Notes:The Adventures of Captain Comic (DOS)

This page contains notes for the game The Adventures of Captain Comic (DOS).

Revisions

The Internet Archive has all five revisions under the item TheAdventuresOfCaptainComic:

• sw1988
• R2sw1988
• R3sw1989
• R4sw1989
• R5sw1991

It also has three other versions:

• swh11988 (file_id.diz labels it "Hacked/grafitti version 1")
• swh21988 (file_id.diz labels it "Hacked/grafitti version 2")
• R4a1sw1989 (file_id.diz labels it "Alternate version 1")

File Formats

Malvineous has documented the file formats here.

Executable Packing

In every revision, COMIC.EXE is packed with EXEPACK. Revision 1 uses an earlier version of EXEPACK that not all unpackers can handle. Try these ones:

• https://www.bamsoftware.com/software/exepack/
• https://github.com/w4kfu/unEXEPACK

R1swh21988 (a hacked version) doesn't have COMIC.EXE but rather MENU.EXE, and the EXEPACK layer appears to be wrapped in another layer that adds an advertisement for "Red Point".

Sound Effects

The format of a sound effect is an array of

struct {
    uint16_t freq_divider;
    uint16_t duration;
};

The 16-bit values are stored little-endian. Each freq_divider divides the Programmable Interval Timer base frequency of 1193182 Hz. For example, a freq_divider of 1c3f would result in an output frequency of 1193182 / 0x1c3f ≈ 165 Hz. The special freq_divider value 0028 indicates a rest. duration is in number of beats; each beat is about 55 ms (one tick of the 18.2 Hz IRQ 0 timer). The end of the sound is marked by a freq_divider of 0000.

Table of offsets to sound effects in the unpacked executable. Assumes that the unpacked executable has an EXE header of 512 bytes. Changed sounds are highlighted.

	R1sw1988	R1swh11988	R2sw1988	R3sw1989	R4a1sw1989	R4sw1989	R5sw1991
title	2521	2521	25a2	25d2	27a2	27a2	29c4
start	2665	2665	2bc0	2bf2	2daa	2d9e
door	eda9	eda9	f309	f339	f4f9	f4e9	fc29
player death	edd1	edd1	f331	f361	f521	f511	fc51
teleport	edf9	edf9	f359	f389	f549	f539	fc79
bonus	ee19	ee19	f379	f3a9	f569	f559	fc99
materialize	ee25	ee25	f385	f3b5	f575	f565	fca5
game over	ee85	ee85	f3e5	f415	f5d5	f5c5	fd05
screen transition	eede	eede	f43e	f46f	f62f	f61f	fd3f
lost life	eefe	eefe	f45e	f48f	f64f	f63f	fd5f
shoot	ef4e	ef4e	f4ae	f4de	f69e	f68e	fdae
enemy death	ef5a	ef5a	f4ba	f4ea	f6aa	f69a	fdba
player damaged	ef71	ef71	f4d1	f501	f6c1	f6b1	fdd1
item get	ef81	ef81	f4e1	f511	f6d1	f6c1	fde1
extra life	ef95	ef95	f4f5	f525	f6e5	f6d5	fdf5

