The Zfa extension provides several new instructions to improve the performance of floating point code for RISC-V.   Of particular importance is the fli instruction for loading predefined constants into FP registers, but there are also fround instructions and additional comparisons/min/max instructions.  The fli instructions will typically replace a load from the constant pool, so they're faster, smaller and reduce the data footprint of FP code as well.




Ventana: Jeff Law. Oversight & Review


Tsukasa OI authored the original binutils & gcc work – recently re-engaged

VRULL: Christoph Mullner has Tsukasa's work and has updated it per upstream review requests

Alibaba: Jin Ma has taken the mantle on Christoph's work





Development Timeline2H2023


Upstream Version

Development trunk

gcc-13 RISC-V coordination branch

Will turn into gcc-14, spring 2024

Available to all to use, but not official release from GCC project


Christoph Mullner (VRULL)

Jeff Law (Ventana)


None Remaining

All dependencies resolved



  • Minor bugfixes/enhancements to initial implementation landed.  No known issues at this point


  • Integrated Jin Ma's implementation plus some tests from Tsukasa's version
  • Minor outstanding issue on whether or not zvfh implies zfh which will be addressed (if necessary) in a follow-up patch.
  • Marking complete.


  • Alibaba (Jin Ma) started pushing on it again
  • Tsukasa has re-engaged as well with an implementation
    • Tsukasa has indicated he prefers the Alibaba/VRULL implementation
    • We'll look critically at both and try to pick the best overall implementation


  • Updated binutils support posted, reviewed and integrated in time for binutils-2.41 branch
  • QEMU posted and reviewed.  Unsure of integration status
  • Unblocks GCC work


  • binutils/assembler work blocked on assembler documentation
  • Note QEMU Zfa dependency
  • Code review for assembler & compiler looks good

– Dates on or before June 15 are estimates

  • Patches have been posted for both binutils and gcc.  Realistically one issue remains to be resolved before both can move forward.


  • Project reported as priority for 2H23