Global Variables and Constants

This page contains a listing of every global variable defined in the game, along with the declarations and a brief description of what each one does.

For our purposes, a global variable is anything that is defined outside of a function, whether it is declared static (private to its compilation unit) or not. This page also includes enums, #defines, and really anything else that seems useful to document.

Common Types

These are the enumerations and custom types that are frequently used. Generally any variable that holds an unsigned data type will use one of the following:

enum {false = 0, true};
typedef unsigned char byte;   /* 8-bit unsigned integer */
typedef unsigned int  word;   /* 16-bit unsigned integer */
typedef unsigned long dword;  /* 32-bit unsigned integer */
typedef word bool;            /* Boolean stored in a machine word (16-bit) */
typedef byte bbool;           /* Boolean stored in a byte */

`ACT_*`

#define ACT_BASKET_NULL         0
#define ACT_STAR_FLOAT          1
#define ACT_JUMP_PAD_FLOOR      2
#define ACT_ARROW_PISTON_W      3
#define ACT_ARROW_PISTON_E      4
#define ACT_FIREBALL_W          5
#define ACT_FIREBALL_E          6
#define ACT_HEAD_SWITCH_BLUE    7
#define ACT_HEAD_SWITCH_RED     8
#define ACT_HEAD_SWITCH_GREEN   9
#define ACT_HEAD_SWITCH_YELLOW  10
#define ACT_DOOR_BLUE           11
#define ACT_DOOR_RED            12
#define ACT_DOOR_GREEN          13
#define ACT_DOOR_YELLOW         14
#define ACT_JUMP_PAD_ROBOT      16
#define ACT_SPIKES_FLOOR        17
#define ACT_SPIKES_FLOOR_RECIP  18
#define ACT_SAW_BLADE_VERT      20
#define ACT_SAW_BLADE_HORIZ     22
#define ACT_BOMB_ARMED          24
#define ACT_CABBAGE             25
#define ACT_POWER_UP_FLOAT      28
#define ACT_BARREL_POWER_UP     29
#define ACT_BASKET_GRN_TOMATO   31
#define ACT_GRN_TOMATO          32
#define ACT_BASKET_RED_TOMATO   33
#define ACT_RED_TOMATO          34
#define ACT_BARREL_YEL_PEAR     35
#define ACT_YEL_PEAR            36
#define ACT_BARREL_ONION        37
#define ACT_ONION               38
#define ACT_EXIT_SIGN           39
#define ACT_SPEAR               40
#define ACT_SPEAR_RECIP         41
#define ACT_GRN_SLIME_THROB     42
#define ACT_GRN_SLIME_DRIP      43
#define ACT_FLYING_WISP         44
#define ACT_TWO_TONS_CRUSHER    45
#define ACT_JUMPING_BULLET      46
#define ACT_STONE_HEAD_CRUSHER  47
#define ACT_PYRAMID_CEIL        48
#define ACT_PYRAMID_FALLING     49
#define ACT_PYRAMID_FLOOR       50
#define ACT_GHOST               51
#define ACT_BASKET_GRN_GOURD    52
#define ACT_BASKET_BLU_SPHERES  53
#define ACT_MOON                54
#define ACT_HEART_PLANT         55
#define ACT_BARREL_BOMB         56
#define ACT_BOMB_IDLE           57
#define ACT_BARREL_JUMP_PAD_FL  58
#define ACT_SWITCH_PLATFORMS    59
#define ACT_SWITCH_MYSTERY_WALL 61
#define ACT_MYSTERY_WALL        62
#define ACT_SPIKES_FLOOR_BENT   63
#define ACT_MONUMENT            64
#define ACT_BABY_GHOST          65
#define ACT_PROJECTILE_SW       66
#define ACT_PROJECTILE_SE       67
#define ACT_PROJECTILE_S        68
#define ACT_ROAMER_SLUG         69
#define ACT_PIPE_CORNER_N       70
#define ACT_PIPE_CORNER_S       71
#define ACT_PIPE_CORNER_W       72
#define ACT_PIPE_CORNER_E       73
#define ACT_BABY_GHOST_EGG_PROX 74
#define ACT_BABY_GHOST_EGG      75
#define ACT_SHARP_ROBOT_FLOOR   78
#define ACT_SHARP_ROBOT_CEIL    80
#define ACT_BASKET_HAMBURGER    81
#define ACT_HAMBURGER           82
#define ACT_CLAM_PLANT_FLOOR    83
#define ACT_CLAM_PLANT_CEIL     84
#define ACT_GRAPES              85
#define ACT_PARACHUTE_BALL      86
#define ACT_SPIKES_E            87
#define ACT_SPIKES_E_RECIP      88
#define ACT_SPIKES_W            89
#define ACT_BEAM_ROBOT          90
#define ACT_SPLITTING_PLATFORM  91
#define ACT_SPARK               92
#define ACT_BASKET_DANCE_MUSH   93
#define ACT_DANCING_MUSHROOM    94
#define ACT_EYE_PLANT_FLOOR     95
#define ACT_EYE_PLANT_CEIL      96
#define ACT_BARREL_CABB_HARDER  100
#define ACT_RED_JUMPER          101
#define ACT_BOSS                102
#define ACT_PIPE_OUTLET         104
#define ACT_PIPE_INLET          105
#define ACT_SUCTION_WALKER      106
#define ACT_TRANSPORTER_1       107
#define ACT_TRANSPORTER_2       108
#define ACT_PROJECTILE_W        109
#define ACT_PROJECTILE_E        110
#define ACT_SPIT_WALL_PLANT_E   111
#define ACT_SPIT_WALL_PLANT_W   112
#define ACT_SPITTING_TURRET     113
#define ACT_SCOOTER             114
#define ACT_BASKET_PEA_PILE     115
#define ACT_BASKET_LUMPY_FRUIT  116
#define ACT_BARREL_HORN         117
#define ACT_RED_CHOMPER         118
#define ACT_BASKET_POD          119
#define ACT_SWITCH_LIGHTS       120
#define ACT_SWITCH_FORCE_FIELD  121
#define ACT_FORCE_FIELD_VERT    122
#define ACT_FORCE_FIELD_HORIZ   123
#define ACT_PINK_WORM           124
#define ACT_HINT_GLOBE_0        125
#define ACT_PUSHER_ROBOT        126
#define ACT_SENTRY_ROBOT        127
#define ACT_PINK_WORM_SLIME     128
#define ACT_DRAGONFLY           129
#define ACT_WORM_CRATE          130
#define ACT_BOTTLE_DRINK        134
#define ACT_GRN_GOURD           135
#define ACT_BLU_SPHERES         136
#define ACT_POD                 137
#define ACT_PEA_PILE            138
#define ACT_LUMPY_FRUIT         139
#define ACT_HORN                140
#define ACT_RED_BERRIES         141
#define ACT_BARREL_BOTL_DRINK   142
#define ACT_SATELLITE           143
#define ACT_IVY_PLANT           145
#define ACT_YEL_FRUIT_VINE      146
#define ACT_HEADDRESS           147
#define ACT_BASKET_HEADDRESS    148
#define ACT_EXIT_MONSTER_W      149
#define ACT_EXIT_LINE_VERT      150
#define ACT_SMALL_FLAME         151
#define ACT_TULIP_LAUNCHER      152
#define ACT_ROTATING_ORNAMENT   153
#define ACT_BLU_CRYSTAL         154
#define ACT_RED_CRYSTAL_FLOOR   155
#define ACT_BARREL_RT_ORNAMENT  156
#define ACT_BARREL_BLU_CRYSTAL  157
#define ACT_BARREL_RED_CRYSTAL  158
#define ACT_GRN_TOMATO_FLOAT    159
#define ACT_RED_TOMATO_FLOAT    160
#define ACT_YEL_PEAR_FLOAT      161
#define ACT_BEAR_TRAP           162
#define ACT_FALLING_FLOOR       163
#define ACT_EP1_END_1           164
#define ACT_EP1_END_2           165
#define ACT_EP1_END_3           166
#define ACT_BASKET_ROOT         167
#define ACT_ROOT                168
#define ACT_BASKET_RG_BERRIES   169
#define ACT_REDGRN_BERRIES      170
#define ACT_BASKET_RED_GOURD    171
#define ACT_RED_GOURD           172
#define ACT_BARREL_GRN_EMERALD  173
#define ACT_GRN_EMERALD         174
#define ACT_BARREL_CLR_DIAMOND  175
#define ACT_CLR_DIAMOND         176
#define ACT_SCORE_EFFECT_100    177
#define ACT_SCORE_EFFECT_200    178
#define ACT_SCORE_EFFECT_400    179
#define ACT_SCORE_EFFECT_800    180
#define ACT_SCORE_EFFECT_1600   181
#define ACT_SCORE_EFFECT_3200   182
#define ACT_SCORE_EFFECT_6400   183
#define ACT_SCORE_EFFECT_12800  184
#define ACT_EXIT_PLANT          186
#define ACT_BIRD                187
#define ACT_ROCKET              188
#define ACT_INVINCIBILITY_CUBE  189
#define ACT_PEDESTAL_SMALL      190
#define ACT_PEDESTAL_MEDIUM     191
#define ACT_PEDESTAL_LARGE      192
#define ACT_BARREL_CYA_DIAMOND  193
#define ACT_CYA_DIAMOND         194
#define ACT_BARREL_RED_DIAMOND  195
#define ACT_RED_DIAMOND         196
#define ACT_BARREL_GRY_OCTAHED  197
#define ACT_GRY_OCTAHEDRON      198
#define ACT_BARREL_BLU_EMERALD  199
#define ACT_BLU_EMERALD         200
#define ACT_INVINCIBILITY_BUBB  201
#define ACT_THRUSTER_JET        202
#define ACT_EXIT_TRANSPORTER    203
#define ACT_HINT_GLOBE_1        204
#define ACT_HINT_GLOBE_2        205
#define ACT_HINT_GLOBE_3        206
#define ACT_HINT_GLOBE_4        207
#define ACT_HINT_GLOBE_5        208
#define ACT_HINT_GLOBE_6        209
#define ACT_HINT_GLOBE_7        210
#define ACT_HINT_GLOBE_8        211
#define ACT_HINT_GLOBE_9        212
#define ACT_CYA_DIAMOND_FLOAT   213
#define ACT_RED_DIAMOND_FLOAT   214
#define ACT_GRY_OCTAHED_FLOAT   215
#define ACT_BLU_EMERALD_FLOAT   216
#define ACT_JUMP_PAD_CEIL       217
#define ACT_BARREL_HEADPHONES   218
#define ACT_HEADPHONES_FLOAT    219
#define ACT_HEADPHONES          220
#define ACT_FROZEN_DN           221
#define ACT_BANANAS             223
#define ACT_BASKET_RED_LEAFY    224
#define ACT_RED_LEAFY_FLOAT     225
#define ACT_RED_LEAFY           226
#define ACT_BASKET_BRN_PEAR     227
#define ACT_BRN_PEAR_FLOAT      228
#define ACT_BRN_PEAR            229
#define ACT_BASKET_CANDY_CORN   230
#define ACT_CANDY_CORN_FLOAT    231
#define ACT_CANDY_CORN          232
#define ACT_FLAME_PULSE_W       233
#define ACT_FLAME_PULSE_E       234
#define ACT_SPEECH_OUCH         235
#define ACT_RED_SLIME_THROB     236
#define ACT_RED_SLIME_DRIP      237
#define ACT_HINT_GLOBE_10       238
#define ACT_HINT_GLOBE_11       239
#define ACT_HINT_GLOBE_12       240
#define ACT_HINT_GLOBE_13       241
#define ACT_HINT_GLOBE_14       242
#define ACT_HINT_GLOBE_15       243
#define ACT_SPEECH_WHOA         244
#define ACT_SPEECH_UMPH         245
#define ACT_SPEECH_WOW_50K      246
#define ACT_EXIT_MONSTER_N      247
#define ACT_SMOKE_EMIT_SMALL    248
#define ACT_SMOKE_EMIT_LARGE    249
#define ACT_EXIT_LINE_HORIZ     250
#define ACT_CABBAGE_HARDER      251
#define ACT_RED_CRYSTAL_CEIL    252
#define ACT_HINT_GLOBE_16       253
#define ACT_HINT_GLOBE_17       254
#define ACT_HINT_GLOBE_18       255
#define ACT_HINT_GLOBE_19       256
#define ACT_HINT_GLOBE_20       257
#define ACT_HINT_GLOBE_21       258
#define ACT_HINT_GLOBE_22       259
#define ACT_HINT_GLOBE_23       260
#define ACT_HINT_GLOBE_24       261
#define ACT_HINT_GLOBE_25       262
#define ACT_POWER_UP            263
#define ACT_STAR                264
#define ACT_EP2_END_LINE        265

