riscv_p_ext

Draft Extension: P

• Branch: riscv-p-ext
• Tracking PR: #72 (view Pull Request and Diff)
• Mailing List:
  • Not yet

Feature Description

The last GNU Binutils port of P-extension proposal is by Sinan LIN's implementation based on GNU Binutils 2.36.1 and a bit older draft specification version: 0.9.4.

My implementation is a testbed of my proposed common framework and...

• Based on GNU Binutils master branch
• Implements P-extension proposal version 0.9.11 (latest) except WEXT instruction alias
  • WEXT is formerly an independent instruction but moved to an alias (implemented with FSR). However, this is considered harmful to toolchains (assemblers).
• 6 encoding differences between Sinan's implementation (excluding WEXT)
  • 2 are caused by different P-extension version
  • 4 are caused by Sinan's implementation's bug while partially adopting latest draft of P-extension (PACK and PACKU operand order is different).
• Utilizes X operand type (introduced with T-Head custom extension but regarded as general purpose)