Control Data 3100 Reference Manual page 202

CLEAR - An operation that removes a quantity from a register by placing every stage
of the register in the "0" state. The initial contents of the register are destroyed by
the Clear operation.
COMMAND - Synonymous with Instruction.
COMPILER - A program with the compatability to generate more than one line of
machine code (instruction or data word) from one source language statement.
COMPLEMENT-Noun: See One's Complement or Two's Complement. Verb: A com-
mand which produces the one's complement of a given quantity.
CONTENT - The quantity or word held in a register or storage location.
CORE - A ferromagnetic toroid used as the bi-stable device for storing a bit in a
memory plane.
COUNTER - A register or storage location, the contents of which may be incremented
or decremented.
D REGISTER - A 4-bit field length register used for BCD operations.
DOUBLE PRECISION -Providing greater precision in the results of arithmetic opera-
tions by appending 24 additional bits of lesser significance to the initial operands.
ENTER - The operation where the current contents of a register or storage location are
replaced by some defined operand.
EQUALIZE - Adjusting the operand of the algebraically smaller exponent to equal the
larger, prior to adding or subtracting the floating point coefficients.
EXCLUSIVE OR-A logical function in Boolean algebra that is satisfied (has the value
"I") when any of its terms are "I". It is not satisfied when all its terms are "I" or
when all its terms are "0".
EXECUTION ADDRESS-The lower 15 or 17 bits of a 24-bit instruction. Most often
used to specify the storage address of an operand. Sometimes used as the operand.
EXIT - Initiation of a second control sequence by the first, occurring when the first is
near completion; the circuit involved in exiting.
F REGISTER-Program Control register. Holds a program step while the single 24-bit
instruction contained in it is executed.
FAULT-Operational difficulty which lights an indicator or for which interrupt may be
selected.
FIXED POINT-A notation or system of arithmetic in which all numerical quantities
are expressed by a predetermined number of digits with the binary point implicitly
located at some predetermined position; contrasted with floating point.
FLIP-FLOP (FF)-A bi-stable storage device. A "I" input to the set side puts the FF
in the "I" state; a "I" input to the clear side puts the FF in the "0" state. The
FF remains in a state indicative of its last "1" input. A stage of a register consists of a FF.
FLOATING POINT - A means of expressing a number, X, by a pair of numbers, Y and
Z, such that X
=
Yn Z . Z is an integer called the exponent or characteristic; n is a base,
usually 2 or 10; and Y is called the fraction or mantissa.
FUNCTION CODE - See Operation Code.
INCREASE - The increase operation adds a quantity to the contents of the specified
register.
INDEX DESIGNATOR-A 2-bit quantity in an instruction; usually specifies an index
register whose contents are to be added to the execution address; sometimes specifies
the conditions for executing the instruction.
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