JFCL
/jif'kl/, /jaf'kl/, /j*-fi'kl/ (obsolete) To cancel or annul something.
"Why don't you jfcl that out?"
The fastest do-nothing instruction on older models of the
PDP-10 happened to be JFCL, which stands for "Jump if Flag set and then CLear the flag"; this does something useful, but is a very fast no-operation if no flag is specified.
Geoff Goodfellow, one of the jargon-1 co-authors, had JFCL on the licence plate of his BMW for years.
Usage: rare except among old-time PDP-10 hackers.
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Jargon File]
