- Joined
- Dec 24, 2001
- Location
- Shasta Lake, California
Looking back at this article (http://chip-architect.com/news/2003_09_21_Detailed_Architecture_of_AMDs_64bit_Core.html), it looks like the x87 and see pipelines are shared on the K8. I think it would be possible to execute sse and x87 code in parallel if you had seperate pipelines for x87 and sse code, even though they use the same registers. You might be able to get around it using register renaming (eliminating false regiister dependencies), or you could just use different registers (x86-64 provides 16 sse registers). I believe that the intention of -mfmpath=sse,387 was to utilize both units at once, assuming seperate pipelines, not to select the best instruction to use for the operation.
