Getting started

What is distributed here is a patch, parche/dunkshot_msx2.ips (292 bytes), never a cartridge image. You need your own dump of Dunk Shot (HAL Laboratory, 1986), the 32 KB cartridge with sha256 a1891e038566596a9f67067b8ea4694709aa9fee93c8ac0379360b30ea3abe62.

Applying it

With any IPS tool (Lunar IPS, Floating IPS, flips...), or with these lines of Python:

rom = bytearray(open("dunkshot.rom", "rb").read())
ips = open("parche/dunkshot_msx2.ips", "rb").read()
i = 5
while ips[i:i + 3] != b"EOF":
    a, n = int.from_bytes(ips[i:i + 3], "big"), int.from_bytes(ips[i + 3:i + 5], "big")
    rom[a:a + n] = ips[i + 5:i + 5 + n]
    i += 5 + n
open("dunkshot_msx2.rom", "wb").write(rom)

The result must have sha256 e5e14b0f7b188b77ae7b8daa28d98ee1e8c9bfc3d6479b9b93c0afbfd1037e6c. It is a plain 32 KB cartridge, no mapper. In openMSX:

openmsx -machine Philips_NMS_8250 -cart dunkshot_msx2.rom

Any MSX2 should do; on an MSX1 it plays as the original, flicker included.

Building it

You need Python 3, GNU make, Pasmo and your dump as dunkshot.rom at the root of the repository:

make            # the listing, reassembly, checks, the patch and the tests
make parche     # only the patch: work/dunkshot_msx2.rom and parche/dunkshot_msx2.ips
make web        # this website, in docs/

tools/parche_msx2.py assembles the new pieces with Pasmo, checks that every byte it overwrites is the one it expects, patches the operands and writes the patched ROM, the IPS and parche/parche_msx2.asm, the listing of the new code. tests/test_parche.py checks that the IPS gives back exactly that ROM and touches only the 24 stretches it declares.

What else is in the repository

This repository starts from the commented disassembly of Dunk Shot, with its history: src/dunkshot.asm is the listing that reassembles the original byte for byte, and every address on these pages can be looked up there. The tools of the disassembly are still here (make runs them); the ones of the patch are: