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From: kirchner@uklirb.UUCP (Reinhard Kirchner)
Newsgroups: comp.arch
Subject: Things compilers never need ( was Re: Bandwidth and RISC vs. CISC )
Message-ID: <4641@uklirb.UUCP>
Date: 24 Apr 89 08:08:47 GMT
References: <38971@bbn.COM>
Organization: University of Kaiserslautern, W-Germany
Lines: 18

From article <38971@bbn.COM>, by slackey@bbn.com (Stan Lackey):
> 
> I have a real problem with anything that includes IEEE floating point
> AND calls itself a RISC.  IEEE FP violates every rule of RISC; it has
> features that compilers will never use (rounding modes), features that
                                          ^^^^^^^^^^^^^^

These things are NEEDED to generate accurate, verified results, not just
numbers you may trust or not ( remember: specific combinations of
algorithm + data may generate random numbers !! )

Therefor there are compilers which use these modes, and they are called
Pascal-SC and Fortran-SC and are made by mathematitians. These language
extensions actually would need not rounding modes, but instructions
with rounding control since they change the 'mode' from operation to
operation. Take a look at interval arithmetic to see examples.

R. Kirchner