Getting started

The game · The tape · The code · Findings · Open questions

This repository holds a commented disassembly of War in Middle Earth for the MSX (Melbourne House / Dro Soft, 1989). Everything here comes out of the binary and can be generated from it again.

What you need

Python 3 (no third-party packages)
pasmo, to reassemble
z80dasm, used only for the mnemonics
the tape, which this repository does not distribute

The tape goes in the root, named war.tsx, and the Makefile asks for it by sha256:

13c636328d1714d5e00419141ca1a7ac9c7a3a04d7ec2b26545212aab1d81208

It is a TSX, not a .cas: the blocks are not MSX blocks but ZX Spectrum ones, because the conversion brought the whole tape system across. That is in The tape.

The test that matters

make verify

This reassembles the five listings with pasmo and compares each one, byte for byte, against the piece of tape it belongs to. If all five say OK: reproducible byte a byte, the disassembly has invented nothing.

Everything else you can run

make            # the whole cycle: extract, trace, list, verify
make listados   # regenerates the five src/war_*.asm
make sanity     # the checks reassembly does NOT cover
make test       # the tests
make imagenes   # redraws the PNGs in docs/imagenes from the tape
make web        # regenerates this site

make sanity is the one that watches for what a correct reassembly can hide: data being read as code, and tape bytes left unexplained. Today it says 62,261 out of 62,261, 100%.

The five listings

The game runs with all four pages in RAM and no BIOS, and the three big blocks are not run where they land: the boot code relocates them. That is why there are five listings and not three.

listing	org	what it is
`war_loader.asm`	`0xD6D8`	the loader: sets up RAM and reads the four blocks
`war_pantalla.asm`	`0x88B8`	the loading screen (almost all data)
`war_bajo.asm`	`0x0190`	the MSX layer: VRAM, keyboard, joystick, colour, tape
`war_medio.asm`	`0x5E00`	the game
`war_alto.asm`	`0x9E00`	graphics, map and tables (all data)

And a word about the pictures

None of the ones in docs/imagenes/ is a screenshot. tools/render_carga.py and tools/render_graficos.py draw them by reading the tape's bytes in the ranges the listing delimits. If a range were mislabelled, it would come out as noise.