
Modes -c5000 and -c6000
~~~~~~~~~~~~~~~~~~~~~~~
Experimental modes, not supported in future versions.


Speed Tuning
~~~~~~~~~~~~
There are several optimized routines especially for the -c3000 and -c4000
modes. Normally these are selected by the program itself. You can overwrite
these settings via the enviroment variables:

  RA	0...3
  RC	0...7
  RCA	0...5

RA and RC affects encoding, RCA decoding. Currently they are tuned for 

  Pentium 133
  Athlon 0.7
  Pentium 4/1.7

Other CPUs may be faster with non-default settings.

  RA = 0	C code
  RA = 1	Inline MMX code  (Windows only)
  RA = 2	extenal MMX code
  RA = 3	SSE2 code (only P4)

  RC = 0	C code
  RC = 1	Inline MMX code  (Windows only)
  RC = 2	extenal MMX code
  RC = 3	SSE2 code (only P4)
  RC = 4	FPU code
  RC = 5	FPU/FXCH code (Pentium Classic)
  RC = 6	16 bit code
  RC = 7	32 bit code

  RCA = 0	C code
  RCA = 1	Inline MMX code  (Windows only)
  RCA = 2	extenal MMX code
  RCA = 3	SSE2 code (only P4)
  RCA = 4	FPU code
  RCA = 5	FPU/FXCH code (Pentium Classic)

