Page 1 of 1
Fixing Star Defence
Posted: Thu May 26, 2016 6:34 am
by GreyGhost
Does anyone know of a working version of this game? The copy I have and the one in Gamebase stores values at $a000 and $a001 and then falls into an endless loop at $1a2e. I'm sure this is some sort of copy protection but I can't seem to follow the code to see a work around.
Code: Select all
.C:1a1c FF FE FF ISB $FFFE,X
.C:1a1f FF A9 08 ISB $08A9,X
.C:1a22 8D 0F 90 STA $900F
.C:1a25 20 AD 1E JSR $1EAD
.C:1a28 20 9A 1C JSR $1C9A
.C:1a2b 20 2D 1D JSR $1D2D
.C:1a2e 4C 2E 1A JMP $1A2E
.C:1a31 A9 20 LDA #$20
.C:1a33 8D 00 A0 STA $A000
.C:1a36 A9 1A LDA #$1A
.C:1a38 8D 01 A0 STA $A001
.C:1a3b 4C 20 1A JMP $1A20
Re: Fixing Star Defence
Posted: Thu May 26, 2016 6:48 am
by mrr19121970
I don't know this game, but why don't you set the memory to read only ? K3ys expander has this to bypass such protection
Re: Fixing Star Defence
Posted: Thu May 26, 2016 8:48 am
by Mike
Have you tried pressing [f1] to start the game?
Actually, there's nothing dubious about the code. The game just thwarts soft-loaded (monitor?) cartridges by redirecting the reset vector of their auto-boot signature to its own init code. This init code sets up an interrupt
for the whole game main loop, which first waits for [f1] and then runs the game. The foreground process then idles in $1a2e.
So, nothing's to fix here.
P.S. the game is effectively PAL only as it uses an overscan screen that wouldn't fit on NTSC.
Re: Fixing Star Defence
Posted: Thu May 26, 2016 10:44 am
by GreyGhost
Mike wrote:Have you tried pressing [f1] to start the game?
*face palm* No, didn't try that one. Thanks Guys.
Re: Fixing Star Defence
Posted: Fri May 27, 2016 10:08 am
by paradroid90
Great Game though
Re: Fixing Star Defence
Posted: Sat Feb 09, 2019 3:05 am
by Vic20-Ian
Old Thread but if you try this game be sure to try the 2 game modes.
Function keys control 1 or 2 player and slow or fast game
From memory I think F5 toggles the game speed - it plays a tone but does not say slow of fast mode on screen.
High speed is frenetic. Good Scrolling and lovely laser effects.
A great version of Stargate / Defender.
Save 4 people and go through the stargate to warp to higher levels.
Destroy all the humans to blow up the planet until you survive 4 waves of mutants.
Smart bomb on Return and Invisible mode on Shift. Hyperspace (often kills you) on Spacebar and Radar on F3
Re: Fixing Star Defence
Posted: Sun Feb 10, 2019 6:04 pm
by hasseapa
As far as I remember this is the most playable Defender clone for Vic. I am partial to Jeff Minter's Defenda (aka Agressor) as I got it for Christmas, but Star Defence is better. I especially like the scaling of the small player ship and the big enemies (the opposite of Defenda) and as you say, the explosions are very satisfying.
The ground/mountains could look better and smoother scrolling would obviously also be an improvement.
Re: Fixing Star Defence
Posted: Mon Feb 11, 2019 2:27 am
by Vic20-Ian
I think it scrolls pretty good especially on fast mode.
I would like a life poke / trainer for this game to explore the levels.
Yllabian Dogfight is wave 5 - just white spaceships.
Firebomber Showdown - empty wave ?! on wave 10.
I never got to Wave 15...Wonder who shows up ?
Re: Fixing Star Defence
Posted: Mon Feb 11, 2019 4:38 pm
by hasseapa
It's been ages since I played it but it does sound very attractive from your description of the levels. I will fire it up on emulator when I have the time - hopefully soon.
Re: Fixing Star Defence
Posted: Sun Nov 29, 2020 4:25 pm
by Vic20-Ian
hasseapa wrote: ↑Mon Feb 11, 2019 4:38 pm
It's been ages since I played it but it does sound very attractive from your description of the levels. I will fire it up on emulator when I have the time - hopefully soon.
There is a trained version now and you can see extra levels named every 5 waves.