Hyper Sports 3, Konami, 1985. Catalogue number RC-733. 32 KB of ROM in an MSX1 cartridge, no mapper, no SCC and no RAM of its own.
0x4000 .. 0xBFFF the cartridge's 32 KB, pages 1 and 2
0xE000 .. 0xE7FF the 2 KB of work RAM, and it uses no moreThe header is the sixteen bytes at 0x4000: the AB signature, the INIT address (0x405A) and everything else at zero —STATEMENT, DEVICE, TEXT and the six reserved bytes—.
The loop at 0x4488 writes them in order, 0 to 7, taking each value from a table. For the game they are:
02 E2 0E 7F 07 76 03 E4
R2 = 0x0E -> name table 0x3800
R3 = 0x7F -> colour base 0x0000, mask 0x3FF
R4 = 0x07 -> patterns base 0x2000
R5 = 0x76 -> sprite attrs 0x3B00
R6 = 0x03 -> sprite patterns 0x1800In SCREEN 2 R3 and R4 are not an address, they are a base and a mask. With these values the screen is split into the usual three thirds, each with its own 256 patterns and 256 rows of colour. Which is why the cartridge has a routine (L_4405) that decompresses the same block into all three at once, skipping 0x0800 each time.
Of the 2 KB of work RAM, twelve bytes are the only ones that do not start at zero. INIT copies them from 0x40CF to 0xE053, and they are the world records for the four events, in BCD. They sit in RAM rather than ROM because the game overwrites them as soon as they are beaten.
The whole game is one counter and eleven tables, and all eleven sit glued right behind their call L_4050:
pop hl / add a,a / call L_4046 / ld e,(hl) / inc hl / ld d,(hl)
ex de,hl / jp (hl)The pop hl recovers its own return address, which is the start of the table. It is the dispatcher shared across this family of Konami cartridges.
The entry count of each table is not estimated: it is fixed by the constraint that no entry can point inside the table itself. All eleven are in src/hypersports3.entries with their arithmetic down to the byte. The longest is the one at 0xA934, with thirteen entries; the topmost is 0x4109, with nine, which dispatches the logo, the title, the events and the ending.
The whole player lives between 0x4AD2 and 0x4DA2, with its data right behind. The door is L_4ADD: you pass it the sound number in A. The track table ends exactly at its own lowest entry, 0x4E1C, which is what fixes its length without having to guess.
The period table has twelve values, not ten, and the last two are hidden inside the pointer table that follows. All twelve land within one unit of the exact semitone: it is a chromatic octave.
The last sixteen bytes —0xBFF0 to 0xBFFF— carry the game's title in katakana, backwards: ハイパースポーツ3, its length (0x0D), the 0x33 of RC-733 and an 0xAA to close. Nothing reads it: not one instruction in the cartridge points there.
The mark was discovered by Manuel Pazos, and it is in many of Konami's cartridges from these years.
There are none. No initials, no names, no build dates anywhere in the 32 KB. The only thing that signs is the hidden mark, and it signs for the company, not for the people.