Jetpac fixed

Managed to fix the strange behavour in Jetpac where the only bonus falling from the top of the screen was gold bars. The problem was staring me in the face… literally.

The R register is commonly used as a random number generator. My calculation of the register had a bug which reset it to 0 after each instruction. I’m not sure why I didn’t spot it sooner, considering it is displayed on the debug screen!

I have also looked into the Chuckie Egg crash problem. It looks like there is a problem with the mode 2 interrupt handling. When an interrupt fires it seems to be executing the wrong section of memory and causes a crash…

Advertisements

No comments yet

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: