cvs commit: src/lib/msun/src e_rem_pio2f.c

[Bruce Evans]

bde         2005-10-29 16:34:50 UTC

  FreeBSD src repository

  Modified files:
    lib/msun/src         e_rem_pio2f.c 
  Log:
  Use double precision to simplify and optimize arg reduction for small
  and medium size args too: instead of conditionally subtracting a float
  17+24, 17+17+24 or 17+17+17+24 bit approximation to pi/2, always
  subtract a double 33+53 bit one.  The float version is now closer to
  the double version than to old versions of itself -- it uses the same
  33+53 bit approximation as the simplest cases in the double version,
  and where the float version had to switch to the slow general case at
  |x| == 2^7*pi/2, it now switches at |x| == 2^19*pi/2 the same as the
  double version.
  
  This speeds up arg reduction by a factor of 2 for |x| between 3*pi/4 and
  2^7*pi/4, and by a factor of 7 for |x| between 2^7*pi/4 and 2^19*pi/4.
  
  Revision  Changes    Path
  1.14      +22 -97    src/lib/msun/src/e_rem_pio2f.c