Microprocessor using an instruction field to specify expanded functionality and a computer system employing same

摘要

A microprocessor is provided which expands the functionality and/or performance of the implemented architecture in transparent and/or non-transparent ways. The microprocessor is configured to detect the presence of segment override prefixes in instruction code sequences being executed in flat memory mode and to use the prefix value to control internal and/or external functions. Additionally, the microprocessor may be configured to signal a change or modification of the normal execution of the instruction(s) which follow. Many embodiments are shown which use the segment override prefixes to expand the performance or capability of the microprocessor. Backward compatibility with older implementations of the x86 architecture may be maintained when implementing transparent embodiments.