With a dedicated zero register it's possible to implement some useful instructions as assembler pseudoinstructions and not on the CPU itself, saving chip area.

With a dedicated zero register it's possible to implement some useful instructions as assembler pseudoinstructions and not on the CPU itself, saving chip area. For example, the original MIPS instruction set has these pseudoinstructions: - li $d, imm (load immediate) is replaced with ori $d, $0, imm (or immediate with the zero register) - not $d, $s (bitwise complement) is replaced with nor $d, $0, $s (bitwise NOR with the zero register) ... and some others as well.