Defines meaningful names for each actor type defined in the game.

ACT_BASKET_NULL is a special sentinel value for the spawner functions and cannot be expressed in the map format. ACT_STAR_FLOAT has the value 32 in the map format, and all other actor types follow sequentially.

`CPUTYPE_*`

#define CPUTYPE_8088  0  /* Intel 8088 */
#define CPUTYPE_8086  1  /* Intel 8086 */
#define CPUTYPE_V20   2  /* NEC V20 */
#define CPUTYPE_V30   3  /* NEC V30 */
#define CPUTYPE_80188 4  /* Intel 80188 */
#define CPUTYPE_80186 5  /* Intel 80186 */
#define CPUTYPE_80286 6  /* Intel 80286 */
#define CPUTYPE_80386 7  /* Intel 80386 or above */

Provides meaningful names for the detected processor type.

These are the return values for the GetProcessorType() function.

`DEMOSTATE_*`

#define DEMOSTATE_NONE   0
#define DEMOSTATE_RECORD 1
#define DEMOSTATE_PLAY   2

Defines constant values that represent the input processing mode that should be used by the game loop.

Symbolic Constant	Value	Description
`DEMOSTATE_NONE`	0	The game is played in the usual way, with user keyboard input controlling the player. All in-game hints and intermission screens are displated.
`DEMOSTATE_RECORD`	1	The game is played in demo recording mode. The keyboard controls the player, but the level progression is altered and in-game hints are skipped. All player movement is captured into a demo file on disk.
`DEMOSTATE_PLAY`	2	The game runs in demo playback mode. Keyboard input is ignored (any keypress ends the game) and player movement commands are read from the demo file. Level progression and hint display are altered in the same way as with `DEMOSTATE_RECORD`.

These are the return values for the TitleLoop() function.

`DRAWMODE_*`

#define DRAWMODE_NORMAL      0
#define DRAWMODE_HIDDEN      1
#define DRAWMODE_WHITE       2
#define DRAWMODE_TRANSLUCENT 3
#define DRAWMODE_FLIPPED     4
#define DRAWMODE_IN_FRONT    5
#define DRAWMODE_ABSOLUTE    6

Defines the drawing modes available for the sprite drawing functions.

Symbolic Constant	Value	Description
`DRAWMODE_NORMAL`	0	Draw the sprite unmodified, with X/Y positions measured relative to the game world. If the map data contains a “draw in front” tiles that intersect the sprite, the map tiles will prevail.
`DRAWMODE_HIDDEN`	1	Do not draw any part of the sprite.
`DRAWMODE_WHITE`	2	Same as `DRAWMODE_NORMAL`, but all opaque pixel positions in the sprite are drawn in bright white.
`DRAWMODE_TRANSLUCENT`	3	Same as `DRAWMODE_WHITE`, but the sprite color is translucent.
`DRAWMODE_FLIPPED`	4	Same as `DRAWMODE_NORMAL`, but the sprite is drawn flipped vertically.
`DRAWMODE_IN_FRONT`	5	Same as `DRAWMODE_NORMAL`, but the sprite will cover all map tiles, regardless of their “draw in front” attribute.
`DRAWMODE_ABSOLUTE`	6	Draw the sprite unmodified, with X/Y positions measured relative to the screen. Since there is no relationship to the game world in this mode, “draw in front” attributes from the map (if present) have no effect.

