Inexact floating-point compare

Does anyone know of any machines, that have a floating-point compare
instruction, where that instruction is not exact?  That is, some of
the value bits of the floating-point numbers are ignored.  Or, if
the compare is done internally as a subtract, the subtract results in
an underflow (so two different numbers near the minimum normalized
value, when subtracted produce a subnormal number) that is then 
flushed to zero, so compare equal.
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Fred J. Tydeman        Tydeman Consulting
[EMAIL PROTECTED]      Programming, testing, numerics
+1 (775) 287-5904      Vice-chair of J11 (ANSI "C")
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