Instruction Set Architecture
- Non-Standard Extensions
- Addressing Modes
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"
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