SSE FPU parallel

Question

I was wondering if it would be possible to use SSE in parallel with x87. So consider the following pseudo code,

1: sse_insn 2: x87_insn

Would the pipeline execute 1 and 2 in parallel assuming they can be executed in parallel?

Answer 1

In all modern (and older) processors, the x87 and SSE instructions use the same execution units, so it's UNLIKELY that you will benefit much from this sort of code. There may be very special cases where you can trick the processor into running for example a x87 divide in parallel with an SSE add, or something like that, but if you are simply doing a big loop of similar operations, there is almost certainly no benefit.