Draw Bugs

[josefnpat]

From CodeInLabs:

https://itch.io/post/1349548

Some instructions don't work as expected. 

Draw, for instance:

R6 and R7 must be set to 3 and 14 (instead of 3 and 15) to draw at the rightmost pixel. 
If TargetX > 63, TargetY changes.

[josefnpat]

I think it's related to an issue on github, but just to be sure : In the draw op, does SourceX[R0+R1] means it will use r0 and r1 as a 8bit number ? (to be able to get up to 64 as a x position ?) so if I have r0 = 0001 and r1 = 0001 it will be 16 + 1 = 17 ? (looked at your lua code and it seems that way)