If you hit jump key, you won't be able to play game.
1. Go to 'cheat code' menu
2. Enter DDDD, and press Space-bar.
3. Press '1' and you can play prehistoric 2.
OMG it works!
but how?
heh
you just have to enter a cheat menu, you don't have to type anything there
i have just recalled that i have used this method half a year ago and i even finished the game (with help of gamewizard 😉 ).
i just wasn't sure whether it was dosbox or not but i recall that it had to be dosbox cause i was slowing the game down on final levels, and i have never used any slowdown proggies 😉
btw- with gamewiz32 i have managed to use glider on every level 😉
wrote:OMG it works!
but how?
This is a nice way around the "anti-debugger" protection of Prehistorik 2.. 😀
To get rid of debuggers, the game sets the INT3-vector to a memory location between F000:0000 and F000:FFFF. This is a ROM section in real memory and therefor cannot be changed by a debugger to implement breakpoints.
However, the game is paranoid and checks if this memory area is really read-only whenever you pick an option in the main menu. Unfortunally, the area is NOT read-only in DOSBOX, so the game destroys a vital function.
But the "destroy function" is designed in a way that it will actually repair the function if applied a second time. So:
Odd number of main menu selections = Function broken
Even number = Function okay
