Operating instructions
Sequencing through Programs
It
is
possible to manually sequence through a pro- If these procedures fail
the operator can follow the
gram, step by step, and examine each instruction procedures of the following section.
by reading the instruction register. This is accom-
plished with the following steps. (Assume the INSTR
Setting and Clearing Decimal Mode. Normally, the
switch
is
engaged)
:
program will set and clear the decimal mode. If for
any
reason the operator finds it necessary to do this
manually, the following procedures may be used. As
1-
Set the AUTO/MANUAL switch to MANUAL, previously mentioned, the DECIMAL MODE light on
the console will be on when the central processor
is in the decimal mode.
2.
Branch to the starting location of the pro-
gram to be examined:
a.
Set a BRU instruction into A register,
A.
TO SET THE
DECIMAL
MODE:
including the
address of the first in-
struction to be executed (BRU
is
octal
1.
Set the AUTO/'MtiNUt~L switch to MAN-
2600000). UAL.
b. Depress
A
to I switch. 2. Toggle the
RESET
LA.
switch.
3.
Press START switch once for each in-
struction to be executed; read the I register
and
P
counter after each step.
3.
Put the Set
Dec
Mode
instructiorl (octal
2506011) into the register.
4.
Depress the
A
to I switch.
Special Modes
5.
Depress the START switch.
Normally the program will set and clear out special
modes, such
as
the decimal mode, index group select,
6. Check to be sure the DECIMAL MODE
light
came on.
and the automatic
interrupt mode
(AIM).
The oper-
ator will seldom need to set these conditions, but may
B.
TO
CLEAR
DECIMAL
R/~ODE
(SET
BINARY
occasionally have to clear them manually. For in-
MODE)
:
stance, a program being debugged may be aborted, and
the special options are left on.
The procedure for clearing AIM, index group select,
and decimal mode are described in the following
paragraphs. If these procedures fail, more elaborate
procedures are given in the sections
immediatelyfol-
lowing.
Clearing with PWR ON.
A quick way to turn off the
automatic interrupt mode, clear out index group
select, and
change from the decimal mode to binary
is
to use the PWR ON switch, following these steps
(assume power
is
on to central processor):
1.
Set the
AUTO/MANUAL
switch to MANUAL.
2. Set the
INSTR/WORD
switch to WORD.
3.
Depress PWR ON switch.
4.
Make visual checks to see
if
goal
is
accom-
plished.
1.
Set the AUTO/MANUAL switch to MAN-
UAL.
2.
Toggle the
RESET
A
switch.
3.
Put the Set Binmode instruction (octal
2506012) into the
A
register.
4.
Depress the A to I switch.
5. Depress the START switch.
6. Be sure the DECIMAL MODE light
went off.
Automatic Interrupt Mode.
The Automatic Interrupt
Mode, which
is
present as an optional feature on some
GE-225
Systems,
is
usually turned on and off by
program control. Occasionally, however,
it
may be
desired to turn this mode of operation on or off man-
ually as follows:
A.
MANUAL AIM TURN-ON PROCEDURE
5. Set the
INSTR/WORD switch to INSTR,
1.
Set the
AUTO/MANUAL
switch to the
MANUAL position.
At step
4,
note tha t the DECIMAL MODE light on the
console will go out AIM light on control console
will go out (if on), and index group lights will go out.
2.
If the program
is
to be resumed at the
point of manual interruption, depress