Sega CD loading question

[cdoty]

I'm nearing the end of Frog Feast for the Sega CD.

I'm putting a few logo screens before the game. I split the logo screens into their own program, and am trying to load another program after that. It works in Gens and Fusion, but only loads the first part on the real system.

I transfer my loading code to 0xFF0000, and load the file into 0x20000, which is where the first part loads to.
I'm also using the exact same code as I do to load the first part. (The sub CPU code is cdread.asm from MOD).

Both parts are less than 64k (56k for the first and 31k for the second).

Wasn't there some discussion about loading a part that is smaller than the last loaded part?

Any ideas?

[cdoty]

Damn, the problem had nothing to do with the Sega CD. I was accessing the HV counter mirror ($C0000E) as a DWORD. The system was locking up after that most of the time. It did work on a few occasions.

I assume that accessing $C00008 as a DWORD would cause the same problem.

[Fonzie3]

The genesis vdp HV counter?

"The system was locking up"... A true lockup or just the INT that stops?

Cause, I have serious problems with segacd bios but it doesn't create a lockup (just don't do anything)...

Thx

Fonzie

[oompa loompa]

are you checking the HV counter inside the horizontal blank interrupt? the sega cd does different things to the horizontal interrupt that could lock up the machine if the jump register isn't set right

[cdoty]

No, I'm checking it before I start anything as a random number seed.

[oompa loompa]

reading the hv counter at the begining of the program shouldn't crash anything at all. i think it may be something else that's crashing it. the only thing that i could think of that could crash the genesis on sega cd is the horizontal interrupt