SYSTEM opcodes available for custom instructions


James Robinson
 

I found this thread implying that certain SYSTEM opcodes are available for defining custom instructions:

https://github.com/riscv/riscv-isa-manual/issues/385

I didn't find any statement about this in the ISA spec.

Could somebody confirm whether these opcodes are supposed to be available?

Thank you,
James


Andrew Waterman
 

I don't think the spec was ever updated accordingly.  The issue was kept open as a placeholder until the spec change was proposed and written.


On Wed, Jun 9, 2021 at 6:40 AM James Robinson <jrobinson@...> wrote:
I found this thread implying that certain SYSTEM opcodes are available for defining custom instructions:

https://github.com/riscv/riscv-isa-manual/issues/385

I didn't find any statement about this in the ISA spec.

Could somebody confirm whether these opcodes are supposed to be available?

Thank you,
James