Hi, I don't have my code to hand right now but what I've done is break that up into 2 * 8 loops so only 3 rotates are required in each loop and I've got rid of the increment as the carry is carried back to the start of the loop.
So I've got 2 loops like this:

.loop ROL v+1
LDA v2
ROL A
ROL v3
CLC ...

Hi barrym and Gordon, thanks, I'll look through that.

Gordon, I'll be doing that when it comes to signed division, the negating at the start is so I have a positive and negative divisor value either of which is used for the addition depending on the previous pass through the loop.

There's something weird going on with this, I'll try to sort it out.

I'm looking at ways to divide and come up with this, it's unsigned 16/16=16 bits and doesn't give a remainder. Not fully tested so maybe some errors somewhere but it seems to work so far. I tried this after reading a comment about non restoring division changing the sign of the divisor. Is this any ...

This relies on V being clear and Y is clobbered so maybe not so good when it comes to debugging.
I think it's 7.5 or 8.5 depending on zp or not.

Very cool thanks. Are there any articles on how they're done?
I wasn't thinking of texturing, only solid or checked pixels. A big difference though would be that walls could be positioned anywhere at angles and any length.

I'll have a look, any links or what to search for? Any that would have run on original electron or BBC hardware?

Hi all, first off I'll say I realise this is a big ask so I don't know if anyone will be interested, particularly as I don't know how well this could really work or if anyone here would really be interested in attempting such a thing.

My first computer was an electron when I was about 10 and I got ...