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Re: floating point war casualty list
On Tue, May 28, 2002 at 06:41:01PM -0400, Alan Lehotsky wrote:
>
> If I recall correctly, there are TWO (or more) PDP-11 floating point
> formats. I think it had something to do with word-order for the
> double-precision FP, but since it's been close to 25 years since I
> last did anything with the PDP-11 my memory is somewhat fuzzy.
As far as I know, there's F (single precision), D and G (two versions
of double), and H (extended).
I had been under the impression that real.c implemented F and G
formats, but from what people have been saying, real.c's VAX double is
D format (which may be wrong - G format is/was more popular), and its
VAX single is actually IEEE format, which is definitely wrong.
Be nice if we had all four and could switch between D and G at
runtime, but this is nontrivial to implement.
zw