The CDP1855 and CDP1855C are CMOS 8-bit multiply/divide units which can be used to greatly increase the capabilities of 8-bit microprocessors. They perform multiply and divide operations on unsigned, binary operators. In general, microprocessors do not contain multiply or divide instructions and even efficiently coded multiply or divide subroutines require considerable memory and execution time. These multiply/divide units directly interface to the CDP1800-series microprocessors via the N-lines and can easily be configured to fit in either the memory or I/O space of other 8-bit microprocessors.