`EGA_OFFSET_*`

#define EGA_OFFSET_SOLID_TILES  0x4000
#define EGA_OFFSET_STATUS_TILES 0x8000
#define EGA_OFFSET_BACKDROP_0_0 0xa300
#define EGA_OFFSET_BACKDROP_4_0 0xb980
#define EGA_OFFSET_BACKDROP_0_4 0xd000
#define EGA_OFFSET_BACKDROP_4_4 0xe680

Defines a number of useful EGA memory offsets relative to the adapter’s segment address (A000h). Every byte of address space here represents four actual bytes in the EGA’s memory, due to the separation of color planes.

`END_ANIMATION`

#define END_ANIMATION BYTE_MAX

Defines the marker that terminates palette animation tables. In Turbo C, this value is FFh.

`END_SCREEN`

#define END_SCREEN "END1.MNI"  /* episode 1, or */
#define END_SCREEN "END2.MNI"  /* episode 2, or */
#define END_SCREEN "END3.MNI"  /* episode 3 */

Defines the group file entry name of the full-screen image to show when the game has been won.

`FILENAME_BASE`

#define FILENAME_BASE "COSMO1"  /* episode 1, or */
#define FILENAME_BASE "COSMO2"  /* episode 2, or */
#define FILENAME_BASE "COSMO3"  /* episode 3 */

Defines the base file name (without extension) used for the group, configuration, and save files.

`FONT_*`

#define FONT_UP_ARROW        0x0050
#define FONT_LOWER_BAR_0     0x0140
#define FONT_UPPER_BAR_0     0x0168
#define FONT_0               0x0410
#define FONT_LOWER_A         0x0ac8
#define FONT_UPPER_BAR_1     0x0ed8
#define FONT_LOWER_BAR_1     0x0f00
#define FONT_BACKGROUND_GRAY 0x0f28

Provides meaningful names for some, but not all, of the font tile graphics.

The game font is built from 100 masked tiles, each beginning on a 40-byte boundary. Only a handful of these tiles are referenced directly in the game code; all other tile offsets are calculated by adding a multiple of 40 to one of the above base values.

`GAME_VERSION`

#define GAME_VERSION "1.20"

Holds a string value which represents the current released version of the game. For centering purposes, this should be four characters long.

`HELP_MENU_*`

#define HELP_MENU_CONTINUE 0
#define HELP_MENU_RESTART  1
#define HELP_MENU_QUIT     2

Defines the possible return values of the in-game help menu.

Symbolic Constant	Value	Description
`HELP_MENU_CONTINUE`	0	The user did not do anything that would affect the current iteration of the game loop or the state of gameplay as a whole.
`HELP_MENU_RESTART`	1	The user loaded a saved game, and the game loop needs to restart from the beginning with this new state.
`HELP_MENU_QUIT`	2	The user wants to quit the current game, and the game loop needs to stop running.

These are the return values for the ShowHelpMenu() function.

`IMAGE_*`

#define IMAGE_PRETITLE   0
#define IMAGE_TITLE      1
#define IMAGE_CREDITS    2
#define IMAGE_BONUS      3
#define IMAGE_END        4
#define IMAGE_ONE_MOMENT 5
#define IMAGE_TILEATTR   0x1111
#define IMAGE_DEMO       0xfff1
#define IMAGE_NONE       0xffff

Provides meaningful names for various full-screen image files.

The names are described in more detail on the full-screen image database page.

The values for IMAGE_TILEATTR, IMAGE_DEMO, and IMAGE_NONE do not refer to actual files that can be displayed; they are flags placed into miscDataContents to facilitate skipping load operations on data that may already be in memory.

`JOYSTICK_*`

#define JOYSTICK_A 1
#define JOYSTICK_B 2

Identifiers for joystick 1 (A) and 2 (B). JOYSTICK_B is not used by name anywhere in the game.

`JoystickState`

typedef struct {
    bool button1;
    bool button2;
} JoystickState;

Holds the state of two buttons (button1 and button2) on a single joystick. The values are true if the corresponding button is currently pressed, or false if it is unpressed.

`MAX_ACTORS`

#define MAX_ACTORS 410

Controls the size of the global actor state array, and governs the maximum number of actors that can be present on a map at any given time.

`MAX_LIGHTS`

#define MAX_LIGHTS 200

Controls the size of the global lights array, and governs the maximum number of lights that can be present on a map at any given time.

`enum MODE1_COLORS`

enum MODE1_COLORS {
    MODE1_BLACK = BLACK, MODE1_BLUE, MODE1_GREEN, MODE1_CYAN,
    MODE1_RED, MODE1_MAGENTA, MODE1_BROWN, MODE1_LIGHTGRAY,
    MODE1_DARKGRAY = DARKGRAY + 8, MODE1_LIGHTBLUE, MODE1_LIGHTGREEN,
    MODE1_LIGHTCYAN, MODE1_LIGHTRED, MODE1_LIGHTMAGENTA, MODE1_YELLOW,
    MODE1_WHITE
};

Defines the colors available for the EGA “display mode 1” palette. Display mode 1 is used in all 200-line modes (like the mode used by this game) and only supports the 16 RGBI output combinations.

The colors here are based on the Borland enum COLORS members, with the “light” variants shifted by 8 to compensate for the EGA’s color requirements. See SetPaletteRegister() for more information about this difference.

`MUSIC_*`

#define MUSIC_CAVES   0
#define MUSIC_SCARRY  1
#define MUSIC_BOSS    2
#define MUSIC_RUNAWAY 3
#define MUSIC_CIRCUS  4
#define MUSIC_TEKWRD  5
#define MUSIC_EASYLEV 6
#define MUSIC_ROCKIT  7
#define MUSIC_HAPPY   8
#define MUSIC_DEVO    9
#define MUSIC_DADODA  10
#define MUSIC_BELLS   11
#define MUSIC_DRUMS   12
#define MUSIC_BANJO   13
#define MUSIC_EASY2   14
#define MUSIC_TECK2   15
#define MUSIC_TECK3   16
#define MUSIC_TECK4   17
#define MUSIC_ZZTOP   18

Provides meaningful names for all of the music available in the game.

`Music`

typedef struct {
    word length;
    word datahead;
} Music;

Holds the length in bytes and first word of music data (datahead). Memory blocks that are cast to this structure type are generally much larger than the struct, and reading beyond datahead is typical and expected.

`PALANIM_*`

#define PALANIM_NONE       0
#define PALANIM_LIGHTNING  1
#define PALANIM_R_Y_W      2
#define PALANIM_R_G_B      3
#define PALANIM_MONO       4
#define PALANIM_W_R_M      5
#define PALANIM_EXPLOSIONS 6

Provides meaningful names for all of the palette animation types available in the game.

`PLAYER_*`

#define PLAYER_WALK_1         0
#define PLAYER_WALK_2         1
#define PLAYER_WALK_3         2
#define PLAYER_WALK_4         3
#define PLAYER_STAND          4
#define PLAYER_LOOK_NORTH     5
#define PLAYER_LOOK_SOUTH     6
#define PLAYER_JUMP           7
#define PLAYER_FALL           8
#define PLAYER_CLING          9
#define PLAYER_CLING_OPPOSITE 10
#define PLAYER_CLING_NORTH    11
#define PLAYER_CLING_SOUTH    12
#define PLAYER_FALL_LONG      13
#define PLAYER_CROUCH         14
#define PLAYER_PAIN           15
#define PLAYER_FALL_SEVERE    16
#define PLAYER_PUSHED         17
#define PLAYER_STAND_BLINK    18
#define PLAYER_SHAKE_1        19
#define PLAYER_SHAKE_2        20
#define PLAYER_SHAKE_3        21
#define PLAYER_JUMP_LONG      22
#define PLAYER_DEAD_1         46
#define PLAYER_DEAD_2         47
#define PLAYER_HIDDEN         BYTE_MAX

Provides meaningful names for the player sprite frames available in the game.

Most of these values must be combined with one of the PLAYER_BASE_* constants to select between the west- and east-facing variants of each frame. The only exceptions are the “dead” and “hidden” values, which are directionless.

`PLAYER_BASE_*`

#define PLAYER_BASE_WEST 0
#define PLAYER_BASE_EAST 23

Defines the base frame number for the west- and east-facing sets of player sprites.

The values here should be added to one of the PLAYER_* constants to produce the true frame number for the desired combination.

