The SPARC Architecture Manual - SPARC International, Inc.!

Although different SPARC-V9 systems may execute nonprivileged programs at different rates,they will generate the same results, as long as they are run under the same memory model. SeeChapter 8, “Memory Models,” for more information.Additionally, SPARC-V9 is designed to be binary upward-compatible from SPARC-V8 for applicationsrunning in nonprivileged mode that conform to the SPARC-V8 ABI.1.2.5 Architectural DefinitionThe SPARC Version 9 Architecture is defined by the chapters and normative appendixes of thisdocument. A correct implementation of the architecture interprets a program strictly according tothe rules and algorithms specified in the chapters and normative appendixes. Only two classes ofdeviations are permitted:(1) Certain elements of the architecture are defined to be implementation-dependent. Theseelements include registers and operations that may vary from implementation to implementation,and are explicitly identified in this document using the notation “IMPL. DEP.#NN: Some descriptive text.” Appendix C, “SPARC-V9 Implementation Dependencies,”describes each of these references.(2) Functional extensions are permitted, insofar as they do not change the behavior of anydefined operation or register. Such extensions are discouraged, since they limit the portabilityof applications from one implementation to another. Appendix I, “Extending theSPARC-V9 Architecture,” provides guidelines for incorporating enhancements in animplementation.This document defines a nonprivileged subset, designated SPARC-V9-NP. This includes onlythose elements that may be executed or accessed while the processor is executing in nonprivilegedmode.The informative appendixes provide supplementary information such as programming tips,expected usage, and assembly language syntax. These appendixes are not binding on an implementationor user of a SPARC-V9 system.The Architecture Committee of SPARC International has sole responsibility for clarification ofthe definitions in this document.1.2.6 SPARC-V9 ComplianceSPARC International is responsible for certifying that implementations comply with the SPARC-V9 Architecture. Two levels of compliance are distinguished; an implementation may be certifiedat either level.Level 1:The implementation correctly interprets all of the nonprivileged instructions by anymethod, including direct execution, simulation, or emulation. This level supports userapplications and is the architecture component of the SPARC-V9 ABI.