more talking to the press.

From: Patrick Rigney <patrick_at_evocative.com>
Date: Wed Nov 12 21:00:03 2003

Eric Smith wrote:
>
> This instruction is especially useful, as it allows the software to
> directly implement an NFA (nondeterministic finite automaton) without
> having to transform it into a DFA (deterministic). NFAs are used for
> regular expression matching and lexical analysis, but the transformation
> to a DFA as needed on processors without the BBW instruction can be
> expensive in both time and memory.
>
> On a more serious note, many state-of-the-art processors do sort of
> implement "branch both ways" in the sense that they do speculative
> execution of both paths then discard the results on one path once the
> condition is resolved. A limited form of speculative execution was
> used by the IBM 7030 Data Processing System (AKA "Stretch"), introduced
> in 1961. I'm not aware of any other production systems with speculative
> execution that are on-charter for this list (e.g., introduced before
> 12-nov-1993).
>
> Eric

Notice to all: I'm claiming an extra geek point because this entire message
makes perfect sense to me. --Patrick
Received on Wed Nov 12 2003 - 21:00:03 GMT