the normal execution
time of the instruction, i.e., the time with no indexing and no
deferring, the mnemonic code of the instruction, and the operation code
number. The notation used requires the following definitions. The
contents of a register Q are indicated as C(Q). The address portion of
the instruction is indicated by Y. The index register address of an
instruction is indicated by x. The effective address of an operand is
indicated by Z. Z may be equal to Y or it may be Y as modified by
deferring or by indexing.

Indexable Memory Instructions

Arithmetic Instructions

_Add_ (10 usec.)
add x Y Operation Code 40

The new C(AC) are the sum of C(Z) and the original C(AC). The C(Z) are
unchanged. The addition is performed with 1's complement arithmetic.

If the sum exceeds the capacity of the Accumulator Register, the
overflow flip-flop will be set (see Skip Group instructions).

_Subtract_ (10 usec.)
sub x Y Operation Code 42

The new C(AC) are the original C(AC) minus the C(Z). The C(Z) are
unchanged. The subtraction is performed using 1's complement
arithmetic.

If the difference exceeds the capacity of the Accumulator, the overflow
flip-flop will be set (see Skip Group instructions).

_Multiply_ (approximately 25 usec.)
mul x Y Operation Code 54

The C(AC) are multiplied by the C(Z). The most significant digits of the
product are left in the Accumulator and the least significant digits in
the In-Out Register. The previous C(AC) are lost.

_Divide_ (approximately 90 usec.)
div x Y Operation Code 56

The Accumulator and the In-Out Register together form a 70 bit dividend.
The high order part of the dividend is in the Accumulator. The low order
part of the dividend is in the In-Out Register. The divisor is (Z).

Upon completion of the division, the quotient is in the In-Out Register.
The remainder is in the Accumulator. The sign of the remainder is the
same as the sign of the dividend. If the dividend is larger than C(Z),
the overflow flip-flop will be set and the division will not take place.

Logical Instructions

_Logical AND_ (10 usec.)
and x Y Operation Code 02

The bits of C(Z) operate on the corresponding bits of the Accumulator to
form the logical AND. The result is left in the Accumulator. The C(Z)
are unaffected by this instruction.

Logical AND Function Table

AC Bit C(Z) Bit Result
0 0 0
0 1 0