Well, simplest thing: if you have one programming error like game writing slightly out of allocated memory block, then you corrupt the system when returning to the OS.

with whdload it can't really happen because even games using the OS are virtualized through kickstart emulation, and some of your productions (Tiny Bobble, Tiny Galaga & Invaders and soon WrongWayDriver so I can play it :)) make a minimal use of the OS so I can trivially patch the calls.

Plus whdload protects memory blocks so nothing can be read or written outside them (exception: blitter going crazy and killing chipmem out of bounds, but that's rare). whdload also has a SNOOP option (with MMU) which checks that custom registers aren't accessed the wrong way (read of write-only register, not waiting for blitter to finish before starting new blit, invalid bits in bplcon...)

Disabling the caches on startup just because someone has a problem is pretty counter-productive. You know how to get/set the VBR and MMU TC so disabling CACR is also easy. Read, write zero, write old value on exit (some 1993-94 ECS 68020-aware games already do that). once again whdload has a NOCACHE option that does exactly that :)

Thanks for the information.
I'm aware of these possible issues but wondered if all of my games maybe trigger the same issue because of an oversight (because i re-use my startup/exit code)..

I know its hopeless to support every setup, but if there are common issues with say, 060's, then I would like to address them.
The first demo I put out uses DOS for file loading, but I've since moved to using a bootblock/trackdisk approach. Using DOS was appealing as the program ran from Workbench or floppy, but there was one problem I could not resolve. Turrican plays music during the loading phases. TFMX wants level 4 and 6 interrupts, plus audio DMA of course. So far I've been unable to find any combination of re-enabling the OS that both allowed both DOS loading to work and didn't disable or trash the interrupts needed for music.
It does make life easier ignoring the OS, but it makes me unhappy. :(

don't worry, a lot of "os compliant" games just ignore the OS when they run.

Did you use the OS when adding your ISRs, or did you modify the vectors directly?


https://wiki.amigaos.net/wiki/Exec_Interrupts

A solution would be to ditch any loading at all and unpack from RAM (when you target A1200+4MB Fast). The MSDOS version was around 2MB packed.
Tho it would be a nice challenge to fit the whole game into 2MB chip. May work when shrinkling the data and not using bitplanes for packing the data.. :)

No, I'm mixing system takeover with OS use, which know is a no-no and the source of my problems.

The newer version is system-takeover only. I would, in an ideal world, like to support both, but being practical it is not something I should aim for in the near future.

That's certainly a possibility.

I did so with TinyBobble and Tinyus which ran on 512chip+512kb. It didn't use shrinkler because its too slow on A500 but i used Doynax/Doynamite. Very fast and good lz compression. You find it here:
https://github.com/AxisOxy/Planet-Ro...s/doynamite68k

One space saving trick i used in 'Coda':
To get much better pack ratio with bitplane gfx you can pack the gfx as 8bit chunky and then do a chunk2planar after decrunching. It often gave me upto 30% better pack ratio. Longer TFMX samples could be packed to 4bit ADPCM if you really need it (they won't pack that good). I would not touch the small, quick looping ones.

Like other I mainly use WHDLoad these day but an interesting exception there is Batman The Movie works on the 060 but not the 030 weird!

Tiny Bubble works from floppy on both machine. Also, I've got The Ministry Zool AGA crack to work on the 060 but not the 030. Only the first level works with graphics glitches but the 030 just keeps asking for disk 1 when it's time to ask for disk 2! Funny incompatibilities between the Motorola CPUs me thinks?

For heavy hitting things like TFX I switch to Workbench 3.1 with Oxypatcher rather than OS3.9 BB2 but this is loading from floppy so the Workbench/AmigaOS version on the hard drive shouldn't matter!

If you use the Intel ADPCM reference encoder you would better if you add this step (because it was born mainly for 16-bit samples..):I simply applied the same principle used for 4 bit to 8 bit color component 'expansion': a better mapping for the values in the 16 bit spectrum.

In extreme cases of memory shortage I even applied a compression for the sample bringing 8 bits to 1 (but the result, even if intelligible, is not really the best :D)

What happens on 030? I didn't have any 030 machine at my disposal when I updated the patch some years ago. Also, it is better to report such problems in the Mantis bugtracker as chances are much higher that they will be noticed then.

The WHDLoad version doesn't even get to the intro screen after the WHDLoad window pops up it just does black screen I think on my 030.

That sounds like your 030 Amiga may run a TCP/IP stack or something similar. It needs to be disabled when running WHDLoad patches. Please check and if that is not the reason for the black screen, send me a PM and I'll have a look.

//end of off-topic and sorry to Muzza. :)

@Muzza

Nice job, thanx.

i have been dreaming of an aga conversion of the ms dos vga version since the 90s. thanks for that! but please don't bug the developer with an amiga cd/cd32 version with cd audio... let him first finish the project as he sees fit! Of course an optional CD audio track would be cool, you can take a cue from the soon to be released Turrican Anthology, but like i said, let him finish the project first. The Turrican Anthology should be out sometime this year for the current consoles.

I just had a quick go, the colors are great, the features are there. Excellent work

(please change the main character sprite to the amiga version :))

NO!:nuts ;)

Tested on two A4000's in PAL mode. One has GVP 4060 and the other A3660. Doesn't run, locks up at grey screen.

Oh, if you can solder, i still have some ADD4MB kits for sale i think...just send me a PM if intrested.



Btw. great work with Turrican AGA, are you the same person working on the Mega65 version :)