# H8/536 ROM Decompiler

This repo now includes a standalone Python helper for the H8/536 ROM image:

```powershell
python h8536_decompiler.py ROM\M27C512@DIP28_1.BIN --out build\rom_decompiled.asm --json build\rom_decompiled.json
```

On this machine the Windows `python.exe` entry is a Microsoft Store launcher stub, so validation was run with WSL:

```powershell
ubuntu.exe run python3 h8536_decompiler.py --out build/rom_decompiled.asm --json build/rom_decompiled.json
```

## What It Does

- Decodes the H8/500 instruction set used by the H8/536.
- Reads the H8/536 minimum-mode vector table from the ROM.
- Recursively traces reachable code from reset, interrupt, and trap vectors.
- Emits labels for branch and call targets.
- Annotates H8/536 on-chip register accesses such as `P1DDR`, `SYSCR1`, `WCR`, and timer/SCI/A-D registers.
- Handles the E-clock transfer instructions `MOVFPE` and `MOVTPE`.

The generated listing is written to:

```text
build/rom_decompiled.asm
```

The optional JSON output is useful for scripts or later analysis:

```text
build/rom_decompiled.json
```

## Useful Options

```powershell
python h8536_decompiler.py --help
```

- `--mode min|max`: vector format. This ROM appears to be minimum mode; `min` is the default.
- `--entry H'1234`: add an extra entry point to recursive tracing.
- `--linear`: linear-sweep the selected range instead of tracing from vectors.
- `--start H'1000 --end H'D100`: constrain the decode range.
- `--br H'FE`: resolve short absolute `@aa:8` operands through a known base-register value.

## Code Layout

- `h8536_decompiler.py`: compatibility wrapper for the CLI.
- `h8536/cli.py`: argument parsing and end-to-end orchestration.
- `h8536/decoder.py`: instruction and effective-address decoding.
- `h8536/tables.py`: manual-derived opcode/vector/register tables.
- `h8536/vectors.py`: exception vector parsing.
- `h8536/analysis.py`: recursive tracing, linear sweep, and labels.
- `h8536/render.py`: assembly and JSON output.
- `h8536/model.py`, `h8536/rom.py`, `h8536/formatting.py`: shared data structures and helpers.