Processor-specific code

[Robert Dewar]

Richard Earnshaw wrote:

> Not all environments can change the rounding mode dynamically.  For
> example, on the FPA co-processor for ARM, rounding is set by the
> instruction selected -- so the concept of having an environment variable
> to control this is meaningless.

Right, such a feature obviously does not apply to hardware that is this
far from the IEEE standard (which requires dynamic control). The Alpha
architecture has similar problems.