Apparently you can `mov r0, r1` in thumb without setting status

[velipso]

Word on discord is you can perform a mov in thumb on low registers without setting status. They claim it's undocumented.

I should verify this on real hardware and, assuming it's true, implement it in gvasm somehow.

Gericom: The mov opcode for hi registers (which doesn't update flags) works just fine for low registers on arm7tdmi, but since that's not officially defined behavior it won't be used in the compiler

should use cpy mnemonic