Apparently CP only works for the accumulator, but I need to compare IY with 0 without destroying it.
Is there are fast method for this? I was planning on using it for a sprite drawing function, if that helps.

Why not just use the super optimized sprite routines in the C libraries please? (graphx)

This works, but sets bc (or another reg) and hl to iy.


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Only set hl to iy:


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Both are the same size.

I tried finding a sprite routine but all that I found relied on huge libs I had to import or add to my calculator, or used the graph buffer, something which I can't find documentation on anywhere.

I just want something that pastes into the vRam, which I didn't find.

What are you talking about; the source for the libraries is freely available. Just use the routine you need. You clearly don't understand how libraries work on the CE, but whatever.

https://github.com/CE-Programming/toolchain/blob/master/src/graphx/graphx.asm#L2312

Sometimes, a better way to check if iy is equal to 0 can be to do
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which sets the carry flag if iy is not zero. Of course the main issue with this is that it destroys iy and having to do inc iy to restore it causes it to lose its advantage over the other methods, unless multiple values need to be compared equal to zero at the same time in which case they can share the value already loaded into bc or de.

And I must go through a horde of source files just to find something I need instead of just one simple function being available standalone? That's just horrible.

Mateo did link directly to the sprite routine so you don't have to scour through the entire document, which is handy.

However if you manage to find the time I do suggest you take a look at the various routines in that file, there is a lot of useful code within!

One thing to note is that the C toolchain sprite routines expect the LCD to be at a specific bitdepth (8bpp). I'm not sure what your project will utilise so there may be some minor modification required if it differs from this. The linked routine also has no clipping, though there are clipped versions in the file too!

I'll just copy / paste it here with a few modifications. Hope this helps


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