Editing Intel 80186 (section)

== Description ==
[[File:Intel 80186 80188 arch.svg|upright=1.4|thumb|A greatly simplified block diagram of the 80186 architecture]]
[[File:Intel 80186 die.JPG|thumb|[[Die (integrated circuit)|Die]] of Intel 80186]]

The 80186 series was designed to reduce the number of [[integrated circuits]] required. It included features such as [[clock generator]], [[interrupt controller]], [[hardware timer|timers]], [[wait state]] generator, [[direct memory access|DMA]] channels, and external [[chip select]] lines. It was used in numerous [[embedded system]]s, as [[microcontroller]]s with external memory.

The initial clock rate of the 80186 was 6&nbsp;[[MHz]], but due to more hardware available for the [[microcode]] to use, especially for address calculation, many individual instructions completed in fewer clock cycles than on an 8086 at the same clock frequency. For instance, the common ''register+immediate'' [[addressing mode]] was significantly faster than on the 8086,{{efn|In fact, all variants, including ''reg+reg'' and ''reg+reg+immediate'' were faster.}} especially when a memory location was both (one of) the operand(s) and the destination. Multiply and divide also showed great improvement, being several times as fast as on the original 8086, and multi-bit shifts were done almost four times as quickly as in the 8086.

A few new instructions were introduced with the 80186 (referred to as the 8086-2 instruction set in some [[datasheet]]s{{citation needed|date=July 2023}}): ''enter''/''leave'' (replacing several instructions when handling stack frames), ''pusha''/''popa'' (push/pop all general registers), ''bound'' (check array index against bounds), and ''ins''/''outs'' (input/output of string). A useful ''immediate'' mode was added for the ''push'', ''imul'', and multi-bit shift instructions. These instructions were also included in the contemporary 80286 and in successor chips.{{efn|The instruction set of the 80286 is a superset of the 80186's, plus new instructions for [[protected mode]].}}