cvs commit: src/lib/msun/src s_cosf.c s_sinf.c

[Bruce Evans]

bde         2005-11-28 06:15:10 UTC

  FreeBSD src repository

  Modified files:
    lib/msun/src         s_cosf.c s_sinf.c 
  Log:
  Exploit skew-symmetry to avoid an operation: -sin(x-A) = sin(A-x).  This
  gives a tiny but hopefully always free optimization in the 2 quadrants
  to which it applies.  On Athlons, it reduces maximum latency by 4 cycles
  in these quadrants but has usually has a smaller effect on total time
  (typically ~2 cycles (~5%), but sometimes 8 cycles when the compiler
  generates poor code).
  
  Revision  Changes    Path
  1.14      +2 -2      src/lib/msun/src/s_cosf.c
  1.14      +2 -2      src/lib/msun/src/s_sinf.c