Crash when doing a lot of fetching in ZScript

[Accensus]

Versions: GZDoom 3.1.0 and GZDoom g3.2pre-119-gac811f9
Both are x64.

What I have attached below is a HUD, but it has no graphics. Everything has been stripped to pinpoint the issue. Keep in mind that due to the nature of the error I had to make a lot of CVARs! (135 to be precise. No more, no less.) I suggest to backup your ini or burn it afterwards.

So, onto the point. What happens is that whenever I'd run the game, it'd crash. However, if you open up ZScript.txt and comment out any line in void UpdateKills(), there will be no crash on start-up. What I did may be a clear case of "Don't do that!", in which case I'd love to hear a suggestion on how to update variables. It's only a mere guess that adding some sort of a delay between calls to UpdateKills() and doing checks periodically would be a better idea, but I haven't tried that yet.

EDIT: Attached CrashReport, for what it's worth.

[Graf Zahl]

The crash occurs when the function accumulates more than 255 integer constants. I guess that the opcode to read a constant isn't working properly.

[Graf Zahl]

Fixed. The check for handling this was wrong for one particular opcode that got used here.

[Accensus]

Amazing. Thank you!

Is there an actual limit of how many variables one can have? And would 170 assignment operations almost each tic lag out?

[Graf Zahl]

Assignment operations are cheap. The biggest time waster in your code would be the (native) lookup of the actual CVARs and not the VM code.
Regarding limits. The available resources per function are:

- 32767 integer constants
- 32767 string constants
- 32767 float constants
- 32767 address constants (this includes all function addresses, RNGs or other native resources being referenced.)
- 256 integer registers
- 256 floating point registers
- 256 string registers
- 256 address registers
Note that registers and local variables are not equivalent. Some registers are needed for intermediate results and arrays and structs are allocated on the stack, not in registers.

[Accensus]

This is very useful to know. Thank you once again.

[Major Cooke]

I've made a dedicated page to ensure this information isn't lost.

However, by native resources, is that just functions or are properties included?

[Graf Zahl]

That's local resources per function. Classes are stored elsewhere in memory and are not affected by this.

[Matt]

Are these limits for every named or anonymous function being called?

Like, if I have a A_ABC() inside which there's a A_XYZ() call, do each of them have their own limit (i.e., I can have up to 256 address registers in A_XYZ without using up A_ABC's limit)

Also, is an "address register" like a pointer?

[Graf Zahl]

Each function gets its own set of registers. And yes, an address register is effectively a pointer.