`Platform`

typedef struct {
    word x;
    word y;
    word mapstash[5];
} Platform;

Holds the x and y position for a single platform. The mapstash[] array provides temporary storage space for the five map tiles that are swapped out as the platform’s tiles cover them.

Due to hard-coded offsets in LoadMapData() and MovePlatforms, the mapstash[] array must begin at word offset 2 in this structure.

`POUNCE_HINT_*`

#define POUNCE_HINT_UNSEEN 0
#define POUNCE_HINT_QUEUED 1
#define POUNCE_HINT_SEEN   2

Defines constants that represent the current state of the “jump on top of creatures…” hint message.

Symbolic Constant	Value	Description
`POUNCE_HINT_UNSEEN`	0	The hint has never been shown. If the player is hurt, it is appropriate to show the hint.
`POUNCE_HINT_QUEUED`	1	The player has just been hurt, and the hint needs to be shown. The hint message is queued for display when the current frame’s drawing is complete.
`POUNCE_HINT_SEEN`	2	The hint has been shown, or the player has demonstrated that they know how to pounce on enemies. All saved games are written with this pounce hint state, so all loaded games will suppress the hint.

`RESTORE_GAME_*`

#define RESTORE_GAME_NOT_FOUND 0
#define RESTORE_GAME_SUCCESS   1
#define RESTORE_GAME_ABORT     2

Defines constants that represent the possible outcomes of a user’s interaction with the “restore game” menu.

Symbolic Constant	Value	Description
`RESTORE_GAME_NOT_FOUND`	0	The user chose a valid save slot, but there was no file saved there.
`RESTORE_GAME_SUCCESS`	1	The restore completed successfully and the new game state is ready to play.
`RESTORE_GAME_ABORT`	2	The user aborted the restore procedure, either explicitly by pressing `Esc` or implicitly by choosing an invalid save slot.

These are the return values for the PromptRestoreGame() function.

`SAVE_SLOT_INDEX`

#define SAVE_SLOT_INDEX 9

Holds the (zero-indexed) position in the filename template string where save game slot numbers should be inserted.

In the official version of the game, the save file template is "COSMOx.SV " with x having a value between '1' and '3' depending on the episode. The ninth index of this string is a space character, which is replaced with the save slot character during calls to LoadGameState() and SaveGameState().

`SCANCODE_*`

#define SCANCODE_NULL        0x00
#define SCANCODE_ESC         0x01
#define SCANCODE_1           0x02  /* 1  ! */
#define SCANCODE_2           0x03  /* 2  @ */
#define SCANCODE_3           0x04  /* 3  # */
#define SCANCODE_4           0x05  /* 4  $ */
#define SCANCODE_5           0x06  /* 5  % */
#define SCANCODE_6           0x07  /* 6  ^ */
#define SCANCODE_7           0x08  /* 7  & */
#define SCANCODE_8           0x09  /* 8  * */
#define SCANCODE_9           0x0a  /* 9  ( */
#define SCANCODE_0           0x0b  /* 0  ) */
#define SCANCODE_MINUS       0x0c  /* -  _ */
#define SCANCODE_EQUAL       0x0d  /* =  + */
#define SCANCODE_BACKSPACE   0x0e
#define SCANCODE_TAB         0x0f
#define SCANCODE_Q           0x10  /* q  Q */
#define SCANCODE_W           0x11  /* w  W */
#define SCANCODE_E           0x12  /* e  E */
#define SCANCODE_R           0x13  /* r  R */
#define SCANCODE_T           0x14  /* t  T */
#define SCANCODE_Y           0x15  /* y  Y */
#define SCANCODE_U           0x16  /* u  U */
#define SCANCODE_I           0x17  /* i  I */
#define SCANCODE_O           0x18  /* o  O */
#define SCANCODE_P           0x19  /* p  P */
#define SCANCODE_LEFT_BRACE  0x1a  /* [  { */
#define SCANCODE_RIGHT_BRACE 0x1b  /* ]  } */
#define SCANCODE_ENTER       0x1c
#define SCANCODE_CTRL        0x1d
#define SCANCODE_A           0x1e  /* a  A */
#define SCANCODE_S           0x1f  /* s  S */
#define SCANCODE_D           0x20  /* d  D */
#define SCANCODE_F           0x21  /* f  F */
#define SCANCODE_G           0x22  /* g  G */
#define SCANCODE_H           0x23  /* h  H */
#define SCANCODE_J           0x24  /* j  J */
#define SCANCODE_K           0x25  /* k  K */
#define SCANCODE_L           0x26  /* l  L */
#define SCANCODE_SEMICOLON   0x27  /* ;  : */
#define SCANCODE_APOSTROPHE  0x28  /* '  " */
#define SCANCODE_GRAVE       0x29  /* `  ~ */
#define SCANCODE_LEFT_SHIFT  0x2a
#define SCANCODE_BACKSLASH   0x2b  /* \  | */
#define SCANCODE_Z           0x2c  /* z  Z */
#define SCANCODE_X           0x2d  /* x  X */
#define SCANCODE_C           0x2e  /* c  C */
#define SCANCODE_V           0x2f  /* v  V */
#define SCANCODE_B           0x30  /* b  B */
#define SCANCODE_N           0x31  /* n  N */
#define SCANCODE_M           0x32  /* m  M */
#define SCANCODE_COMMA       0x33  /* ,  < */
#define SCANCODE_DOT         0x34  /* .  > */
#define SCANCODE_SLASH       0x35  /* /  ? */
#define SCANCODE_RIGHT_SHIFT 0x36
#define SCANCODE_KP_ASTERISK 0x37  /* *  PrtSc */
#define SCANCODE_ALT         0x38
#define SCANCODE_SPACE       0x39
#define SCANCODE_CAPS_LOCK   0x3a
#define SCANCODE_F1          0x3b
#define SCANCODE_F2          0x3c
#define SCANCODE_F3          0x3d
#define SCANCODE_F4          0x3e
#define SCANCODE_F5          0x3f
#define SCANCODE_F6          0x40
#define SCANCODE_F7          0x41
#define SCANCODE_F8          0x42
#define SCANCODE_F9          0x43
#define SCANCODE_F10         0x44
#define SCANCODE_NUM_LOCK    0x45
#define SCANCODE_SCROLL_LOCK 0x46
#define SCANCODE_KP_7        0x47  /* Home         7 */
#define SCANCODE_KP_8        0x48  /* Up Arrow     8 */
#define SCANCODE_KP_9        0x49  /* Pg Up        9 */
#define SCANCODE_KP_MINUS    0x4a  /*              - */
#define SCANCODE_KP_4        0x4b  /* Left Arrow   4 */
#define SCANCODE_KP_5        0x4c  /*              5 */
#define SCANCODE_KP_6        0x4d  /* Right Arrow  6 */
#define SCANCODE_KP_PLUS     0x4e  /*              + */
#define SCANCODE_KP_1        0x4f  /* End          1 */
#define SCANCODE_KP_2        0x50  /* Down Arrow   2 */
#define SCANCODE_KP_3        0x51  /* Pg Down      3 */
#define SCANCODE_KP_0        0x52  /* Ins          0 */
#define SCANCODE_KP_DOT      0x53  /* Del          . */
#define SCANCODE_SYS_REQ     0x54
#define SCANCODE_F11         0x57
#define SCANCODE_F12         0x58
#define SCANCODE_EXTENDED    0xe0

Provides meaningful names for all of the IBM PC/AT keyboard scancodes. These are all well-defined and well-known.

`SCROLLH`

#define SCROLLH 18

The height of the scrolling view into the game world, in tiles.

`SCROLLW`

#define SCROLLW 38

The width of the scrolling view into the game world, in tiles.

