file goonies.rom
size 32,768 bytes
sha256 2ba602b1a17e4797da1588afe6e65640331c15746bf5959f4778b404be929dde
catalogue RC-734
machine MSX1A 32 KB cartridge in pages 1 and 2, 0x4000..0xBFFF. No paging, no mapper: all 32 KB are there at once and the Z80 sees the lot.
The first is the usual one: at 0x4000 sit the "AB" signature and the address of INIT, which here is 0x406A. STATEMENT, DEVICE and TEXT are zero, and so are the six reserved bytes.
The second, at 0x4010, is not an MSX thing: it is the Konami Game Master header, for the house's cheat cartridge that plugs into the other slot. It starts with "CD", then 07 34 — the 0x07 of the RC-7xx range and the 0x34 of RC-734 — and then eleven bytes with the variables the Game Master wants to touch.
This cartridge never reads it: tools/quien_lee.py gives zero references to 0x4010..0x401E. It is there for the cartridge next door to read.
Eight of the Konami games here carry it, and all eight are disassembled in this series: Konami's Soccer and Football (RC-732), this one, Konami's Boxing (RC-736), Yie Ar Kung-Fu II (RC-737), Knightmare (RC-739), Twin Bee (RC-740), Nemesis (RC-742) and F-1 Spirit (RC-752). The marker in front goes by year, not by catalogue number: AB on the 1985 ones and CD from 1986 on.
At the end of the cartridge, behind the 0xFF padding, sit the title in katakana written backwards and the catalogue number:
グーニーズ 34 0xAAIt is read with the house code: index = byte − 0x80, and indices 0 to 44 are the gojūon in order. The finding is Manuel Pazos's, who uncovered it in 2021; without him nobody would know to look there.
This cartridge also pins down a character that was still unconfirmed: 0xBA, index 58, is the long-vowel mark ー. グーニーズ only works out that way.
0x470F pushes eight bytes into registers 0 to 7, one at a time:
| reg | value | what it says |
|---|---|---|
| R0 | 0x02 | mode 2 (SCREEN 2) |
| R1 | 0xE2 | 16 KB, display on, interrupt enabled, 16x16 sprites |
| R2 | 0x0E | names at 0x3800 |
| R3 | 0x7F | colour: base 0x0000, mask 0x1FFF |
| R4 | 0x07 | patterns: base 0x2000, mask 0x1FFF |
| R5 | 0x76 | sprite attributes at 0x3B00 |
| R6 | 0x03 | sprite patterns at 0x1800 |
| R7 | 0xE4 | dark blue border |
Careful with R3 and R4: in mode 2 they are not an address, they are base and mask. Reading them as an address gives you correct shapes with banded colours, which is the classic symptom.
The geometry that comes out of it is upside down from the usual:
colour 0x0000..0x17FF three 0x800 banks
sprite patterns 0x1800..0x1FFF 64 patterns
patterns 0x2000..0x37FF three 0x800 banks
names 0x3800..0x3AFF 768 tiles
sprite attributes 0x3B00..0x3B7F 32 spritesThe colour table sits below the pattern table. An ld hl,00008h in this cartridge does not point at patterns: it points at colour.
| bytes | % | |
|---|---|---|
| traced code | 17,422 | 53.17 |
| identified data | 15,346 | 46.83 |
| unexplained | 0 | 0.00 |
| total | 32,768 | 100.00 |
Counted by tools/presupuesto.py, and checked by make sanity on every build.
The table dispatcher — pop hl / add a,a / call ... / ld e,(hl) / inc hl / ld d,(hl) / ex de,hl / jp (hl) — is the same in eleven of the house's cartridges. Searching for its tail (5e 23 56 eb e9) across the 47 ROMs to hand turns it up exactly once in each: Sky Jaguar (RC-721), Yie Ar Kung-Fu (both builds), Hyper Rally (RC-718), Road Fighter (RC-730), Konami's Ping Pong (RC-731), Konami's Soccer and Football (RC-732), Hyper Sports 3 (RC-733), this one (RC-734), Nemesis (RC-742) and F-1 Spirit (RC-752).
In this cartridge it is used twenty-six times, and all twenty-six tables sit immediately behind their call.