16-bit and multiple byte arithmetic

Abstract

So far we have been concerned with 8-bit arithmetic — that is, 8-bit operands and 8-bit results. The range of numeric values which can be manipulated by 8-bit arithmetics is small and so we may need to use 16-bit arithmetic and more. The Z80 microprocessor has instructions which allows 16-bit arithmetic to be performed directly. These instructions can also be used to provide 32-bit arithmetic, 48-bit arithmetic and so on. The 16-bit arithmetic instructions also allow additional loop facilities.