`SND_*`

#define SND_BIG_PRIZE           1
#define SND_PLAYER_JUMP         2
#define SND_PLAYER_LAND         3
#define SND_PLAYER_CLING        4
#define SND_PLAYER_HIT_HEAD     5
#define SND_PLAYER_POUNCE       6
#define SND_PLAYER_DEATH        7
#define SND_DOOR_UNLOCK         8
#define SND_SPIKES_MOVE         9
#define SND_EXPLOSION           10
#define SND_WIN_LEVEL           11
#define SND_BARREL_DESTROY_1    12
#define SND_PRIZE               13
#define SND_PLAYER_HURT         14
#define SND_FOOT_SWITCH_MOVE    15
#define SND_FOOT_SWITCH_ON      16
#define SND_ROAMER_GIFT         17
#define SND_DESTROY_SATELLITE   18
#define SND_PLAYER_FOOTSTEP     19
#define SND_PUSH_PLAYER         20
#define SND_DRIP                21
#define SND_PIPE_CORNER_HIT     22
#define SND_TRANSPORTER_ON      23
#define SND_SCOOTER_PUTT        24
#define SND_DESTROY_SOLID       25
#define SND_PROJECTILE_LAUNCH   26
#define SND_BIG_OBJECT_HIT      27
#define SND_NO_BOMBS            28
#define SND_PLACE_BOMB          29
#define SND_HINT_DIALOG_ALERT   30
#define SND_RED_JUMPER_JUMP     31
#define SND_RED_JUMPER_LAND     32
#define SND_BGHOST_EGG_CRACK    33
#define SND_BGHOST_EGG_HATCH    34
#define SND_SAW_BLADE_MOVE      35
#define SND_FIREBALL_LAUNCH     36
#define SND_OBJECT_HIT          37
#define SND_EXIT_MONSTER_OPEN   38
#define SND_EXIT_MONSTER_INGEST 39
#define SND_BEAR_TRAP_CLOSE     40
#define SND_PAUSE_GAME          41
#define SND_WEEEEEEEE           42
#define SND_JUMP_PAD_ROBOT      43
#define SND_TEXT_TYPEWRITER     44
#define SND_BONUS_STAGE         45
#define SND_SHARD_BOUNCE        46
#define SND_TULIP_LAUNCH        47
#define SND_NEW_GAME            48
#define SND_ROCKET_BURN         49
#define SND_SMASH               50
#define SND_HIGH_SCORE_DISPLAY  51
#define SND_HIGH_SCORE_SET      52
#define SND_IVY_PLANT_RISE      53
#define SND_FLAME_PULSE         54
#define SND_BOSS_DAMAGE         55
#define SND_BOSS_MOVE           56
#define SND_SPEECH_BUBBLE       57
#define SND_BABY_GHOST_JUMP     58
#define SND_BABY_GHOST_LAND     59
#define SND_THUNDER             60
#define SND_BARREL_DESTROY_2    61
#define SND_TULIP_INGEST        62
#define SND_PLANT_MOUTH_OPEN    63
#define SND_ENTERING_LEVEL_NUM  64
#define SND_BOSS_LAUNCH         65

Provides meaningful names for all of the PC speaker sound effects included with the game.

These constants should be passed to StartSound() to start playing a PC speaker sound effect. Each sound number is described in more detail on the sound database page.

`TILE_*`

#define TILE_EMPTY              0x0000
#define TILE_INVISIBLE_PLATFORM 0x0048
#define TILE_STRIPED_PLATFORM   0x0050
#define TILE_SWITCH_FREE_1N     0x3d68
#define TILE_SWITCH_BLOCK_1     0x3d88
#define TILE_SWITCH_BLOCK_2     0x3d90
#define TILE_SWITCH_BLOCK_3     0x3d98
#define TILE_SWITCH_BLOCK_4     0x3da0
#define TILE_SWITCH_FREE_1L     0x3da8
#define TILE_DOOR_BLOCK         0x3dc8
#define TILE_BLUE_PLATFORM      0x3dd0
#define TILE_MYSTERY_BLOCK_NW   0x3df8
#define TILE_MYSTERY_BLOCK_NE   0x3e00
#define TILE_MYSTERY_BLOCK_SW   0x3e08
#define TILE_MYSTERY_BLOCK_SE   0x3e10
#define TILE_WAIT_SPINNER_1     0x3e18
#define TILE_TXTFRAME_NORTHWEST 0x3e38
#define TILE_TXTFRAME_NORTHEAST 0x3e40
#define TILE_TXTFRAME_SOUTHWEST 0x3e48
#define TILE_TXTFRAME_SOUTHEAST 0x3e50
#define TILE_TXTFRAME_NORTH     0x3e58
#define TILE_TXTFRAME_SOUTH     0x3e60
#define TILE_TXTFRAME_WEST      0x3e68
#define TILE_TXTFRAME_EAST      0x3e70
#define TILE_DARK_GRAY          0x3e78
#define TILE_MASKED_0           0x3e80  /* aka 16,000 */

Provides meaningful names for certain map tile values.

For space reasons, some of the names are a bit obtuse:

TILE_SWITCH_FREE_1N has no (“N”) line at its top.
TILE_SWITCH_FREE_1L has a light-colored (“L”) line at its top.
Names that include EMPTY or FREE do not restrict movement, and essentially behave as “air.”
Names including PLATFORM only block movement in the southern direction. The player may jump up through them freely, but movement will stop if they land on it from above.
Names including BLOCK are solid, and block movement in all directions.
Names with a direction indicate that they are meant to be used in conjunction with other, similarly named tiles to draw larger constructions. The directions indicate the correct relative position for each tile.

`TITLE_SCREEN`

#define TITLE_SCREEN "TITLE1.MNI"  /* episode 1, or */
#define TITLE_SCREEN "TITLE2.MNI"  /* episode 2, or */
#define TITLE_SCREEN "TITLE3.MNI"  /* episode 3 */

Defines the group file entry name of the full-screen image to show during the main title sequence.

`WORD_MAX`

#define WORD_MAX 0xffffU

Constant holding the largest expressible 16-bit unsigned integer value, also known as a machine word.

`activeMusic`

Music *activeMusic;

Holds a pointer to the structure containing the length and data bytes of the most recent piece of music that has been started.

This is updated whenever StartGameMusic() or StartMenuMusic() is called, and read whenever the music needs to be restarted – for instance, after the game is paused and then unpaused.

This is a Music structure.

`activePage`

word activePage;

Holds the zero-indexed number (0 or 1) of the graphics page that is currently being shown on the screen.

This is only used during gameplay, where it will usually hold the opposite value that drawPageNumber has.

`activeSoundIndex`

word activeSoundIndex;

Holds the zero-indexed sound number of the PC speaker sound effect that is currently playing.

`activeSoundPriority`

word activeSoundPriority;

Holds the priority value of the PC speaker sound effect that is currently playing.

This is checked and updated during calls to StartSound(). If the new sound has a priority value that is less than activeSoundPriority, the new sound will not play and the currently-playing sound will continue.

`activeTransporter`

word activeTransporter;

Holds the number of the destination transporter when one is in use, or zero during normal gameplay.

This is the identifier of the transporter the player is moving to, but the test for this is rather simplistic. For each transporter in the map, if its “to address” data is different from activeTransporter, that transporter is the destination. This limits each map to having two transporters that ping-pong the player between them.

As a special case, a activeTransporter value of 3 will win the level, allowing for one or more Transporter Exits to be implemented separately from any other transporters on the map.

`actorTileData[]`

byte *actorTileData[3];

Points to masked tile image data used to draw actors, decorations, spawners, explosions, shards, and miscellaneous UI sprites.

Its allocations are divided into three distinct byte-aligned memory blocks due to the overall size of the data. The first two blocks each hold 65,535 bytes and the final block holds 60,840 bytes.

`areLightsActive`

bool areLightsActive;

When true, any lights present on the map are enabled.

On most maps, this variable is set to true by default. It only becomes false if a Foot Switch (activates lights) is loaded into the map, and activation of that switch can set it true again. This variable also influences the behavior of Sentry Robots: when false, the do not shoot at the player.

Related to hasLightSwitch.

`backdropTable[]`

word backdropTable[2880];

A lookup table containing 2,880 words of precalculated offset data used for drawing the in-game parallax scrolling backdrop.

This is also used as scratch storage during calls to DrawFullscreenText().

`blockActionCmds`

bool blockActionCmds;

When true, prevents the player from moving, being hurt, or being drawn.

This variable takes a true value when the player is “removed” from the map, like when interacting with a Tulip Launcher Plant, Exit Monster, Exit Plant, or the E1L11 Exit Monster.

