; Aysalia DOS Launcher
; Launches aydos1.gam and aydos2.gam
; Revision 2018-12-06
; (C) 2018 Daniel Marschall, ViaThinkSoft
.model small
.stack 10h
; -------------------------------------------------------
.data
exename1 db "AYDOS1.GAM",0
exename2 db "AYDOS2.GAM",0
cmdargs db 0,'',0dh
dummy_fcb db 36 dup(0)
paramblk dw 0 ; use environment of parent
dw cmdargs ; command line arguments
dw 0 ; cmdargs_seg
dw dummy_fcb ; fcb1
dw 0 ; fcb1_seg
dw dummy_fcb ; fcb2
dw 0 ; fcb2_seg
menu1 db '', 13, 10, '$'
menu2 db '', 13, 10, '$'
menu3 db '', 13, 10, '$'
menu4 db '', 13, 10, '$'
menu5 db ' Aysalia DOS',13,10,'$'
menu6 db '', 13, 10, '$'
menu7 db '', 13, 10, '$'
menu8 db ' Welches Spiel soll gestartet werden?',13,10,'$'
menu9 db '', 13, 10, '$'
menu10 db ' Dr',81h,'cke eine der folgenden Tasten:',13,10,'$'
menu11 db '', 13, 10, '$'
menu12 db ' 1 Aysalia DOS I',13,10,'$'
menu13 db ' 2 Aysalia DOS II',13,10,'$'
menu14 db '', 13, 10, '$'
menu15 db ' 9 Beenden',13,10,'$'
menu16 db '', 13, 10, '$'
menu17 db '', 13, 10, '$'
menu18 db '', 13, 10, '$'
error1 db '',13,10,'$'
error2 db 'Fehler: Spiel kann nicht gestartet werden. Fehlt eine Datei?',13,10,'$'
error3 db '',13,10,'$'
gameover1 db '',13,10,'$'
gameover2 db 'Spiel zu Ende!',13,10,'$'
gameover3 db '',13,10,'$'
; -------------------------------------------------------
.code
clear_vga PROC
mov ax, 0a000h
mov es, ax
xor di, di
mov ax, 0
mov cx, 64000
rep stosb
ret
clear_vga ENDP
set_screen12 PROC
mov ah, 0 ; set screen mode
mov al, 12h ; graphic mode, 640x480 pixel, 16 colors (VGA)
int 10h
ret
set_screen12 ENDP
setup_paramblk PROC
mov ax, cs
mov [paramblk + 4], ax ; cmdargs_seg
mov [paramblk + 8], ax ; fcb1_seg
mov [paramblk + 12], ax ; fcb2_seg
ret
setup_paramblk ENDP
set_numlock_on PROC
push ds
mov ax, 40h
mov ds, ax ; go to BIOS Data Area ( http://stanislavs.org/helppc/bios_data_area.html )
mov bx, 17h ; Load Keyboard flag byte 0
mov al, [bx] ; read
or al, 20h ; set bit 5 (numlock) to 1
mov [bx], al ; write
pop ds
ret
set_numlock_on ENDP
flush_keyb_buf PROC
mov ah, 0Ch ; Flush input buffer and input
mov al, 0
int 21h
ret
flush_keyb_buf ENDP
exit_to_dos PROC
mov ah, 4ch
mov al, 00h
int 21h
ret
exit_to_dos ENDP
sleep_5 PROC
mov ah, 00h
int 1Ah
cmp dx, 7FFFh
jg upperhalf
lowerhalf:
mov bx, dx
add bx, 91 ; 18.2 = 1 sec (therefore 91 = 5 sec)
lowerhalf_again:
int 1Ah
cmp dx, bx
jl lowerhalf_again
ret
upperhalf:
mov bx, dx
sub bx, 7FFFh
add bx, 91 ; 18.2 = 1 sec (therefore 91 = 5 sec)
upperhalf_again:
int 1Ah
sub dx, 7FFFh
cmp dx, bx
jl upperhalf_again
ret
sleep_5 ENDP
print_menu_screen PROC
mov ah, 0Bh
mov bh, 00h
mov bl, 8 ; green
int 10h
mov ah, 9
lea dx, menu1
int 21h
lea dx, menu2
int 21h
lea dx, menu3
int 21h
lea dx, menu4
int 21h
lea dx, menu5
int 21h
lea dx, menu6
int 21h
lea dx, menu7
int 21h
lea dx, menu8
int 21h
lea dx, menu9
int 21h
lea dx, menu10
int 21h
lea dx, menu11
int 21h
lea dx, menu12
int 21h
lea dx, menu13
int 21h
lea dx, menu14
int 21h
lea dx, menu15
int 21h
lea dx, menu16
int 21h
lea dx, menu17
int 21h
lea dx, menu18
