Running another program question

[Welshworrier]

I've spent a good few days now trying to get some software working that will take a coff file and start it running.

 

All files I've tried work.... Except one

 

Gem Racer by Dr Typo just refuses to work correctly. I get it moved to the correct location (4000), make sure the SR is set, DSP and GPU doing nothing, blitter clear, vbl etc... What happens is the game starts but when you hit a key to choose level it displays the screen BUT the road is not there, the car is, and the game itself will not play. Music still works.

 

It must be something I've not set correctly but I'm at a loss as to what to try next.

 

Anyone got any suggestions to effectively soft reset.

 

Should add this is on the jaguar itself

Edited October 26, 2017 by Welshworrier

[Zerosquare]

It may be a latent bug in Gem Racer that makes it sensitive to something that shouldn't matter. Try clearing the unused RAM areas to different values, same with 68k registers.

[Welshworrier]

Looking like it, spent a while disassembling it today to look. It works if put to a skunk board, with the usual jiffi header that sets sr and copies it down but just hates my code it's the only one he didn't release the source code for it seems - makes it more interesting though.

 

However the number of times I've heard the title music is starting to grate

 

Already tried clearing unused ram and looking at the code it doesn't seem to do anything really suspect - the display looks like it's blitted into double buffered area so that's where I'm currently checking to ensure all those registers are happy.

Edited October 27, 2017 by Welshworrier

[Welshworrier]

And here's a video of what I mean:

Edited October 27, 2017 by Welshworrier

[Welshworrier]

Update: got it working

Very subtle bug in that when it installed the DSP routines it didn't initialise the variables before hand. This meant on the first run through it checked for 0 in local dsp memory and, because I'd not cleared it all prior to calling it, thought the interrupt handler was already installed.

 

Solution was to ensure the local DSP memory was cleared before jumping to the start.

 

Now all the stuff I've tested works

Edited October 27, 2017 by Welshworrier