Intel 80386SX CPU

Ref: Intel 386SX Microprocessor "Advance Information"

The 386SX microprocessor is a 32-bit CPU with a 16-bit extrenal data bus and a
24-bit external address bus.  The 386SX CPU brings the high performance
software of the Intel386 architecture to midrange systems.  It provides the
performance benefits of a 32-bit programming architecture with the cost savings
associated with 16-bit hardware systems.

The 386SX microprocessor is 100% objcet code compatible with the 386, 286 and
8086 microprocessors.  System manufacturers can provide 386 CPU based systems
optimized for performance and 386SX CPU based systems optimized for cost, both
sharing the same operating systems and application software.  Systems based on
the 386SX CPU can access the world's ;argest existing microcomputer software
base, including the growing 32-bit software base.  Only the Intel386
architecture can run UNIX, OS/2 and MS- DOS. DX/SX Differences

Instruction pipelining, high bus bandwidth, and a very high performance ALU
ensure short average instruction execution times and high system throughput.
The 386SX processor is capable of execution at sustained rates of 2.5 - 3.0
million instructions per second.

The integrated memory management unit (MMU) includes an address translation
cache, advanced multi-tasking hardware, and a four-level hardware-enforced
protection mechanism to support opearting systems.  The virtual machine
capability of the 386SX CPU allows simultaneous execution of applications from
multiple operating systems such as MS-DOS and UNIX.

The 386SX processor offers on-chip testability and debugging features. Four
breakpoint registers allow conditional or unconditional breakpoint traps on
code execution or data accesses for powerful debugging of even ROM-based
systems.  Other testability features include self-test, tri- state of output
buffers, and direct access to the page translation cache.





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