eee, my Uxn implementation passes the opcode tests!

the main bugs i had to squash were misunderstanding byte order on the stack (since it's big endian, you pop the low byte first), decrementing the stack pointer after popping instead of before, and wrangling the SFT specification vs Zig's expectations about bitshifting.

#uxn #zig #theWorkshop

github.com/ryleelyman/uxn-zig