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Non-Standard Extensions - RISC-V
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Because RISC-V is designed to provide the foundation for more specialized hardware, RISC-V offers the ability to extend the architecture with non-standard extensions which refers to additional instructions offered by third parties that are not part of RISC-V officially recognized standard extensions.


In addition to the RISC-V standard extensions, the ISA allows for custom third party ISA. The intention of custom extensions is to allow designers to implement additional highly specialized instructions.

  • Xabc - Non-standard User-level extension "abc"
  • SXabc - Non-standard Supervisorlevel extension "abc"

For example RV32IXabc.

Non-standard extensions[edit]

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