lear Accumulator), so that C(AC) will equal the contents of the Test
Word Switches.

_Complement Accumulator_ (5 usec.)
cma Address 1000

This instruction complements (makes negative) the contents of the
Accumulator.

_Halt_
hlt Address 400

This instruction stops the computer.

_Clear Accumulator_ (5 usec.)
cla Address 200

This instruction clears (sets equal to plus 0) the contents of the
Accumulator.

_Clear Selected Program Flag_ (5 usec.)
clf Address 01 to 07 inclusive

The selected program flag will be cleared. Address 00 selects no program
flag, 01 clears program flag 1, 02 clears program flag 2, etc. Address
07 clears all program flags.

_Set Selected Program Flag_ (5 usec.)
stf Address 11 to 17 inclusive

* * * * *

_In-Out Transfer Group_ (5 usec. without in-out wait)
iot x Y Operation Code 72

The variations within this group of instructions perform all the in-out
control and information transfer functions. If bit six (normally the
Indirect Address bit) is a ONE, the computer will halt and wait for the
completion pulse from the device activated. When this device delivers
its completion, the computer will resume operation of the instruction
sequence.

An incidental fact which may be of importance in certain scientific or
real time control applications is that the time origin of operations
following an in-out completion pulse is identical with the time of that
pulse.

Most in-out operations require a known minimum time before completion.
This time may be utilized for programming. The appropriate In-Out
Transfer is given with no in-out wait (bit six a ZERO). The instruction
sequence then continues. This sequence must include an iot instruction
which performs nothing but the in-out wait. This last instruction must
occur before the safe minimum time. A table of minimum times for all
in-out devices is delivered with the computer. It lists minimum time
before completion pulse and minimum In-Out Register free time.

The details of the In-Out Transfer variations are listed under
Input-Output.

The mnemonic codes and addresses for the standard equipment are:

_Read Paper Tape Alphanumeric Mode_
rpa Address 1

_Read Paper Tape Binary Mode_
rpb Address 2

_Typewriter Output_
tyo Address 3

_Typewriter Input_
tyi Address 4

_Punch Paper Tape Alphanumeric Mode_
ppa Address 5

_Punch Paper Tape Binary Mode_