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Added Snapshot save feature

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Marc Parsons
2026-04-28 11:24:50 +01:00
parent 851dfba78f
commit 38bef38f96
7 changed files with 103 additions and 31 deletions
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63
Desktop/Form1.cs
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@@ -237,6 +237,69 @@ namespace Desktop
});
}
private void SaveSNAMenuItem_Click(object? sender, EventArgs e)
{
_isPaused = true;
using (SaveFileDialog sfd = new SaveFileDialog())
{
sfd.Filter = "Spectrum SNA Files|*.sna";
if (sfd.ShowDialog() == DialogResult.OK)
{
SaveSNA(sfd.FileName);
}
}
_isPaused = false;
}
public void SaveSNA(string filepath)
{
// 0. Back up the live state BEFORE modifying it
ushort originalSP = _cpu.SP;
byte originalMemLow = _memoryBus.Read((ushort)(_cpu.SP - 2));
byte originalMemHigh = _memoryBus.Read((ushort)(_cpu.SP - 1));
// 1. We must push the PC onto the stack before saving!
_cpu.SP -= 2;
_memoryBus.Write(_cpu.SP, (byte)(_cpu.PC & 0xFF)); // Low byte
_memoryBus.Write((ushort)(_cpu.SP + 1), (byte)(_cpu.PC >> 8)); // High byte
using (FileStream fs = new FileStream(filepath, FileMode.Create))
using (BinaryWriter bw = new BinaryWriter(fs))
{
// 2. Write the 27-byte Header
bw.Write(_cpu.I);
bw.Write(_cpu.HL_Prime.Low); bw.Write(_cpu.HL_Prime.High);
bw.Write(_cpu.DE_Prime.Low); bw.Write(_cpu.DE_Prime.High);
bw.Write(_cpu.BC_Prime.Low); bw.Write(_cpu.BC_Prime.High);
bw.Write(_cpu.AF_Prime.Low); bw.Write(_cpu.AF_Prime.High);
bw.Write(_cpu.HL.Low); bw.Write(_cpu.HL.High);
bw.Write(_cpu.DE.Low); bw.Write(_cpu.DE.High);
bw.Write(_cpu.BC.Low); bw.Write(_cpu.BC.High);
bw.Write(_cpu.IY.Low); bw.Write(_cpu.IY.High);
bw.Write(_cpu.IX.Low); bw.Write(_cpu.IX.High);
// IFF2 determines the interrupt state in SNA
bw.Write((byte)(_cpu.IFF2 ? 0x04 : 0x00));
bw.Write(_cpu.R);
bw.Write(_cpu.AF.Low); bw.Write(_cpu.AF.High);
bw.Write((byte)(_cpu.SP & 0xFF)); bw.Write((byte)(_cpu.SP >> 8));
bw.Write((byte)_cpu.InterruptMode);
bw.Write(_simpleIoBus.BorderColorIndex);
// 3. Dump the 48K RAM
for (int i = 0x4000; i <= 0xFFFF; i++)
{
bw.Write(_memoryBus.Read((ushort)i));
}
}
// 4. RESTORE the emulator's state so the game can resume safely
_cpu.SP = originalSP;
_memoryBus.Write((ushort)(originalSP - 2), originalMemLow);
_memoryBus.Write((ushort)(originalSP - 1), originalMemHigh);
}
private void PopulateIncludedTapsMenu()
{
// 1. Get the current assembly (your .exe)