CfgCyrix Device Driver version 1.0
		       Tom Warren/Tech Guys SW
			   September, 1992

    CfgCyrix is intended to allow the technical user to upgrade their
    386DX-based system to take advantage of the new, inexpensive i486-
    like Cyrix Cx486DLC CPU.

    While it is possible to get a performance increase just by installing
    a 486DLC in place of the existing i386 CPU, it seems foolish not to
    take advantage of the 486DLC's built-in 1K cache. I wrote CfgCyrix to
    allow you to twiddle the cache config settings to achieve maximum
    performance and maximum compatibility with your current software/hardware.

    On a typical system (OPTi 386/33, with 64KB write-back cache), I
    recorded the following results (Landmark Speedbar 2.00):

   *base system, i386/33 CPU:    51.99 MHz
    same system, Cx486DLC CPU:   78.32 MHz  (Cyrix cache disabled, default)
    same system, Cx486DLC CPU:  108.29 MHz  (Cyrix cache enabled, /E1 /F1)

   * 4MB RAM, 64KB WB cache enabled, no coprocessor, clean CONFIG.SYS

    CfgCyrix command line syntax is available by 'typing' the file to
    the console:

    TYPE CFGCYRIX.SYS

      CfgCyrix version 1.0  Copyright (C) 1992 Tom Warren/TechGuys SW

      Usage: DEVICE=CFGCYRIX.SYS /A0 /B0 /C0 /D0 /E1 /F1 /H0 /K0 /R0 /S0

      A0 = A20M# input pin (A20 mask) disabled, A1 = enabled
      B0 = BARB (flush on HOLD) disabled, B1 = enabled
      C0 = 2-way set-associative cache, C1 = direct-mapped cache
      D0 = Debug flag disabled, D1 = enabled (verbose initialization info)
      E0 = mark 640K-1Meg region as cacheable, E1 = mark region as noncacheable (NC0)
      F0 = FLUSH# input pin (cache flush) disabled, F1 = flush enabled
      H0 = set first 64K of each 1Meg boundary cacheable (real/V86 mode),
           H1 = set first 64K of each 1Meg boundary noncacheable (NC1)
      K0 = KEN# input pin (cache enable) disabled,K1 = cache enabled
      R0 = RPLSET/RPLVAL# output pins disabled (floated), R1 = enabled
      S0 = SUSP# input/SUSPA# output pins disabledS1 = enabled

    Typically, the only bit that really needs to be set is F1, which
    enables the FLUSH# pin.  It might also be prudent to set E1, which
    disables caching of the 640K - 1Meg expansion ROM region.

    Note that on the so-called ALPHA part (Rev A of the 486xLC) there
    is a bug that disables caching from _512K_ to 1Meg when E1 is set.
    I'm not sure how you can distinguish the ALPHA part from the BETA
    (Rev B) part, but Cyrix may know if you call them @ (214) 234-8387.
    They should have a data book available for the 486DLC, also.

    Also, note that the Cyrix will appear as a 486 to most (all)
    benchmark/diagnostic software, which is OK, except when it comes
    to timing.  The Cyrix CPU executes some instructions much faster than
    the i486, and may confuse code that is attempting to calculate
    the CPU speed of the chip.  Use WhatCPU.COM, included in this
    archive, if you need to check the true CPU clock speed.

    Experiment with the settings until you achieve the best performance
    on your system.  Run all of your "sensitive" software, such as
    Windows, QEMM, etc., until you're happy with the settings, then
    'lock' them into your CONFIG.SYS and enjoy!


    Users of CfgCyrix and WhatCPU must accept this disclaimer of warranty:

    The CfgCyrix and WhatCPU utilities are supplied as is.
    The author disclaims all warranties, expressed or implied,
    including, without limitation, the warranties of merchantability
    and of fitness for any purpose.  The author assumes no liability
    for damages, direct or consequential, which may result from the
    use of CfgCyrix or WhatCPU.

    CfgCyrix and WhatCPU are "shareware programs" and are provided at
    no charge to the user for evaluation.  Feel free to share them with
    your friends, but please do not give them away altered or as part of
    another system. The essence of "user-supported" software is to provide
    personal computer users with quality software without high prices, and
    yet to provide incentive for programmers to continue to develop new
    products.

    If you find CfgCyrix and/or WhatCPU to be useful programs and continue
    to use them after a reasonable trial period (30 days), I would appreciate
    a contribution of $5.00 for my time and knowledge.  This will entitle you
    to updates and bug fixes, as well as any new utilities I might distribute.

    Anyone distributing CfgCyrix or WhatCPU for any kind of remuneration must
    first contact me (via CompuServe) for authorization.

    You are encouraged to pass a copy of CfgCyrix and WhatCPU along to
    your friends and collegues for evaluation.  Please encourage them
    to register their copy if they find that they can use it.

    Tom Warren, Moorpark, CA  - [CompuServe 76167,1572]