Article View: comp.arch
Article #1887Re: Making Rounding Modes Usable
From: Reinhard Kirchner
Date: Thu, 17 Aug 1989 15:38
Date: Thu, 17 Aug 1989 15:38
44 lines
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2305 bytes
From article <1989Jul21.035825.27704@cs.rochester.edu>, by crowl@cs.rochester.edu (Lawrence Crowl):
> There are a number of reasons that rounding modes are not used more. And
> unfortunately, the reasons feed each other.
>
> - Programming languages historically do not support rounding modes.
> - So, such use has been restricted generally to changing modes between program
> runs (for a warm fuzzy).
> - So, specifying the rounding modes is part of device setup and not part of
> the operation instruction.
> - So, changing the rounding mode is a difficult and time consuming operation.
> - So, newer programming languages tend not to support rounding modes because
> the designers know users will not pay the cost.
>
> We can break the cycle and provide good access to faster, more robust floating
> point programs with the following efforts.
>
> - Specify the rounding mode as part of the operation. In essence, I am saying
> that rounding MODES are a self-defeating way of looking at the capability.
> We should have ADD-ROUNDING-UP and ADD-ROUNDING-DOWN, etc.
> - Make these operations available in a programming language.
> - Make these operations convenient in a programming language, e.g. operator
> overloading in Ada and C++.
>
I have been in hollidays, so this comes a little late.
I hate to say it again and again:
There are languages which have rounding with their operations, so you
can write
x := y +> z; (* + with round upward *)
and this also with < e.g. +<, for all operations.
These languages are PASCAL-SC and FORTRAN-SC.
I will stop here since I know this is not a language group -:).
Only one sentence: The only thing these languages lack are vendors who
port them to their hardware ( No market they say )
R. Kirchner
kirchner@uklirb.uucp
kinf89@dkluni01.bitnet ( preferred )
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.csd.uwm.edu!cs.utexas.edu!uunet!mcvax!unido!uklirb!kirchner From: kirchner@uklirb.UUCP (Reinhard Kirchner) Newsgroups: comp.arch Subject: Re: Making Rounding Modes Usable Message-ID: <6421@uklirb.UUCP> Date: 17 Aug 89 15:38:02 GMT References: <1989Jul21.035825.27704@cs.rochester.edu> Organization: University of Kaiserslautern, W-Germany Lines: 44