:JFCL: /jif'kl/, /jaf'kl/, /j*-fi'kl/ vt., obs. (alt.
`jfcl') 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 license plate of his
BMW for years. Usage: rare except among old-time PDP-10
hackers.
-- The AI Hackers Dictionary
`jfcl') 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 license plate of his
BMW for years. Usage: rare except among old-time PDP-10
hackers.
-- The AI Hackers Dictionary
Related:
- PDP-10: [Programmed Data Processor model 10] n. The machine that
made timesharing real.
It looms large in hacker folklore because of its adoption in the mid-1970s by many university computing facilities and research labs, including the MIT AI Lab, Stanford, and CMU.... - o-op: /noh'op/ alt. NOP /nop/ [no operation] n. 1.
(also v.) A machine instruction that does nothing (sometimes used in assembler-level programming as filler for data or patch areas, or to overwrite code to be removed in binaries).... - JRST: /jerst/ [based on the PDP-10 jump instruction] v.
obs. To suddenly change subjects, with no intention of returning to the previous topic.... - ASCIIbetical order: /as'kee-be'-t*-kl or'dr/ adj.,n.
Used to indicate that data is sorted in ASCII collated order rather than alphabetical order.... - flag day: n. A software change that is neither forward- nor
backward-compatible, and which is costly to make and costly to
reverse.
Can we install that without causing a flag day for all users?... - flag: n. A variable or quantity that can take on one of two
value
a bit, particularly one that is used to indicate one of two outcomes or is used to control which of two things is to be done.... - bum: 1. vt. To make highly efficient, either in time or space,
often at the expense of clarity.
I managed to bum three more instructions out of that code.... - DPB: /d*-pib'/ [from the PDP-10 instruction set] vt.
To plop something down in the middle. Usage: silly.... - mode bit: n. A {flag}, usually in hardware, that selects between
two (usually quite different) modes of operation.
The connotations are different from {flag} bit in that mode bits are mainly written during a boot or set-up phase, are seldom explicitly read, and seldom change over the lifetime of an ordinary program....