int 21h
ret
print_menu_screen ENDP
print_error_screen PROC
mov ah, 0Bh
mov bh, 00h
mov bl, 4 ; red
int 10h
mov ah, 9
lea dx, error1
int 21h
lea dx, error2
int 21h
lea dx, error3
int 21h
ret
print_error_screen ENDP
print_gameover_screen PROC
mov ah, 0Bh
mov bh, 00h
mov bl, 4 ; red
int 10h
mov ah, 9
lea dx, gameover1
int 21h
lea dx, gameover2
int 21h
lea dx, gameover3
int 21h
ret
print_gameover_screen ENDP
; -------------------------------------------------------
start:
; Setup data segment
mov ax, @data ; moving base address of data to ax
mov ds, ax ; moving contents of ax into ds
; data section now gets initialized
; Preserve the original screen mode
mov ah, 0Fh ; Query screen mode
int 10h
push ax ; actually, we are only interested in register al (screen mode), not in ah (column count)
; Change numlock to ON
; DOSBox has a bug where the NumLock is not correctly set to the setting of the host system,
; so you have to press the NumLock key twice so that DOSBox recognizes the status.
; see: https://sourceforge.net/p/dosbox/bugs/71/
; https://superuser.com/questions/255102/is-there-a-way-to-use-the-numeric-keypad-in-dosbox/1146986
; Since the game uses number keys very often, we set NumLock to ON
call set_numlock_on
; Reduce size of own application to give the called applications more space
; see https://stackoverflow.com/a/10067627
mov ah, 4Ah
mov bx, 100 ; 100 paragraphs a 16 bytes = 1600 bytes
int 21h
menu:
; Video Mode VGA 12
call set_screen12
; Flush keyboard buffer
call flush_keyb_buf
; Print menu screen
call print_menu_screen
retry:
; Query keyboard input
mov ah, 07h ; Direct character input, without echo
int 21h
cmp al, '1'
je prog1
cmp al, '2'
je prog2
cmp al, '9'
je exit
; Invalid input
jmp retry
prog1:
; Clear screen
call clear_vga
; Setup parameter block for the EXEC command
call setup_paramblk
; Start game 1
mov ah, 4Bh ; execute
mov al, 00h ; load and execute
mov bx, paramblk
lea dx, exename1
int 21h
; Is everything OK? Or is the GAM file missing?
jc error
; Notify the player that the game has finished
jmp gameover
prog2:
; Clear screen
call clear_vga
; Setup parameter block for the EXEC command
call setup_paramblk
; Start game 2
mov ah, 4Bh ; execute
mov al, 00h ; load and execute
mov bx, paramblk
lea dx, exename2
int 21h
; Is everything OK? Or is the GAM file missing?
jc error
; Notify the player that the game has finished
jmp gameover
error:
; Video Mode VGA 12
call set_screen12
; Clear screen
; call clear_vga
; Print error
call print_error_screen
; Give the player time to read the error message (approx 5 seconds)
call sleep_5
; Go back to the menu
jmp menu
gameover:
; Print gameover screen
call print_gameover_screen
; Give the player time to read the game over message (approx 5 seconds)
call sleep_5
; Go back to the menu
jmp menu
exit:
; Reset video mode to DOS default
pop ax ; the video mode we have preserved at program start
mov ah, 0 ; set screen mode
int 10h
; Return to DOS
call exit_to_dos
; -------------------------------------------------------
end start