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

References for Code Changes

R3 Esc

Revision 2 @ 76	Revision 3 @ 76
cd16 int 0x16 ; get keystroke; al=ASCII code 3c6b cmp al, 0x6b ; 'k' 7407 je setup_keyboard 3c4b cmp al, 0x4b ; 'K' 7403 je setup_keyboard e95001 jmp game_start	cd16 int 0x16 ; get keystroke; al=ASCII code 3c6b cmp al, 0x6b ; 'k' 740e je setup_keyboard 3c4b cmp al, 0x4b ; 'K' 740a je setup_keyboard 3c1b cmp al, 0x1b ; Esc 7503 jne any_other_key e95203 jmp terminate_program any_other_key: e95401 jmp game_start

R3 Del

Revision 2 @ 1b6	Revision 3 @ 1a0
await_keypress: ; [...] ; bx is scancode 4b dec bx ; scancode == 0x1 (Esc)? 74c5 je await_keypress 83fb51 cmp bx, 0x51 ; scancode > 0x52 (Ins)? 7fc0 jg await_keypress ; assign scancode to action	await_keypress: ; [...] ; bx is scancode 4b dec bx 74d1 je await_keypress ; scancode == 0x1 (Esc)? 83fb52 cmp bx, 0x52 7fcc jg await_keypress ; scancode > 0x53 (Del)? ; assign scancode to action

R3 Keyboard Buffer

Revision 2 @ 2b4	Revision 3 @ 1d1
; 0040:1a is pointer to beginning of the buffer of pending keystrokes ; 0040:1c is pointer to end 268a0e1a04 mov cl, byte es:[0x41a] 26880e1c04 mov byte es:[0x41c], cl ; set end = beginning	; 0040:1a is pointer to beginning of the buffer of pending keystrokes ; 0040:1c is pointer to end fa cli ; disable interrupts 268a0e1a04 mov cl, byte es:[0x41a] 26880e1c04 mov byte es:[0x41c], cl ; set end = beginning fb sti ; enable interrupts