user manual

22007E/0—November 1999 AMD Athlon™ Processor x86 Code Optimization
Introduction 129
Appendix A
AMD Athlon™ Processor
Microarchitecture
Introduction
When discussing processor design, it is important to understand
the following terms—architecture, microarchitecture, and design
implementation. The term architecture refers to the instruction
set and features of a processor that are visible to software
programs running on the processor. The architecture
determines what software the processor can run. The
architecture of the AMD Athlon processor is the
industry-standard x86 instruction set.
The term microarchitecture refers to the design techniques used
in the processor to reach the target cost, performance, and
functionality goals. The AMD Athlon processor
microarchitecture is a decoupled decode/execution design
approach. In other words, the decoders essentially operate
independent of the execution units, and the execution core uses
a small number of instructions and simplified circuit design for
fast single-cycle execution and fast operating frequencies.
The term design implementation refers to the actual logic and
circuit designs from which the processor is created according to
the microarchitecture specifications.