[TUHS] PL/I stuff - was: Book Recommendation

John Cowan cowan at ccil.org
Sat Nov 27 07:22:15 AEST 2021

On Fri, Nov 26, 2021 at 3:32 PM Tom Ivar Helbekkmo via TUHS <
tuhs at minnie.tuhs.org> wrote:

Is there any relationship, other than pure coincidence, between this
> naming scheme and DEC's F, G, and H floating point number formats?

I don't think so.  The System/360 letters referred specifically to the
amount of memory available, so a D compiler would run on a D machine with
256K, and E/F/G were 512K/1M/2M.

The DEC floats were an extension of Fortran's exponent letters:  D=double,
E=generic, F=single.  G is a variant of F with a different
mantissa/exponent balance, and H is double double.   S and T floats came
later and were bit-for-bit compatible with IEEE binary32 and binary64
formats.  Lisp went a different way: to D, E, F they added S for small
floats and L for large floats.
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