----Original Message----
>From: Paul Schlie
>Sent: 08 June 2005 15:53
>> From: Robert Dewar
>> There is nothing imprecise about IEEE floating-point operations
>
> - agreed, however nor is it mandated by most language specifications,
> so seemingly irrelevant.
I refer you to "Annex F (normative) IEC 60559 floating-point arithmetic" of the
C language spec. "Normative" implies a mandate, does it not?
F.1 Introduction
1 This annex specifies C language support for the IEC 60559 floating-point
standard. The IEC 60559 floating-point standard is specifically Binary
floating-point arithmetic for microprocessor systems, second edition (IEC
60559:1989), previously designated IEC 559:1989 and as IEEE Standard for Binary
Floating-Point Arithmetic (ANSI/IEEE 754−1985). IEEE Standard for
Radix-Independent Floating-Point Arithmetic (ANSI/IEEE 854−1987) generalizes
the binary standard to remove dependencies on radix and word length. IEC 60559
generally refers to the floating-point standard, as in IEC 60559 operation, IEC
60559 format, etc. An implementation that defines
__STDC_IEC_559__ conforms to the specifications in this annex. Where a binding
between the C language and IEC 60559 is indicated, the IEC 60559-specified
behavior is adopted by reference, unless stated otherwise.
> - as above (actually most, if inclusive of all processors in production,
> don't directly implement fully compliant IEEE FP math, although many
> closely approximate it, or simply provide no FP support at all;
Pretty much every single ix86 and rs6000, and many m68 arch CPUs provide
last-bit-exact IEEE implementations in hardware these days. Your statement is
simply factually incorrect.
cheers,
DaveK
--
Can't think of a witty .sigline today....