`cartoonInfoData`

word *cartoonInfoData;

Points to a block of memory containing tile info data (widths, heights, and offsets) for cartoon sprites.

`cmdBomb`

bbool cmdBomb;

Controls the state of the player’s “drop bomb” action command.

`cmdEast`

bbool cmdEast;

Controls the state of the player’s “walk east” movement command.

`cmdJump`

bbool cmdJump;

Controls the state of the player’s “jump” movement command.

`cmdNorth`

bbool cmdNorth;

Controls the state of the player’s “look north” action command.

`cmdSouth`

bbool cmdSouth;

Controls the state of the player’s “look south” action command.

`cmdWest`

bbool cmdWest;

Controls the state of the player’s “walk west” movement command.

`demoDataLength`

word demoDataLength;

Holds the size, in bytes, of the demo data currently loaded into memory.

`demoDataPos`

word demoDataPos;

Holds the byte offset of the current read/write position within the demo data while playing/recording a demo.

`demoState`

byte demoState;

Indicates the current state of input handling for gameplay.

This variable can hold one of the following values while the game is running:

Symbolic Constant	Value	Description
`DEMOSTATE_NONE`	0	Game is being played interactively, no demo is being recorded or played.
`DEMOSTATE_RECORD`	1	Game is being played interactively, and demo data is being recorded from the input.
`DEMOSTATE_PLAY`	2	Game is being controlled by demo data.

When set to DEMOSTATE_RECORD or DEMOSTATE_PLAY, this suppresses the “Now entering level” message and all in-game hints, and adds a “DEMO” overlay.

`drawPageNumber`

word drawPageNumber;

Holds the zero-indexed number (0 or 1) of the graphics page that the drawing procedures will operate on.

During gameplay (where double-buffering is used) activePage will usually hold the opposite value, preventing changes from becoming visible on the screen until the pages are flipped.

`drawPageSegment`

word drawPageSegment;

Holds the memory segment address of the graphics page that the drawing procedures will operate on.

`enableAdLib`

bool enableAdLib;

When true, this permits the AdLib service to actually send music data to the AdLib hardware. When false, this inhibits these transfers, holding the AdLib hardware “frozen” in its current state.

`enableSpeaker`

bool enableSpeaker;

When true, this permits the PC speaker hardware to actually emit sounds. When false, this unconditionally silences the speaker output.

`fontTileData`

byte *fontTileData;

Points to a 4,000 byte block of memory used to hold masked tile image data for the UI font.

`fullscreenImageNames[]`

char *fullscreenImageNames[] = {
    "PRETITLE.MNI", TITLE_SCREEN, "CREDIT.MNI", "BONUS.MNI", END_SCREEN,
    "ONEMOMNT.MNI"
};

Holds a list of all group file entry names that refer to full-screen image data.

The values for TITLE_SCREEN and END_SCREEN are different depending on the episode; typically these will be "TITLEx.MNI" and "ENDx.MNI" (respectively) with x matching the episode number.

`gameScore`

dword gameScore;

Holds the number of points that the player has earned over the course of the current game.

Most events in the game add points to this variable. Its purpose is purely vanity, the only effect is to earn a spot in the high score table at the end of the game. The smallest score value implemented in the game is worth 100 points, and the score should always be a multiple of 50 unless e.g. a save file was manipulated.

The acceptable range of values for this variable is 0–9,999,999. Numbers with more than seven characters must be avoided, otherwise draw overflow issues will occur in the status bar.

`gameStars`

dword gameStars;

Holds the number of stars that the player has collected.

Each star represents a 1,000 point bonus which is added to gameScore during the ShowStarBonus() sequence. The star count is reset to zero once the bonus has been added. The star count also influences which bonus maps are entered over the course of the game:

Stars	Bonus Map
0–24	Skipped.
25–49	BONUS1 (E1), BONUS3 (E2), or BONUS5 (E3).
≥50	BONUS2 (E1), BONUS4 (E2), or BONUS6 (E3).

The acceptable range of values for this variable is 0–99. Numbers with two or more characters must be avoided, otherwise draw overflow issues will occur in the status bar.

`gameTickCount`

word gameTickCount;

Holds a running counter that increments precisely 140 times per second, regardless of the state of program execution.

This value is used by various delay functions to produce pauses of a constant length, regardless of processor speed. It is also used to govern the speed of the GameLoop function.

`hasLightSwitch`

bool hasLightSwitch;

When true, indicates that the current map has a switch that can control the lights.

This variable influences the behavior of Sentry Robots to help them differentiate if areLightsActive is true because there is no Foot Switch (activates lights) on the map, or because the switch is present and has been activated by the player.

`highScoreNames[]`

typedef char HighScoreName[16];
HighScoreName highScoreNames[11];

Points to the first element of an 11-element fixed-length string array. Each element is 16 bytes long, and holds one of the names on the high score table.

The table is arranged in score order, from highest score to lowest.

`highScoreValues[]`

dword highScoreValues[11];

Points to the first element of an 11-element numeric array. Each element is a doubleword value, and holds one of the scores on the high score table.

The table is arranged in score order, from highest score to lowest.

`isAdLibPresent`

bbool isAdLibPresent;

Holds a true value if an AdLib card was detected in the system, and false otherwise.

This variable directly mirrors the state of the hardware and cannot be influenced by any in-game setting. This affects the behavior of memory allocation for the tileAttributeData pointer.

`isAdLibPresentPrivate`

bool isAdLibPresentPrivate;

Holds a true value if an AdLib card was detected in the system, and false otherwise.

This is a duplicate (but separately managed) copy of isAdLibPresent. This is used internally by the AdLib functions only.

`isAdLibServiceRunning`

bool isAdLibServiceRunning;

Holds a true value if the system timer is running at the faster AdLib rate and the AdLib service is being called. Otherwise, holds false to indicate that the timer is running slowly and only the PC speaker service is being called.

`isAdLibStarted`

bool isAdLibStarted;

Holds a true value if the AdLib startup code has executed, and false if the AdLib has either never been started or was explicitly stopped.

This variable is managed by StartAdLib() and StopAdLib() to ensure no attempts are made to start an already-started AdLib card or stop an already-stopped one.

`isCartoonDataLoaded`

bbool isCartoonDataLoaded;

Holds a true value if the cartoon tile image data has been loaded into the shared memory. When false, this memory is either uninitialized or contains map data.

This is checked by DrawCartoon() to determine if the cartoon data needs to be loaded from disk, avoiding an extra disk access if so. The memory area used for cartoon images (or map data) is mapData.

`isDebugMode`

bbool isDebugMode;

Holds a true value if the debug mode has been activated by the player, and false during normal gameplay.

This can be toggled while in a game by pressing Tab+F12+Del. It cannot be toggled in the menus.

Debug mode has the following effects:

In the game, enables the F10+___ cheat codes.
In the main menu, adds the ability to press F11 to begin recording a demo.
At all times, adds the ability to press Alt+C to call the system’s original keyboard interrupt handler.

`isGodMode`

bool isGodMode;

Holds a true value if the god mode has been activated by using the debug keys, and false during normal gameplay.

If isDebugMode is true, this can be toggled while in a game by pressing F10+G.

God mode makes the player invincible to any damage that would deduct health. The player can still die by falling off bottom of the map.

`isInGame`

bbool isInGame;

Holds a true value if a game is currently being played, and false if the main menu is being shown.

This controls whether or not ShowHighScoreTable() clears the screen before and after showing.

`isJoystickReady`

bool isJoystickReady;

Controls whether game input should come from the keyboard or the joystick.

When true, ProcessGameInput only accepts player movement from the joystick. When false, player movement is only accepted from the keyboard.

Entering the “joystick redefine” menu and completing the calibration process sets this value to true. Merely entering the “keyboard redefine” menu sets this value to false.

`isKeyDown[]`

bbool isKeyDown[255];

Holds the down/up state of each keyboard key. Elements are indexed by the key’s “make” code, and each element holds a true value if the key is down and false if it is up.

This array is twice as large as it needs to be. Due to the high bit being used as the make/break flag, only 128 keys can actually be encoded by the keyboard controller’s input buffer. Elements 128–255 of this array can never hold true values.

