Hidden music in "Teenage Mutant Hero Turtles : The Coin Op" & "Shadow Dancer" ?

[kawickboy]

Tunes are now on CPC-POWER too for a long time. Did someone try to patch the game (128ko probably) ?

Did someone find the hidden Shadow Dancer tunes ?

[Jean-Marie]

This can be challenging. Those games disable entirely the interrupts so they can use the stack to display the sprites more quickly (Interrupts use the stack and would mess up the sprites).
Still, we need the interrupts to be enabled, because the music player must be called in a timely fashion.
Basically, you need to :
* enable interrupts entirely
* locate the sprites display functions
* "insert" a DI instruction (disable int.) before the function use the stack to draw the sprite
* "insert" a EI instruction (enable int.) when the function is finished

With Sly Spy, there was only 3 short functions to modify, and luckily I was able to optimize them for size, so I could insert the DI & EI instructions. That was clean and straightforwad.
But sometimes, it can be more difficult. I'll have a closer look anyway...

[Jean-Marie]

Well, It was challenging, as I expected. I won't do that every day 

[Jean-Marie]

New version: You can now switch between Music & SFX ingame !
Press the P key to pause the game, then S.

[viddi]

WOW! Thank you. What a great achievement. 

[kawickboy]

Champagne. Can't wait to load this release. Thanks.