Intial commit

README.md

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+# 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.