🚀 go-pugleaf

In article <817@acorn.co.uk>, RWilson@acorn.co.uk writes:
> Well us hardware folks (Acorn) have come to your rescue: the floating point
> system for the Acorn RISC Machine (VLSI Technology VL86C010 and VL86C020)
> provides the rounding modes as part of the instruction. ...
> 
> One little thing: ARM based computers start at 649 pounds in the UK. And you
> can't buy them in the states at all. Must be something in your culture
> which doesn't want control over rounding modes :-)!
> 
> --Roger Wilson

Sorry to burst your bubble Roger, but the AT&T WE32206 Math Acceleration
Unit chip provides BOTH modes AND per-instruction rounding.  For instance,
you could set the '206 to the "round to nearest" mode,
then if necessary override the current mode for an instruction or two.
I wrote an assembler for this chip that accepted an optional rounding mode
suffix on each floating-point instruction.  Thus, if "mfaddd" is a
double-precision addition, "mfaddd.rz" forces the addition to be rounded
to zero, regardless of the current rounding mode.

This chip is in the newest AT&T 3B2 models, but I don't think the production
assembler supports this feature of the WE32206.

Dave Wolverton
AT&T
daw@attunix.att.com