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PC 80486 ** CORRECTION **

Ken Fasman ken at oscar.welch.jhu.edu
Mon Jan 25 14:39:38 EST 1993

In article <1993Jan25.170138.10928 at welchgate.welch.jhu.edu>, ken at oscar.welch.jhu.edu (Ken Fasman) writes:
|> My understanding of the various members of the Intel 80386 and 80486 families
|> are as follows:
|> Chip		Internal	External	Floating
|> Designation	Data Path	Data Path	Point Unit?
|> -----------	---------	---------	-----------
|> 386DX	32 bits		32 bits		No
|> 386SX	32 bits		16 bits		No
|> 486DX	32 bits		32 bits		Yes
|> 486SX	32 bits		16 bits		Yes
|> Please note that Intel uses the "SX" designation to denote the narrower 
|> external data path, NOT the presence or absence of a math coprocessor.

This is not quite right!  It turns out that the 486SX had its floating point 
unit disabled in the original chip, and removed from the die altogether in 
later versions.  That is, the 486SX has a 32 bit internal data path, a 16 bit 
external data path, and NO FLOATING POINT COPROCESSOR.

Thanks to Ray Duncan and Peter Li for pointing out the error of my ways.  :-(


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