Revision 2 @ 1498

Revision 3 @ 14b3

handle_falling_and_jumping: fe0e17cf dec byte [jump_counter] 740f je .L1 2e803e140001 cmp byte cs:[key_jump_state], 1 750b jne .L3 802e16cf07 sub byte [comic_y_vel], 7 ; still jumping upward eb04 jmp .L3 .L1: fe0617cf inc byte [jump_counter] ; jump_counter bottoms out at 1 | | .L3: a016cf mov al, byte [comic_y_vel] 8ac8 mov cl, al d0f8 sar al, 1 d0f8 sar al, 1 d0f8 sar al, 1 8bde mov bx, si ; bl = comic_y_pos, bh = comic_x_pos 02d8 add bl, al ; bl = comic_y_pos + comic_y_vel/8 7d02 jge .L4 ; hit the top of the screen? b300 mov bl, 0 .L4: | | 8bf3 mov si, bx ; comic_y_pos = max(0, comic_y_pos + comic_y_vel/8) 80fb11 cmp bl, 0x11 ; comic_y_pos >= 8.5 tiles? 7203 jb .L5 e946ff jmp comic_dies ; die from falling in a pit .L5: 803e3e0002 cmp byte [current_level_number], 2 ; is this the space level? 7503 jne .L6 80e902 sub cl, 2 ; if so, comic_y_vel += 3 .L6: 80c105 add cl, 5 ; otherwise, comic_y_vel += 5 80f918 cmp cl, 0x18 ; comic_y_vel > 23? 7c02 jl .L7 b117 mov cl, 0x17 ; maximum falling velocity is 23 .L7: 880e16cf mov byte [comic_y_vel], cl 8a0e15cf mov cl, byte [comic_x_momentum] check_key_left: 2e803e160001 cmp byte cs:[key_left_state], 1 750e jne check_key_right c60619cf05 mov byte [comic_facing], 5 ; face left ; comic_x_momentum = max(comic_x_momentum - 1, -5) fec9 dec cl 80f9fb cmp cl, -5 7d02 jge check_key_right b1fb mov cl, -5 check_key_right: 2e803e170001 cmp byte cs:[key_right_state], 1 750e jne .L8 c60619cf00 mov byte [comic_facing], 0 ; face right ; comic_x_momentum = min(comic_x_momentum + 1, +5) fec1 inc cl 80f905 cmp cl, +5 7e02 jle .L8 b105 mov cl, +5 .L8: 880e15cf mov byte [comic_x_momentum], cl check_move_left: 0ac9 or cl, cl ; comic_x_momentum < 0? 7d07 jge check_move_right fe0615cf inc byte [comic_x_momentum] e87d00 call comic_moves_left a015cf mov al, byte [comic_x_momentum] check_move_right: 0ac0 or al, al ; comic_x_momentum > 0? 7e07 jle check_for_head_bonk fe0e15cf dec byte [comic_x_momentum] e8cb00 call comic_moves_right check_for_head_bonk: 8bc6 mov ax, si ; al = comic_y_pos, ah = comic_x_pos e890f4 call lookup_tile_at_coordinates ; tile at player's head 8a164007 mov dl, byte [last_solid_tile] 3817 cmp byte [bx], dl ; is it solid? 7f0a jg in_ceiling f6c401 test ah, 1 ; is the player halfway between tiles? 740a je check_for_solid_ground 385701 cmp byte [bx + 1], dl ; if so, also check the next tile to the right 7e05 jle check_for_solid_ground in_ceiling: c60616cf08 mov byte [comic_y_vel], 8 ; bounce downward off the ceiling | | | | | check_for_solid_ground: 803e16cf00 cmp byte [comic_y_vel], 0 ; is the player moving downward? 7e1b jle not_on_solid_ground 8bce mov cx, si ; cl = comic_y_pos, ch = comic_x_pos 8bc1 mov ax, cx ; al = comic_y_pos, ah = comic_x_pos 0405 add al, 5 ; comic_y_pos + 5 e869f4 call lookup_tile_at_coordinates ; tile at player's feet (Comic is 4 units tall) 8a164007 mov dl, byte [last_solid_tile] 3817 cmp byte [bx], dl ; is it solid? 7f12 jg check_if_too_low f6c401 test ah, 1 ; is the player halfway between tiles? 7405 je not_on_solid_ground 385701 cmp byte [bx + 1], dl ; if so, also check the next tile to the right 7f08 jg check_if_too_low not_on_solid_ground: c6061acf04 mov byte [comic_graphic], 4 ; jumping graphic e9f7fd jmp return_to_game_loop check_if_too_low: 80f90f cmp cl, 0xf ; comic_y_pos < 7.5 tiles? 7202 jb on_solid_ground ; if so, tile check was meaningful ebf1 jmp not_on_solid_ground ; if not, player is too low for there to be ground on_solid_ground: fec1 inc cl 80e1fe and cl, 0xfe ; clamp player's feet to even tile offset 8bf1 mov si, cx ; player_y = (player_y + 1) & 0xfe c60613cf00 mov byte [comic_is_airborne], 0 c60616cf00 mov byte [comic_y_vel], 0 e9dcfd jmp return_to_game_loop

