NEX Snapshot

NEX is a snapshot format for the ZX Spectrum Next. In addition to the standard CPU registers and RAM banks, it supports Next-specific features including multiple screen types (Layer 2, ULA, LoRes, HiRes, HiColour), copper code, and a palette. NEX does not store shadow register data.

Details about the NEX format can be found at https://wiki.specnext.dev/NEX_file_format.

API

Class	Description
NexFormat	Singleton format for reading and writing NEX snapshots.
NexFile	Represents a NEX snapshot file.
NexHeader	512-byte header containing registers and hardware configuration.
NexBank	A 16 KB RAM bank.
NexScreen	An attached screen buffer.

Reading and Writing

// Read
using var stream = File.OpenRead("snapshot.nex");
NexFile nex = NexFormat.Instance.Read(stream);

// Write
using var output = File.Create("output.nex");
NexFormat.Instance.Write(nex, output);

Accessing State

// CPU registers
var regs = nex.Registers;
Console.WriteLine($"PC: 0x{regs.PC:X4}  SP: 0x{regs.SP:X4}");

// Header fields
Console.WriteLine($"Version: {nex.Header.VersionString}");
Console.WriteLine($"RAM Required: {nex.Header.RamRequired}");
Console.WriteLine($"Entry Bank: {nex.Header.EntryBank}");

// Banks
foreach (NexBank bank in nex.Banks)
    Console.WriteLine($"Bank {bank.BankNumber}: {bank.Data.Length} bytes");

// Screens
foreach (NexScreen screen in nex.Screens)
    Console.WriteLine($"Screen: {screen.Type}");