“Sonic The Hedgehog 2 (World) (Rev B)”

Cite as: “Sonic The Hedgehog 2 (World) (Rev B)”
Licence: proprietary; never redistributed (docs/data-policy.md#roms)
Credit: Sega
Notes: No-Intro "Sonic The Hedgehog 2 (World) (Rev B)": 1 MB, header serial GM 00001051-02. MAME's megadriv software list has the same SHA-1 as "sonic2c", "Sonic The Hedgehog 2 (World, rev. B, ripped from Sonic Compilation)". sonicretro-s2disasm's `gameRevision = 2` build is the disassembly's reconstruction of revision 2, not this ROM: they differ in 244,967 bytes. Sonic's object matches that build item for item apart from addresses and one jump table entry the build adds, and the collision routines it calls, CalcSine, CalcAngle, ObjectMove, ObjectMoveAndFall and ReadJoypads are its bytes (s2disasm/rom-matches-revision-2, probes/lab/sonic-2-revision.mjs), while RAM variables from about `$FFFFFF60` up sit at other addresses (Player_option `$FF7C`, Player_mode `$FF7A`, Two_player_mode `$FFB8`); the probes use this ROM's (probes/jump-physics/sonic-2-lib.lua).

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In the No-Intro Sonic The Hedgehog 2 (World) (Rev B) ROM, Sonic's object (`Obj01`) is the code s2disasm builds with `gameRevision = 2`, item for item, apart from absolute addresses, RAM variables at other addresses, branch displacements, and offset table entries, and less one jump table entry the build has after `Sonic_HurtStop`; the collision routines it calls (`AnglePos` up to `Obj79`), `CalcSine` and `CalcAngle` with their tables, `ObjectMoveAndFall`, `ObjectMove`, and `ReadJoypads` are that build's bytes. The build as a whole is not this ROM byte for byte.	`0x19EBE-0x1B8170x1E1C6-0x1F043`	Code