`isMusicEnabled`

bool isMusicEnabled;

Controls whether or not the AdLib music should be sent to the hardware.

Music may play when this is true, and music is silenced when false. This setting can be toggled by the user, and the value is persisted in the configuration file.

`isNewGame`

bbool isNewGame;

Holds a true value if the game loop was started via the “Begin New Game” menu option, and false in all other cases (load game or demo mode).

This is set in TitleLoop() and controls whether SwitchLevel displays a “One Moment” image before loading the first level.

`isNewSound`

bool isNewSound;

Indicates that the currently-playing PC speaker sound effect has been changed.

This serves as a communication flag between StartSound() and PCSpeakerService().

`isSoundEnabled`

bool isSoundEnabled;

Controls whether or not the PC speaker sound effects should be sent to the hardware.

Sound effects may play when this is true, and sound effects are silenced when false. This setting can be toggled by the user, and the value is persisted in the configuration file.

`joinPathBuffer[]`

char joinPathBuffer[80];

Holds an 80-byte scratch area used for joining directory and file names into full path names.

`joystickBandBottom[]`

int joystickBandBottom[3];

Holds the timer values for the bottom edge of each joystick’s dead zone. Index 0 is unused; index 1 and 2 are for joystick 1 and 2, respectively.

`joystickBandLeft[]`

int joystickBandLeft[3];

Holds the timer values for the left edge of each joystick’s dead zone. Index 0 is unused; index 1 and 2 are for joystick 1 and 2, respectively.

`joystickBandRight[]`

int joystickBandRight[3];

Holds the timer values for the right edge of each joystick’s dead zone. Index 0 is unused; index 1 and 2 are for joystick 1 and 2, respectively.

`joystickBandTop[]`

int joystickBandTop[3];

Holds the timer values for the top edge of each joystick’s dead zone. Index 0 is unused; index 1 and 2 are for joystick 1 and 2, respectively.

`joystickBtn1Bombs`

bool joystickBtn1Bombs;

Controls which action the primary joystick button performs. When true, this button places a bomb. When false, this button makes the player jump. In either case, the secondary button takes the opposite action.

`keyNames[]`

typedef char KeyName[6];
KeyName keyNames[] = {
    "NULL", "ESC", "1", "2", "3", "4", "5", "6", "7", "8", "9", "0", "-",
    "=", "BKSP", "TAB", "Q", "W", "E", "R", "T", "Y", "U", "I", "O", "P",
    " ", " ", "ENTR", "CTRL", "A", "S", "D", "F", "G", "H", "J", "K", "L",
    ";", "\"", " ", "LSHFT", " ", "Z", "X", "C", "V", "B", "N", "M", ",",
    ".", "?", "RSHFT", "PRTSC", "ALT", "SPACE", "CAPLK", "F1", "F2", "F3",
    "F4", "F5", "F6", "F7", "F8", "F9", "F10", "NUMLK", "SCRLK", "HOME",
    "\x18", "PGUP", "-", "\x1B", "5", "\x1C", "+", "END", "\x19", "PGDN",
    "INS", "DEL", "SYSRQ", "", "", "F11", "F12", ""
};

Defines short (5 character or less) key name strings for the most common scancodes on the 84-key IBM PC/AT keyboard.

Generally keys are named using their base (unshifted) case, but all letters are stored capitalized. There are some exceptions and oddities:

NULL is not a key, and is generally indicative of an error condition. There shouldn’t be any circumstance in the game where this name is shown.
The keys [, ], `, and \ are defined as blank spaces. The game font does not contain any tiles for these characters or their shifted companions.
The ’ key renders as ", despite both characters being available in the game font.
The / key renders as ?.
The numeric keypad keys render as their non-numeric functions, if available.
The character codes 18h, 19h, 1Bh, and 1Ch produce the symbols ↑, ↓, ←, and → respectively.

`lastGroupEntryLength`

dword lastGroupEntryLength;

Holds the file size, in bytes, of the most recent group file entry that was opened.

This value is updated each time GroupEntryFp() opens a group file entry.

`lastScancode`

byte lastScancode;

Holds the most recent byte of data received by the system’s keyboard controller.

In the case of a key down/“make” code, this will be a value in the range 0h–7Fh. For key up/“break” codes, this will be a value in the range 80h–FFh. Break codes can be converted into corresponding make codes by taking the value bitwise-AND 7Fh.

In the case of multi-byte scancodes like those added with the 101-key PS/2 keyboard, this will only hold the most recent byte that was received.

`levelNum`

word levelNum;

Holds the current level number being played.

This is distinct from the map number – the level number tracks multiple plays through the bonus maps. The relationship between level and map progression is as follows:

Level Number	Map Number	Notes
0	1
1	2
2	Bonus A	The warp menu chooses this instance.
3	Bonus B	The warp menu chooses this instance.
4	3
5	4
6	Bonus A
7	Bonus B
8	5
9	6
10	Bonus A
11	Bonus B
12	7
13	8
14	Bonus A
15	Bonus B
16	9
17	10
18	Bonus A
19	Bonus B
20	11	Only present in episode 1.
21	12	Supported; never used.
22	Bonus A
23	Bonus B
24	13	Supported; never used.
25	14	Supported; never used.
26	Bonus A
27	Bonus B
28	15	Supported; never used.
29	16	Not supported; implementation incomplete.

`mapData`

union {
    byte *b;
    word *w;
} mapData;

Points to a 65,535 byte block of memory used to hold map data during the game OR temporary data in the main menu.

Maps are interpreted as word-aligned data, and temporary data is byte-aligned. This temporary data consists of masked tile image data for cartoons and scratch storage needed during the loading of backdrop images.

`mapNames[]`

#define MAP_NAMES { \
    "A1.MNI",  "A2.MNI",  "bonus1.mni", "bonus2.mni", \
    "A3.mni",  "A4.mni",  "bonus1.mni", "bonus2.mni", \
    "A5.mni",  "A6.mni",  "bonus1.mni", "bonus2.mni", \
    "A7.mni",  "A8.mni",  "bonus1.mni", "bonus2.mni", \
    "A9.mni",  "A10.mni", "bonus1.mni", "bonus2.mni", \
    "A11.mni", "A12.mni", "bonus1.mni", "bonus2.mni", \
    "A13.mni", "A14.mni", "bonus1.mni", "bonus2.mni", \
    "A15.mni", "A16.mni" \
}  /* episode 1, or */
#define MAP_NAMES { \
    "B1.MNI",  "B2.MNI",  "bonus3.mni", "bonus4.mni", \
    "B3.mni",  "B4.mni",  "bonus3.mni", "bonus4.mni", \
    "B5.mni",  "B6.mni",  "bonus3.mni", "bonus4.mni", \
    "B7.mni",  "B8.mni",  "bonus3.mni", "bonus4.mni", \
    "B9.mni",  "B10.mni", "bonus3.mni", "bonus4.mni", \
    "B11.mni", "B12.mni", "bonus3.mni", "bonus4.mni", \
    "B13.mni", "B14.mni", "bonus3.mni", "bonus4.mni", \
    "B15.mni", "B16.mni" \
}  /* episode 2, or */
#define MAP_NAMES { \
    "C1.MNI",  "C2.MNI",  "bonus5.mni", "bonus6.mni", \
    "C3.mni",  "C4.mni",  "bonus5.mni", "bonus6.mni", \
    "C5.mni",  "C6.mni",  "bonus5.mni", "bonus6.mni", \
    "C7.mni",  "C8.mni",  "bonus5.mni", "bonus6.mni", \
    "C9.mni",  "C10.mni", "bonus5.mni", "bonus6.mni", \
    "C11.mni", "C12.mni", "bonus5.mni", "bonus6.mni", \
    "C13.mni", "C14.mni", "bonus5.mni", "bonus6.mni", \
    "C15.mni", "C16.mni" \
}  /* episode 3 */
char *mapNames[] = MAP_NAMES;

Defines a list of the map file names corresponding to each level number in the game. Each episode includes higher-numbered maps that do not exist and cannot be reached.

`mapWidth`

word mapWidth;

Holds the width of the currently-loaded map, in tiles.

This is also the number of tiles that must be added or subtracted to reach a given horizontal position in the next or previous row of the map data. This is usually not used to stride over a fixed number of rows; see mapYPower for that.

