The Intersil 80C286/883 is a static CMOS version of the
NMOS 80286 microprocessor. The 80C286/883 is an
advanced, high-performance microprocessor with specially
optimized capabilities for multiple user and multi-tasking systems.
The 80C286/883 has built-in memory protection that
supports operating system and task isolation as well as program
and data privacy within tasks. The 80C286/883
includes memory management capabilities that map 230
(one gigabyte) of virtual address space per task into 224
bytes (16 megabytes) of physical memory.
The 80C286/883 is upwardly compatible with 80C86 and
80C88 software (the 80C286/883 instruction set is a superset
of the 80C86/80C88 instruction set). Using the 80C286/
883 real address mode, the 80C286/883 is object code compatible
with existing 80C86 and 80C88 software. In protected
virtual address mode, the 80C286/883 is source code
compatible with 80C86 and 80C88 software but may require
upgrading to use virtual address as supported by the
80C286/883’s integrated memory management and protection
mechanism. Both modes operate at full 80C286/883
performance and execute a superset of the 80C86 and
80C88 instructions.
The 80C286/883 provides special operations to support the
efficient implementation and execution of operating systems.
For example, one instruction can end execution of one task,
save its state, switch to a new task, load its state, and start
execution of the new task. The segment-not-present exception
and restartable instructions.