handle_falling_and_jumping: fe0e18cf dec byte [jump_counter] 740f je .L1 2e803e140001 cmp byte cs:[key_jump_state], 1 750b jne .L2 802e16cf07 sub byte [comic_y_vel], 7 ; still jumping upward eb09 jmp .L3 .L1: fe0618cf inc byte [jump_counter] ; jump_counter bottoms out at 1 .L2: c60617cf00 mov byte [in_ceiling_flag], 0 ; no longer in ceiling if jump is finished .L3: a016cf mov al, byte [comic_y_vel] 8ac8 mov cl, al d0f8 sar al, 1 d0f8 sar al, 1 d0f8 sar al, 1 8bde mov bx, si ; bl = comic_y_pos, bh = comic_x_pos 02d8 add bl, al ; bl = comic_y_pos + comic_y_vel/8 7d02 jge .L4 ; hit the top of the screen? b300 mov bl, 0 .L4: 021e17cf add bl, byte [in_ceiling_flag] c60617cf00 mov byte [in_ceiling_flag], 0 8bf3 mov si, bx ; comic_y_pos = max(0, comic_y_pos + comic_y_vel/8 + in_ceiling_flag) 80fb11 cmp bl, 0x11 ; comic_y_pos >= 8.5 tiles? 7203 jb .L5 e938ff jmp comic_dies ; die from falling in a pit .L5: 803e3e0002 cmp byte [current_level_number], 2 ; is this the space level? 7503 jne .L6 80e902 sub cl, 2 ; if so, comic_y_vel += 3 .L6: 80c105 add cl, 5 ; otherwise, comic_y_vel += 5 80f918 cmp cl, 0x18 ; comic_y_vel > 23? 7c02 jl .L7 b117 mov cl, 0x17 ; maximum falling velocity is 23 .L7: 880e16cf mov byte [comic_y_vel], cl 8a0e15cf mov cl, byte [comic_x_momentum] check_key_left: 2e803e160001 cmp byte cs:[key_left_state], 1 750e jne check_key_right c6061acf05 mov byte [comic_facing], 5 ; face left ; comic_x_momentum = max(comic_x_momentum - 1, -5) fec9 dec cl 80f9fb cmp cl, -5 7d02 jge check_key_right b1fb mov cl, -5 check_key_right: 2e803e170001 cmp byte cs:[key_right_state], 1 750e jne .L8 c6061acf00 mov byte [comic_facing], 0 ; face right ; comic_x_momentum = min(comic_x_momentum + 1, +5) fec1 inc cl 80f905 cmp cl, +5 7e02 jle .L8 b105 mov cl, +5 .L8: 880e15cf mov byte [comic_x_momentum], cl check_move_left: 0ac9 or cl, cl ; comic_x_momentum < 0? 7d07 jge check_move_right fe0615cf inc byte [comic_x_momentum] e88b00 call comic_moves_left a015cf mov al, byte [comic_x_momentum] check_move_right: 0ac0 or al, al ; comic_x_momentum > 0? 7e07 jle check_for_head_bonk fe0e15cf dec byte [comic_x_momentum] e8d900 call comic_moves_right check_for_head_bonk: 8bc6 mov ax, si ; al = comic_y_pos, ah = comic_x_pos e876f4 call lookup_tile_at_coordinates ; tile at player's head 8a164007 mov dl, byte [last_solid_tile] 3817 cmp byte [bx], dl ; is it solid? 7f0a jg in_ceiling f6c401 test ah, 1 ; is the player halfway between tiles? 7418 je check_for_solid_ground 385701 cmp byte [bx + 1], dl ; if so, also check the next tile to the right 7e13 jle check_for_solid_ground in_ceiling: | 803e16cf00 cmp byte [comic_y_vel], 0 ; is the player moving downward? 7f0c jg check_for_solid_ground c60617cf01 mov byte [in_ceiling_flag], 1 ; stick to the ceiling c60616cf00 mov byte [comic_y_vel], 0 ; but stop moving upward eb22 jmp not_on_solid_ground check_for_solid_ground: 803e16cf00 cmp byte [comic_y_vel], 0 ; is the player moving downward? 7e1b jle not_on_solid_ground 8bce mov cx, si ; cl = comic_y_pos, ch = comic_x_pos 8bc1 mov ax, cx ; al = comic_y_pos, ah = comic_x_pos 0405 add al, 5 ; comic_y_pos + 5 e841f4 call lookup_tile_at_coordinates ; tile at player's feet (Comic is 4 units tall) 8a164007 mov dl, byte [last_solid_tile] 3817 cmp byte [bx], dl ; is it solid? 7f12 jg check_if_too_low f6c401 test ah, 1 ; is the player halfway between tiles? 7405 je not_on_solid_ground 385701 cmp byte [bx + 1], dl ; if so, also check the next tile to the right 7f08 jg check_if_too_low not_on_solid_ground: c6061bcf04 mov byte [comic_graphic], 4 ; jumping graphic e9cffd jmp return_to_game_loop check_if_too_low: 80f90f cmp cl, 0xf ; comic_y_pos < 7.5 tiles? 7202 jb on_solid_ground ; if so, tile check was meaningful ebf1 jmp not_on_solid_ground ; if not, player is too low for there to be ground on_solid_ground: fec1 inc cl 80e1fe and cl, 0xfe ; clamp player's feet to even tile offset 8bf1 mov si, cx ; player_y = (player_y + 1) & 0xfe c60613cf00 mov byte [comic_is_airborne], 0 c60616cf00 mov byte [comic_y_vel], 0 e9b4fd jmp return_to_game_loop