Ron Parker <ron### [at] povrayorg> wrote:
: Not really.  FLD with a 32-bit real operand is 20 clocks, as opposed to the
: 64-bit version at 25 clocks.  FST is 44 vs. 45 clocks.  FMUL is 27-35 clocks
: for a float, or 32-57 for a double.  FDIV is 89 or 94.  So floats are faster,
: under ideal conditions, but not by any significant amount.  (This data is for 
: the 386.  Other processors vary, of course.  Intel no longer seems to publish
: this data, for the obvious reason that pipelining and other optimizations 
: make it useless.)

  As someone already said, this is not true anymore for pentium-class
processors.
  In a plain pentium (if I remember right) the fld takes about 6 clocks
and fst about 3 (for both float and double) and fmul takes 1 clock (amazingly)
in most cases.
  In a P-II it's even faster.

  On the other hand, all values are internally converted to 80 bits floating
numbers by the FPU (this is usually the long double type in C compilers for
PC). However, it's not faster to use the long double type. Double is faster.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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