Jonas Maebe wrote:
Provided that one calls a Z80 16-bit :-) More to the point: do any
current CPUs have e.g. vector operations that suggest a realistic
maximum size?
The current x86's bit test/set instructions support addressing the
complete 32/64 bit address space. But the original 8086 didn't have any
vector instructions at all. Again: this limitation is unrelated to
instruction sets, it's about deciding on a point at which you're going
to waste a lot of memory by using a plain bitmap.
For larger sets... OK, how /does/ one declare a set of UTF-8 characters?
An UTF-8 character is not an ordinal data type and hence support for
"set of <utf-8 character>" is orthogonal to support for larger sets. If
you store them in strings or arrays, then you need a hashtable of
strings or arrays (and/or support for sets of strings or arrays, which
would probably be implemented using... a hashtable).
That was pretty much my gist. Since these days Unicode is larger than
65536 codepoints I don't think there's any advantage to expanding sets
from 256 to 65536 elements, efficient operations on sparse arrays of
256-element sets would be far better.
A modest expansion to be able to handle something like a bitboard for Go
might be attractive though.
--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
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