Question related to printf

[David Thompson]

Do you have an authoritative reference for referring to the sign bit
off states as "positive" rather than "non-negative"? I'm not familiar
with any such usage being commonplace.

Not authoritative, and not universal although fairly common IME.

The easiest examples for me to remember are several DEC 2sC machines I
was most familiar with: PDP-8 'Skip Minus' < 0 and 'Positive' >= 0
('microcoded' with Zero/Non so you could easily get the useful cases
of strictly-greater and less-or-equal) and PDP-11 plain-sign 'Branch
PLus' >= 0 and 'MInus' < 0 (but the corrected-sign versions used
arithmetically correct GreaTer, Greater-or-Equal, Less, Less-or-Equal;
and the unsigned-carry versions used HIgh-or-Same and LOw).
ISTR some other (2sC) minis also did this, maybe DG and HP,
as well as the Motorola 6800 and 68k which sortof followed PDP-11;
and IIRC Intel 8080 et al 'Jump Positive' >= 0 and 'Negative' < 0.

OTOH IBM S/360 et seq had proper three-value (four on some errors)
condition-code; and DEC PDP-10 had no condition-code at all, but
three-way jump and skip conditions. Apparently IBM 70?? also did as
that's reportedly where original Fortran 'arithmetic' IF came from.

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