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SLUS_008.84: what is where

Star Wars Episode I: The Phantom Menace, PlayStation, USA Rev 1 (SLUS_008.84, sha1 02f73ad2115f2fbb5bd1880615db0f9ac7b5055c, 487 424 bytes). The original USA release (8dda79b3…) is a different link of the same game: the two executables differ in about 400 000 bytes, so Rev 1 is the only target for now.

Developer: Big Ape Productions, for LucasArts, 1999. The internal codename is Zanzibar: paths are c:\zanzibar\data\..., and the disc's padding file is ZANZIBAR.000. The engine's subsystems are called Taskman, Bapworld, Bapview, Bapsound and Bappush ("BAP" = Big Ape Productions).

Executable image

vram file what
0x80010000 0x800 .text: game code (C), 823 functions (src/game*.c)
0x80057734 ... 0x8005D970 hand-written asm modules with data inside .text (raw pieces: D_80057734, D_8005B678, D_8005C168)
0x8005E210 0x4EA10 __start (PSY-Q startup: clears gp..0x801FF000, heap = 0x800CBCBC, jumps to main 0x800236D8)
0x8006044C 0x50C4C PSY-Q libraries (first signature-matched object; see below)
0x80071590 0x61D90 game .rodata / .data (file table at 0x800715A0, stream table at 0x80071FA8)
0x800838E4 0x740E4 second .text: hand-written GTE / ordering-table routines (asm/us/gte_asm.s)
0x8008585C 0x7605C library .rdata / .data
0x8008630C 0x76B0C gp; .sbss (zeros, still in the file image up to 0x80086800)
0x80086800 .bss to 0x800CBCBC; the heap follows

The game is compiled -G0: no $gp-relative data in C code (5 uses, all in hand-written asm).

Compiler

PSY-Q 4.3's CCPSX: GCC 2.8.1 + ASPSX 2.79 (emulated by maspsx). Evidence: the library objects are PSY-Q 4.3 (libgpu sys.c 1.140, 1998/01/12), and GCC 2.8.1 reproduces the game's code shape (explicit %hi/%lo pairs into the destination register) where 2.7.2 does not (lui $at macro expansions). No function is fully matched yet; func_80010000 is one instruction off (register allocation of a loop bound), which is a source-shape question.

No GCC 2.x vtables (8-byte {delta, index, pfn} entries) were found in the data, and the code-pointer arrays look like switch tables: the PSX port is probably C, although the PC game is C++.

PSY-Q libraries

tools/psyq_match.py with lab313ru's signatures finds ~105 objects, mostly 4.3 with libpad (4.5/4.7), some libcd/libds objects from 4.7 and DSCB.OBJ from 4.0: the game links a mix. Matched: libapi, libc, libetc (VSync, intr_dma, intr_vb), libgte (InitGeom, RotTransPers, ratan2, ...), libgpu (AddPrim, GetClut, SetDrawTPage), libspu (most of it), libds (DsReadySystem, DsControl, ...), libpad, libmcrd, libcard.

Not matched as whole objects (they are there, judging by their strings): libgpu SYS.OBJ (ResetGraph, DrawSync, ClearOTag...), libcd (CD_sync, DiskError), libetc INTR.OBJ. Per-function signatures would place them.

Disc

file sectors what
FILE.000 23.. all game data, addressed by name through the file table (tools/tpm_files.py)
FILE.001 17225.. streamed audio (stream table)
FILE.002 64868.. streamed data, starts with a header naming BigCity01SkyDock
FILE.003 164678.. movies (MDEC STR: 0x80010160 sector headers)
SLUS_008.84 272563 the executable
ZANZIBAR.000 272802.. 28 MB of zeros (padding to the outer edge)

The file table (0x800715A0, 107 entries)

struct FileEntry { u8 msf[3]; u8 pad; u32 size; char name[16]; };

msf is BCD minute:second:frame inside FILE.000, with the 2 s lead-in (00:02:00 = first sector). Contents: 17 .PCV (sound banks), 11 .LVL (levels), 13 .VRM + 12 .VRJ (VRAM images), 11 .MAP, 44 .RGB (load screens), TPAGE1.BTP, TITLE.VRM, FRONT.VRM, FMV.CPE.

At boot File_Init (0x80011BF8) turns the four archives' compiled-in disc sectors (g_DiscFileSectors: 23, 17225, 64868, 164678) into positions and rebases every table to absolute ones. The game never reads the ISO9660 directory at run time: a port only has to serve absolute sector reads.

table at entries archive
g_FileTable 0x800715A0 107 x 24 B FILE.000
g_StreamTable 0x80071FA8 2624 x 8 B FILE.001
g_StreamTable002 0x800771A8 168 x 8 B FILE.002
g_MovieTable 0x800776E8 12 x 8 B FILE.003

main (0x800236D8): __main, hardware/library init (InitGeom among it), File_Init, display setup func_8001164C(320, 240, 1, 1), three 0x1B800-byte buffers from 0x800BBCE4 into D_80088A1C[3], then func_80023CB0 and func_800237BC (the game loop, presumably).

The stream table (0x80071FA8)

struct StreamEntry { u8 msf[3]; u8 pad; u32 length; };

2624 streams (voice / music / effect cues) in FILE.001, positions relative to the archive.

Data formats (first look)

  • .RGB 245 760 bytes = 320x256, 24-bit RGB (load screens, title logos; displayed in the GPU's 24-bit mode).
  • .LVL starts with a table of section sizes/offsets; contains .baf names (models + animation sets per character: queen.baf, r2d2.baf, ...).
  • .PCV sound bank: u32 size, u32 count, then 16-byte SPU voice attribute records (7f40 xx00 ...), then ADPCM.
  • .VRM / .VRJ: VRAM uploads (.VRJ looks like 15-bit pixel data; .VRM carries a record list first).
  • FMV.CPE: code (an overlay, the movie player; starts with a MIPS prologue). It will need its own splat segment once its load address is known.

The PC version

The PSX game is a port of the PC game (WMAIN.EXE), whose engine OpenPhantom (https://github.com/OpenPhantom/OpenPhantom) has been patching: legacy/src/common/engine_types.h documents structures from the PC engine (actors, camera, sound) that the PSX code should share in spirit, if not in layout. Item / weapon / level / message strings match the PC game's.