Front end

The menus: the top-level mode 0 of Game_Frame 0x4d0780. They use 917 functions (0x4cf000-0x510000, 248 KB of code), most of them page callbacks. The port is in src/fe/.

The process

Mode 0 runs one process: group 0x817da0, state table 0x523bc8, transitions 0x523c18. Each transition is (state, kind, event, next). The states are:

State	Update	Draw	What
0	0x4d15e0	none	The start-up. The first time (0x516120 set) it does the full loading (event 1). Back from a game it reloads (event 0, or 6 for the demo).
1	0x4d1b40	0x4d1080	The title and copyright textures, for 5 s
2	0x4d1b40	0x4d1370	The Bink logo and credit line, for 5 s
3, 4	0x4d1ba0, 0x4d1c30	none	The cm.bik and Intro.bik movies
5	0x4d1a90	0x4d0ea0	The title, until select or 5 s; then the menu music starts
6	0x4d1c90	0x4d0a80	The menus: Menu_Input on the current page, and the page's draw
7	0x4d1cc0	0x4d0ba0	A rally's movie, before the first stage of a championship or single rally
8	0x4d1e10	none	Three pauses of 5 s
9	0x4d1e90	none	Out of the front end, to mode 2 (the stage set-up) or mode 3 (the race)

Event 0 from state 6 goes to state 7, and event 2 goes to state 9. The start page's frame callback (0x4ef590) calls 0x4d2070, which posts event 0 with the way out recorded: on to the game, or for the demo, to the set-up or to the race.

The start-up

The first run of 0x4d15e0:

1. The territory comes from the registry's Sku_Type. The CD's is Europe, which gives five languages.
2. The options' defaults (0x510410) and the input devices.
3. The archives (0x4d2380): FrontEnd\Common.bfl, FrontEnd\Res640.bfl, CountrySpecific\<region>\FERes640E.bfl and each language's text archive.
4. The textures: title, copyright, Bink, arrows, dot matrices, banners, flags, medals and the cars' blueprints (0x4e2e50, 0x4d2590).
5. The five menu sounds from Sounds\menu. Four fonts: hel_12pt, hel_15pt, hel_36pt and dot. The 533 strings of f<language>.txt. The credits.
6. Every page (Pages_Build 0x4e9f70).
7. The stage maps (0x4d5ca0): <rally><nn>.dmd from Common.bfl.

Paths are built from the formats in the exe and the directories of Paths_Init 0x40e8d0 (src/game/paths.c).

The menu engine

The engine is at 0x49ff50-0x4a0c50 (src/fe/menu.c). A page is a 0x1e0-byte record in the BSS:

Offset	Field
+0x00	A title string, or NULL
+0x04	The title's text number
+0x06	The item count
+0x07	The selection
+0x08	The parent page
+0x0c	The first selection for Menu_Reset, -1 none
+0x0d	1: the items run up and down. 0: they run across.
+0x0e	Flags: 1 the selection moves, 2 values change, 4 select works, 8 back works, 0x10 wrap, 0x40 no parent
+0x0f	The last move's direction
+0x10	The value shared by type 6 items
+0x14	22 items of 0x14 bytes each
+0x1cc	enter
+0x1d0	frame
+0x1d4	draw
+0x1d8	leave
+0x1dc	The hooks

An item has these fields: a label pointer, the text number (+4), flags (+6: 1 enabled, 2 selectable, 4 wraps, 8 select steps the value), the type (+7), an id (+8), the value count and the value (+0xa, +0xb), the target page (+0xc) and a function (+0x10). The types are 1 back, 2 page, 3 list, 4 action and 6 shared list.

The input bits are those of the input record in the menus' key mode (0x49f480): 1 left, 2 right, 4 up, 8 down, 0x10 Enter, 0x20 Escape. A page whose items run across moves its selection with left and right and changes values with up and down; one whose items run up and down does the opposite. A pending page change runs the old page's leave callback and the new page's enter callback (with "back" set when the move goes back), and plays the set's sounds.

