Comment 33 for bug 908508

We're now using a PPC macroassembler in TenFourFox (in our Google Code, this is issue 96). The reason I haven't pushed this upstream yet is because one of our contributors has an idea about reworking branching for better performance, and we are also implementing a software square root for PPCs that only have reciprocal square root estimates. Once this work is done, I'll put it up for review.

That isn't going to be all you would need to do for OpenBSD/powerpc, however. We also have some integration pieces to connect it to YarrJIT which are specific to the OS X ABI (I'm not going to bother with those since Mozilla doesn't support OS X PPC anymore) and in fact our prologue, epilogue and certain modifications to the methodjit assume OS X ABI and OpenBSD (IIRC) is SysV. Some Linux users who were looking at importing our nanojit are running into the same problem. Feel free to contact me privately if you want more information on this.

The long and short of it is, you should wait for the macroassembler bug to be posted by me (ETA a month or two), and then make whatever changes need to be made to YarrJIT. For now you're stuck with the YARR interpreter, sucky as it is.