@QuanTech also I found another bug: when you press compile, the command is always HALT, because the FILT that ORs the right command to the instruction gets deleted right before the bray gets ORed with it. Also: can you DM me on the Powdertoy chat so we can talk about fixing the compiler there?

I wrote some code that emulates the C4C 1 execution as a virtual machine. The code can be found here:

https://pastebin.com/7X1KamHs