The pages

There are 94 constructors (0x4f5520-0x4fa780). Each one calls the builders (0x49ffd0, 0x4a00a0-0x4a02e0, 0x4a0430). The port's src/fe/pages.c was translated from them, then checked call by call against the push sequences in the disassembly. The way to a stage:

Page	What
0x8221d8	The language, first run only; a waving flag in dots (0x4d28c0)
0x81d6d8	The main menu: drivers, rally, arcade, network, options, credits, quit
0x823a38	Mode select: championship, single rally, single stage, time trial, challenge
0x823fd8	Difficulty (Expert locked until unlocked, 0x52b03c)
0x81f2f8	Number of players, drawn as dot figures
0x8241b8	Driver select: load a profile, create one, or play as a guest
0x824a38	Tag entry: three letters, typed or picked from the letter grid
0x821e18	Car select: the profile's open cars, with front and back blueprints, livery, power and handling bars
0x81cf58	Transmission
0x81eb78	Country select, with the rallies open (0x4f02e0)
0x81e3f8	Stage select: the map, location, length, surfaces and records
0x81f4d8	Weather (single stage): random, or the rally's weathers
0x8214b8	The start

Most pages share two drawings:

• The item strip (0x4d2cd0 and the main menu's 0x4d45b0): the items in a row near the bottom of the screen, the selected one at x = 102 of 640. A new selection slides into place over 250 ms. The slide is kept in twelve scroller records (0x819140, 0x78 bytes apart).
• The column list (0x4d3360): arrowed rows between separator lines.

Leaving

State 9 does the following before it sets mode 2 or 3:

1. It sets up the championship's tables (0x4cf060) and the options' mode byte (0x4eabc0).
2. It chooses the rally's weather (0x40dc30, src/game/weather.c): each stage's start and end weather, from the rally's three tables of ten types; the light levels; the rain.
3. It copies each car's set-up from the rally's table (0x406820).
4. It writes the selection into the mode word.
5. It frees the front end's memory and textures.

In the port

The port differs from the original in these places:

• The Bink movies are skipped.
• The music streams as the original (8 segments of 0xfe80 bytes), decoded by the port's MS ADPCM decoder in place of the ACM.
• Nothing is saved: the game info, the profiles, the leaderboards and the controller configuration.
• Mode 2 (World_Frame 0x4ff450, the set-up and service screens) is not ported. The race starts straight away through src/game/play.c, and returns to the menus after the stage.
• 206 page callbacks are still logged stubs (src/fe/stubs.c): mostly the options, the profiles, the championship, the arcade and the network pages.

The race's menus

The race uses the same menu engine for two more sets of pages.

The pause menu is at 0x401000-0x405500 (src/game/pause.c). Its pages are built at the race's start (0x403500):

• 0x52ad60, the main page: graphics, sound, controller, restart, exit and continue. The controller row is passed over: 0x402bf0 moves the selection off it.
• 0x52a670: the music, effects and co-driver volumes.
• 0x529af8 and 0x52a0c0: the restart and exit confirmations.
• The graphics, camera and display pages.

Escape (key binding 10, bit 0x400 of the race's input) pauses the game on the line, in the countdown and on the stage. While paused the race is not updated, but the fades still run. Restart and exit start a fade on every car. At its end the fade posts the race's event 1, which goes to the results state, and sets a flag: 0x53810c for a restart, 0x53810d for an exit. The results state (0x41e8d0) then either puts the cars back on the line (0x41e6b0, then event 4) or leaves for the front end.

The stage's results are at 0x448e00-0x454400 (src/game/results.c). They are drawn over the replay (0x44b330 in state 10's draw). Their input runs in each step of state 10 (0x448e70). They are started by state 9 once every player has finished (0x44a1b0). For one player on a single stage the pages are:

1. The replay's title and the driver (0x44b7b0).
2. The stage time page (0x44bcd0): each split's time and the total, beside the stage record's.
3. "Congratulations" (0x44d790), only when the time beat the record. 0x4cfa10 writes the new record.
4. The standings board against the computer drivers (0x44d960).
5. The choices (0x44af70, 0x453c50): restart, restart at the service area, quit. Each fades out and posts the race's event 1, as the pause menu does.

The computer drivers' times come from the stage's .tm file for the difficulty (Stage_LoadTm 0x455300, src/game/opponents.c). The file holds sixteen drivers, each with a base, a random range and dry and wet adjustments, and each split's dry and wet times. From these, 0x455470-0x456960 work out:

• each driver's rating, whose order is the final standings;
• each driver's split times, shaken within the difficulty's limits.

The players' times go in at their splits (0x455590). The weather's change along the stage is not ported, so the model takes the stage as dry throughout. The other modes' result pages are not ported yet.