write(address72, DE.High);
return 19; // 19 T-States
case 0x74: // LD (IY+d), H
// 1. Fetch the displacement byte and cast it to a signed sbyte
sbyte offset74 = (sbyte)FetchByte();

18
Core/Io/IO_Bus.cs
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@@ -5,8 +5,10 @@ namespace Core.Io
{
public class IO_Bus
{
// 8 rows representing the Spectrum keyboard matrix. Default to 0xFF (unpressed).
public byte[] KeyboardRows = new byte[8] { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
public byte BorderColorIndex { get; private set; } = 7; // 7 is White
// 8 rows representing the Spectrum keyboard matrix. Default to 0xFF (unpressed).
public byte[] KeyboardRows = new byte[8] { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
public byte ReadPort(ushort portAddress)
{
@@ -35,9 +37,17 @@ namespace Core.Io
return 0xFF;
}
public void WritePort(ushort portAddress, byte portValue)
public void WritePort(ushort portAddress, byte portValue)
{
// The ULA intercepts any write to an even port address
if ((portAddress & 0x01) == 0)
{
// The bottom 3 bits (0-2) define the border color!
BorderColorIndex = (byte)(portValue & 0x07);
// (Bits 3 and 4 handle the cassette MIC output and the internal speaker,
// which we will need when we start playing audio!)
}
}
}
}
}

45
Desktop/DebuggerForm.cs
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@@ -822,6 +822,11 @@ namespace Desktop
case 0xD8:
mnemonic = "RET C";
break;
case 0xDB: // IN A, (n)
n = _memoryBus.Read((ushort)(currentPc + 1));
mnemonic = $"IN A, (0x{n:X2})";
instructionLength = 2;
break;
case 0xDD:
{
byte ddOpcode = _memoryBus.Read((ushort)(currentPc + 1));
@@ -836,6 +841,39 @@ namespace Desktop
mnemonic = $"LD IX, 0x{ixVal:X4}";
instructionLength = 4;
}
else if (ddOpcode == 0x36) // LD (IX+d), n
{
sbyte d = (sbyte)_memoryBus.Read((ushort)(currentPc + 2));
n = _memoryBus.Read((ushort)(currentPc + 3));
string sign = d >= 0 ? "+" : "";
mnemonic = $"LD (IX{sign}{d}), 0x{n:X2}";
instructionLength = 4;
}
else if (ddOpcode == 0x74) // LD (IX+d), H
{
sbyte d = (sbyte)_memoryBus.Read((ushort)(currentPc + 2));
string sign = d >= 0 ? "+" : "";
mnemonic = $"LD (IX{sign}{d}), H";
instructionLength = 3;
}
else if (ddOpcode == 0x75) // LD (IX+d), L
{
sbyte d = (sbyte)_memoryBus.Read((ushort)(currentPc + 2));
string sign = d >= 0 ? "+" : "";
mnemonic = $"LD (IX{sign}{d}), L";
instructionLength = 3;
}
else if (ddOpcode == 0xE1) // POP IX
{
mnemonic = "POP IX";
instructionLength = 2;
}
else if (ddOpcode == 0xE5) // PUSH IX
{
mnemonic = "PUSH IX";
instructionLength = 2;
}
else if (ddOpcode == 0xE9) // JP (IX)
{
mnemonic = "JP (IX)";
@@ -1037,6 +1075,13 @@ namespace Desktop
mnemonic = $"LD L, (IY{signL}{offsetL})";
instructionLength = 3;
}
else if (fdOpcode == 0x72) // LD (IY+d), D
{
sbyte d = (sbyte)_memoryBus.Read((ushort)(currentPc + 2));
string sign = d >= 0 ? "+" : "";
mnemonic = $"LD (IY{sign}{d}), D";
instructionLength = 3;
}
else if (fdOpcode == 0x74) // LD (IY+d), H
{
sbyte d = (sbyte)_memoryBus.Read((ushort)(currentPc + 2));

11
Desktop/Form1.Designer.cs generated
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@@ -34,21 +34,24 @@
//
// picScreen
//
picScreen.Anchor = AnchorStyles.Top | AnchorStyles.Bottom | AnchorStyles.Left | AnchorStyles.Right;
picScreen.BackColor = Color.Black;
picScreen.Location = new Point(12, 12);
picScreen.Location = new Point(13, 13);
picScreen.Margin = new Padding(4);
picScreen.Name = "picScreen";
picScreen.Size = new Size(768, 576);
picScreen.Size = new Size(960, 768);
picScreen.SizeMode = PictureBoxSizeMode.Zoom;
picScreen.TabIndex = 0;
picScreen.TabStop = false;
//
// Form1
//
AutoScaleDimensions = new SizeF(8F, 20F);
AutoScaleDimensions = new SizeF(10F, 25F);
AutoScaleMode = AutoScaleMode.Font;
ClientSize = new Size(791, 596);
ClientSize = new Size(987, 791);
Controls.Add(picScreen);
KeyPreview = true;
Margin = new Padding(4);
Name = "Form1";
Text = "Parsons Sinclair ZX Spectrum 48K - 2026";
((System.ComponentModel.ISupportInitialize)picScreen).EndInit();

