http://www.chips.ibm.com/products-nojs/x86-nojs/x86dev/l3devibm6x86.html
Those of you keen on detection should probably grab a copy of the IBM doco
describing how to do detection in a reasonable fashion (i.e. without
getting invalid instruction on CPUID ;-) as doc #40204 at:
http://www.chips.ibm.com/products-nojs/x86-nojs/x86dev/l4devapp6x.html
Once you get 6x86 detection sorted on common chips, it should be tested
on those older DLC (386 pin compatible) and Blue-Lightning IBM chips
to make sure it doesn't do anything strange on them, since they will
also pass the cyrix "division test" described in #40204.
Hope this helps you mob out a bit.
Paul.