Charles Mills writes:
Reentrant code is typically more scattered in its storage references, which
increases paging
overhead (at least in theory).
Properly qualified, this once good theory can be rescued. Locality of data
reference is good, and locality of instruction reference is good. Global
locality of reference, intermixing data and instructions, is very, very bad.
z/Architecture processors have been optimized for (mostly)
compiler-generated reentrant code, and they are very bad at executing
non-reentrant code.
This is not really an issue for compromise or for statesmanlike fatuities of
the form 'Reentrant code has important uses; on the other hand there is
scope for non-reentrant constructions'. As I indicated in my OP, there is
no longer any rationale or excuse for writing non-reentrant code.
En passant 1, I am familiar with the quondam geometric use of the word
'reentrant'. It is no longer current, and in any case it is not a bar to
another use in another place. In his treatise on the astrolabe Chaucer
described himself as "a mere lewd compilator"; but his use of the term
'lewd' to mean that he was a layman, not in holy orders, is not a bar to its
modern uses.
En passant 2, in English 'a and b and c' and 'a; b; c' are indeed
equivalent. Moreover, the semicolon is mandatory when the conjunction is
omitted. The converse notion that a semicolon may not be used when a
conjunction is used is, however, ridiculous (and ridiculed memorably by
Fowler). The other major use of semicolons (outside of ALGOL-like
statement-level procedural languages) is as separators for independent
clauses (linked by conjunctions) that themselves contain commas.
John Gilmore
Ashland, MA 01721-1817
USA
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