1000

If the overflow flip-flop is a ZERO the Program Counter is advanced one
extra position and the next instruction in the sequence will be skipped.
The overflow flip-flop is cleared by this instruction. This flip-flop is
set by addition, subtraction, or division that exceeds the capacity of
the Accumulator. The overflow flip-flop is not cleared by arithmetic
operations which do not cause an overflow. Thus, a whole series of
arithmetic operations may be checked for correctness by a single szo.
The overflow flip-flop is cleared by the "Start" Switch.

_Skip on Plus In-Out Register_ (5 usec.)
spi Address 2000

If the sign digit of the In-Out Register is ZERO the Program Counter is
indexed one extra position and the next instruction in the sequence is
skipped.

_Skip on ZERO Switch_ (5 usec.)
szs Addresses 10, 20, ... 70

If the selected Sense Switch is ZERO, the Program Counter is advanced
one extra position and the next instruction in the sequence will be
skipped. Address 10 senses the position of Sense Switch 1, Address 20
Switch 2, etc. Address 70 senses all the switches. If 70 is selected all
6 switches must be ZERO to cause the skip to occur.

_Skip on ZERO Program Flag_ (5 usec.)
szf Addresses 0 to 7 inclusive

If the selected program flag is a ZERO, the Program Counter is advanced
one extra position and the next instruction in the sequence will be
skipped. Address 0 is no selection. Address 1 selects program flag one,
etc. Address 7 selects all programs flags. All flags must be ZERO to
cause the skip.

The instructions in the One Cycle Skip group may be combined to form the
inclusive OR of the separate skips. Thus, if address 3000 is selected,
the skip would occur if the overflow flip-flop equals ZERO or if the
In-Out Register is positive. The combined instruction would still take 5
microseconds.

* * * * *

_Operate Group_ (5 usec.)
opr Y Operation Code 76

This instruction group performs miscellaneous operations on various
Central Processor Registers. The address portion of the instruction
specifies the action to be performed.

_Clear In-Out Register_ (5 usec.)
cli Address equal 4000

This instruction clears the In-Out Register.

_Load Accumulator from Test Word_ (5 usec.)
lat Address 2000

This instruction forms the inclusive OR of the C(AC) and the contents of
the Test Word. This instruction is usually combined with address 200
(c