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This book details the specifications, microarchitecture, VHDL implementation and evaluation of a SPARC v8 CPU with fine-grain multithreading, also known as ´micro-threading´. This alternative CPU, named UTLEON3, is compatible with the standard GRLIB package.

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This book describes a specification, microarchitecture, VHDL implementation and evaluation of a SPARC v8 CPU with fine-grain multi-threading, called micro-threading. The CPU, named UTLEON3, is an alternative platform for exploring CPU multi-threading that is compatible with the industry-standard GRLIB package. The processor microarchitecture was designed to map in an efficient way the data-flow scheme on a classical von Neumann pipelined processing used in common processors, while retaining full binary compatibility with existing legacy programs.

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Introduction.- The LEON3 Processor.- Microthreaded Extensions.- The Basic UTLEON3 Architecture.- UTLEON3 Programming by Example.- UTLEON3 Implementation Details.- Execution Effieciency of the Microthread Pipeline.- Hardware Families of Threads.- I/O and Interrupt Handling in the Microthread Mode.- The IU3 Pipeline.- Excerpts from the LEON3 Instruction Set.- Relevant LEON3 Registers and Address Space Identifiers.- Scheduler Example.- Used Resources.- Tutorial.

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