`mapYPower`

word mapYPower;

Holds the width of the currently-loaded map, in tiles, expressed as 2 to the Nth power.

By expressing map width as 2ⁿ, it becomes possible to convert X,Y positions to linear tile offsets by calculating X + (Y << mapYPower). This is considerably faster than multiplying Y by mapWidth.

`maskedTileData`

byte *maskedTileData;

Points to a 40,000 byte block of memory used to hold masked tile image data during the game OR music data in the main menu.

`maxScrollY`

word maxScrollY;

Holds the largest allowable Y scroll position value for the current map.

This is not the same thing as map height; this is instead the height of the map minus the height of the game window. This is the largest possible value for scrollY before garbage begins to display at the bottom of the game window.

`miscData`

byte *miscData;

Points to a 35,000 byte block of memory used to hold a variety of different unrelated things.

Outside of gameplay, this is used as a temporary buffer while copying full-screen image data into EGA memory.

When switching maps, this is used as scratch storage during the loading of backdrop images.

During gameplay, the first 5,000 bytes of this block are used to hold any demo data that is being played or recorded. The remainder of the block is used to hold music data for the maps if there is an AdLib card installed, or tile attributes data if there is not an AdLib card installed. (See tileAttributeData.)

`miscDataContents`

word miscDataContents;

Provides an indication of the last data that was loaded into the miscellaneous data block.

When functions modify the contents of the miscData memory block, they also update this value with one of the IMAGE_* values to indicate what has been written there. This value is then used during DrawFullscreenImage() to skip loading in cases where miscData already contains the image content that is going to be drawn.

`musicDataHead`

word *musicDataHead;

Holds the memory address of the first word of the current music data. Used to rewind the music playback pointer each time the music loops.

`musicDataLeft`

word musicDataLeft;

Tracks the number of bytes of music data that still remain to be played. Once this value reaches zero, the music must restart from the beginning.

`musicDataLength`

word musicDataLength;

Tracks the total length of the current music data, in bytes.

`musicDataPtr`

word *musicDataPtr;

Points to the next word of music data that is going to be sent to the AdLib hardware.

`musicNames[]`

char *musicNames[] = {
    "mcaves.mni", "mscarry.mni", "mboss.mni", "mrunaway.mni",
    "mcircus.mni", "mtekwrd.mni", "measylev.mni", "mrockit.mni",
    "mhappy.mni", "mdevo.mni", "mdadoda.mni", "mbells.mni", "mdrums.mni",
    "mbanjo.mni", "measy2.mni", "mteck2.mni", "mteck3.mni", "mteck4.mni",
    "mzztop.mni"
};

Holds a list of all group file entry names that refer to music data.

Each array index matches with a MUSIC_* constant.

`musicNextDue`

dword musicNextDue;

Tracks the timestamp, in music ticks, when the next chunk of music is scheduled to be sent to the AdLib hardware.

`musicTickCount`

dword musicTickCount;

Tracks the current timestamp, in music ticks. Increments each time the AdLib service runs.

`numActors`

word numActors;

Holds the current number of utilized elements in the actors array.

This is used as an insertion cursor as actors are being created, pointing to the next available element where one could be inserted. It also is checked against MAX_ACTORS to prevent overflowing the array.

`numFountains`

word numFountains;

Holds the current number of utilized elements in the fountains array.

This is used as an insertion cursor as fountains are being created, pointing to the next available element where one could be inserted. This variable is not used for bounds checking, and overflow is possible with a malicious map file.

`numLights`

word numLights;

Holds the current number of utilized elements in the lights array.

This is used as an insertion cursor as lights are being created, pointing to the next available element where one could be inserted. It also is checked against MAX_LIGHTS to prevent overflowing the array.

`numPlatforms`

word numPlatforms;

Holds the current number of utilized elements in the platforms array.

This is used as an insertion cursor as platforms are being created, pointing to the next available element where one could be inserted. This variable is not used for bounds checking, and overflow is possible with a malicious map file.

`paletteAnimationNum`

byte paletteAnimationNum;

Holds the current palette animation number that was specified by the map being played.

`paletteStepCount`

dword paletteStepCount;

Holds the current position within the palette animation table.

Once the end of the palette table has been reached (as indicated by encountering an END_ANIMATION marker) this resets to 0 and the pattern repeats.

`pit0Value`

dword pit0Value;

Holds a copy of the most recent value used to reconfigure channel 0 of the system’s Programmable Interval Timer.

`playerBombs`

word playerBombs;

Holds the number of bombs the player is currently carrying.

The acceptable range of values for this variable is 0–9. Numbers with two or more characters must be avoided, otherwise draw overflow issues will occur in the status bar.

`playerHealth`

word playerHealth;

Holds the current amount of health the player has. Zero represents the immediate death of the player.

When a new game is started, this is initialized to 4, which represents three filled bars of health. It can decrement down to 1, representing all health bars unfilled. Once it decrements to zero, the player immediately dies.

The maximum amount of health obtainable, once all Hamburgers have been picked up, is 6.

`playerHealthCells`

word playerHealthCells;

Holds the number of health bar cells that are shown on the status bar. The player always has one unit of health more than the number of bar cells (i.e. the player is still alive if all the cells are unfilled).

When a new game is started, this is initialized to 3, which represents three available bars of health.

The maximum amount of health cells obtainable, once all Hamburgers have been picked up, is 5.

`playerHurtCooldown`

word playerHurtCooldown;

When greater than zero, makes the player temporarily invincible and flashes the sprite. Decrements toward zero during every frame of gameplay.

This is modified during calls to SetPIT0Value(), and takes the value that is passed during each call. It is treated as a 16-bit value in all contexts where it appears.

`playerInfoData`

word *playerInfoData;

Points to a block of memory containing tile info data (widths, heights, and offsets) for player sprites.

`playerPushFrame`

word playerPushFrame;

Specifies the frame of player sprite animation to show during a “push” sequence.

When the player is pushed by actors, this will be set to one of the “force-pushed” frames based on the relative position of the actor. In pipe systems, this will be PLAYER_HIDDEN to temporarily remove the player from the map.

`playerTileData`

byte *playerTileData;

Points to a block of memory matching the size and content of the PLAYERS.MNI group file entry, nominally 30,000 bytes.

This block is used to hold the masked tile image data that the player’s sprites are built from.

`pounceHintState`

word pounceHintState;

Holds a flag that tracks whether the user has been shown the “jump on top of creatures…” hint dialog.

At any time, the value of this variable should be one of the POUNCE_HINT_* values. The hint is shown the first time the player is hurt, even if the injury came from an un-pounceable actor.

`profCountCPU`

word profCountCPU;

Used temporarily during CPU profiling to track the number of busy loop iterations the CPU has performed so far.

This is updated when the ProfileCPUService() function runs, and interpreted during calculations in ProfileCPU().

`profCountPIT`

word profCountPIT;

Used temporarily during CPU profiling to track the number of timer interrupts that have been raised by the Programmable Interval Timer so far.

This is updated when the ProfileCPUService() function runs, and interpreted during calculations in ProfileCPU(). It is read during WaitWallclock(), but the actual value is irrelevant in that particular function.

`savedInt8`

typedef void interrupt (*InterruptFunction)(void);
InterruptFunction savedInt8;

Holds a reference to the old interrupt service routine for interrupt vector 8.

This function was the system timer interrupt handler when the program was started.

`savedInt9`

typedef void interrupt (*InterruptFunction)(void);
InterruptFunction savedInt9;

Holds a reference to the old interrupt service routine for interrupt vector 9.

This function was the keyboard handler when the program was started.

`sawBombHint`

bool sawBombHint;

Holds a true value if the user has seen the hint dialog teaching them about finding and using bombs. Defaults to false when a new game is started.

`sawHealthHint`

bool sawHealthHint;

Holds a true value if the user has seen the hint dialog teaching them about Power Up modules and their effect on player health. Defaults to false when a new game is started.

`scrollX`

word scrollX;

Holds the X coordinate of the map column currently positioned at the leftmost edge of the screen.

`scrollY`

word scrollY;

Holds the Y coordinate of the map row currently positioned at the topmost edge of the screen.