Wikifang:Telefang 1 Translation Patch/State Machine

Telefang's primary game loop is structured as a state machine. Each iteration of the game loop executes a handful of predefined tasks, and then indexes a jump table to load other screens' code. This indexing can be recursive, with individual states running their own predefined tasks before jumping into sub-states. This is known to recurse to at least fourth-order state machines.

State machines are indexed through four primary SystemState variables, and two secondary state variables. The secondary state variables are used in certain states for various reasons - usually to prevent overwriting the state of another screen. (Why they didn't set up a proper state stack for this sort of thing is beyond me...)

WRAM Addr	Disassembly Symbol
$C3E0	W_SystemState	First order state index
$C3E1	W_SystemSubState	Second order state index
$C3E2	W_SystemSubSubState	Third order state index (primary)
$C3E3	(Not named)	Fourth order state index (presumed primary, not yet seen in practice)
$1:D400	W_Battle_SubSubState	Third order state index (secondary)
$1:D401	W_Battle_4thOrderSubState	Fourth order state index (secondary)

System State Machine

Here's a breakdown of the sixteen first-order states in Telefang.

State ID.	Impl. ROM Addr	Disassembly Symbol
$00	$02:5300		Intro logos.
$01	$02:493F		Title screen
$02	$02:4000
$03	$04:4000	TitleMenu_GameStateMachine	Title menu (continue/new game/options/link)
$04	$02:40BF		Attract screen
$05	$0B:1EA1		Overworld
$06	$1C:4000	Encounter_GameStateMachine	Random, T-Fanger, and other plot-important encounters
$07	$05:441B		Battle system
$08	$1D:4000	Victory_ExternalStateMachine	Victory processing screens at end of battle (level-up, contact loss, game over)
$09	$2:4B8B		Status screen (used in a lot of places...)
$0A	$2:4824
$0B	Aliases state $0C
$0C	$4:45C0		Pause menu (contacts/index/save/dial etc)
$0D	$2:44CF
$0E	$2:458E
$0F	$1F:4000		Link communications (vs battle/trade/melo-d)

Title Menu

State ID.	Impl. ROM Addr	Disassembly Symbol
$03 00			Load CGB Palette 0
$03 01			Initialize phone graphics & sprites
$03 02			Load initial menu tilemaps & initialize menu state
$03 03			Load tilemaps for each individual menu option.
$03 04			Load color palettes for the menu. Then, move the window and background layers in place for the upcoming animation.
$03 05			Final commit of palettes. On DMG, this state configures the legacy palette registers instead.
$03 06
$03 07			Animate the two halves of the phone scrolling in.
$03 08			Player input handling
$03 09			Start menu-scrolling-up animation.
$03 0A			Menu-scrolling-up animation, frame 2.
$03 0B			End menu-scrolling animation (either direction).
$03 0C			Start menu-scrolling-down animation.
$03 0D			Menu-scrolling-down animation, frame 2.
$03 0E			Fade out screen, then transfer to overworld ($05 00)
$03 0F
$03 10
$03 11			Time input
$03 12
$03 13			Initialize naming input, clear string buffers.
$03 14			Name input
$03 15			Saves the input buffer to the player name buffer.
$03 16
$03 17
$03 18			(Called when you select "Sound" on the menu. More info required.)
$03 19
$03 1A
$03 1B
$03 1C			Save-file overwrite warning
$03 1D
$03 1E
$03 1F	Aliases state $03 01
$03 20			Denjuu nicknaming screen init
$03 21			Denjuu nicknaming palette fade-in
$03 22			Denjuu nicknaming input handler
$03 23			Denjuu nickname save
$03 24
$03 25