60
Desktop/Form1.cs
View File

@@ -73,10 +73,19 @@ namespace Desktop
public void RenderScreen()
{
_ulaFrameCount++;
// The Spectrum flashes every 16 frames.
// This boolean flips between true and false every 16 frames.
bool invertFlashPhase = (_ulaFrameCount % 32) >= 16;
int[] pixelData = new int[256 * 192];
// --- NEW: Expanded screen size (32px border on all sides) ---
const int screenWidth = 320;
const int screenHeight = 256;
const int borderSize = 32;
int[] pixelData = new int[screenWidth * screenHeight];
// --- NEW: Fill the background with the Border Color ---
// (Note: The hardware border always uses standard brightness, never bright)
int currentBorderColor = SpectrumColors[_simpleIoBus.BorderColorIndex];
Array.Fill(pixelData, currentBorderColor);
// Loop through the 6144 bytes of Pixel RAM
for (int offset = 0; offset < 6144; offset++)
@@ -84,14 +93,12 @@ namespace Desktop
ushort address = (ushort)(0x4000 + offset);
byte pixels = _memoryBus.Read(address);
// Unwind the Sinclair interlace
int y = ((offset & 0x0700) >> 8) |
((offset & 0x00E0) >> 2) |
((offset & 0x1800) >> 5);
int x = (offset & 0x001F) * 8;
// Fetch Color Attributes
int attrRow = y / 8;
int attrCol = x / 8;
ushort attrAddress = (ushort)(0x5800 + (attrRow * 32) + attrCol);
@@ -101,12 +108,12 @@ namespace Desktop
int paper = (attr >> 3) & 0x07;
int brightOffset = (attr & 0x40) != 0 ? 8 : 0;
bool isFlashSet = (attr & 0x80) != 0;
int inkColor = SpectrumColors[ink + brightOffset];
int paperColor = SpectrumColors[paper + brightOffset];
if (isFlashSet && invertFlashPhase)
{
// Swap the ink and paper colors for this character block!
int temp = inkColor;
inkColor = paperColor;
paperColor = temp;
@@ -116,14 +123,20 @@ namespace Desktop
for (int bit = 0; bit < 8; bit++)
{
bool isPixelSet = (pixels & (1 << (7 - bit))) != 0;
pixelData[(y * 256) + (x + bit)] = isPixelSet ? inkColor : paperColor;
// --- NEW: Add the 32px border offset to our X and Y calculations! ---
int renderY = y + borderSize;
int renderX = x + borderSize + bit;
// Map it to our new, wider pixel array
pixelData[(renderY * screenWidth) + renderX] = isPixelSet ? inkColor : paperColor;
}
}
// Blast it to the PictureBox
Bitmap bmp = new Bitmap(256, 192, PixelFormat.Format32bppArgb);
// --- NEW: Update Bitmap dimensions to match the new 320x256 array ---
Bitmap bmp = new Bitmap(screenWidth, screenHeight, PixelFormat.Format32bppArgb);
BitmapData bmpData = bmp.LockBits(
new Rectangle(0, 0, 256, 192),
new Rectangle(0, 0, screenWidth, screenHeight),
ImageLockMode.WriteOnly,
bmp.PixelFormat);
@@ -133,8 +146,6 @@ namespace Desktop
if (picScreen.Image != null) picScreen.Image.Dispose();
picScreen.Image = bmp;
}
// Helper method to update the IO Bus state
private void UpdateMatrix(int row, int col, bool isPressed)
{
if (isPressed)
@@ -167,6 +178,16 @@ namespace Desktop
{
switch (key)
{
// Row 1: A, S, D, F, G
case Keys.A: UpdateMatrix(1, 0, isPressed); break;
case Keys.S: UpdateMatrix(1, 1, isPressed); break;
case Keys.D: UpdateMatrix(1, 2, isPressed); break;
case Keys.F: UpdateMatrix(1, 3, isPressed); break;
case Keys.G: UpdateMatrix(1, 4, isPressed); break;
// Row 5:
case Keys.P: UpdateMatrix(5, 0, isPressed); break;
// Row 6: ENTER, L, K, J, H
case Keys.Enter: UpdateMatrix(6, 0, isPressed); break;
case Keys.L: UpdateMatrix(6, 1, isPressed); break;
@@ -179,21 +200,12 @@ namespace Desktop
case Keys.M: UpdateMatrix(7, 2, isPressed); break;
case Keys.N: UpdateMatrix(7, 3, isPressed); break;
case Keys.B: UpdateMatrix(7, 4, isPressed); break;
case Keys.ControlKey: UpdateMatrix(7, 1, isPressed); break; // Symbol Shift
// Row 1: A, S, D, F, G
case Keys.A: UpdateMatrix(1, 0, isPressed); break;
case Keys.S: UpdateMatrix(1, 1, isPressed); break;
case Keys.D: UpdateMatrix(1, 2, isPressed); break;
case Keys.F: UpdateMatrix(1, 3, isPressed); break;
case Keys.G: UpdateMatrix(1, 4, isPressed); break;
// Map the rest of the alphabet and numbers here as you need them!
}
}
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
}
}
}