Comment by phire

Worse, that would mean Arm64 is a 12-bit CPU. The original 32-bit ARM encoding could only load 8 bit immediates, though later versions gained a 16-bit load immediate instruction.

RISC-V is a bit better off, as it has a special encoding for 20 bit immediates, while Alpha and PowerPC are the same as MIPS, stuck with 16-bit immediates.