km@mathcs.emory.edu (12/02/89)
I remember seeing somewhere that the Sun 4/2xx FPU-1 does sqrt in software, but the FPU-2 did it in hardware. Now the questions: What about the 4/60 and 4/3xx. Software or hardware sqrt's? What is the speedup factor for hardware sqrt? What is the easiest way to get the C compiler to use the hardware sqrt's if they exist? Apparently there is more to it than replacing sqrt with Fsqrt in the source, and putting /usr/lib/libm.il on the command line. I just did a benchmark that showed a Sun 3/60 with inline 68881 sqrts (in Fortran), was twice as fast as a Sun 4/280 without inline sqrts (in either C or Fortran).