Specifications

other lights; (Fetch, Execute, Source, Destination; the.Address lights, and the
Address and Data registers) will be flickering. If the run light is on, and none
ofthe other indicators are flickering, the system could. be executing a “wait”
instruction which waits for an interrupt.
While in the halt mode;if the operator wishes to do a siqgle instruction, he
places the S/INST-S/CYCLE switch in the S/lNST position and depresses
CONT. When CONT is depressed, the console momentarily passes control to
the processor, allowing the machine to execute one instruction before regain-
.ing control. Each time the CONT switch is depressed, the machine will
execute one instruction.
.
Similarly, if the operator wishes to have the machine perform a single bus
cycle, he places the S/INST-S/CYCLE switch in the S/CYCLE position and
presses CONT. The machine will then perform one complete bus cycle and
halt. The operator cannot do an,examine or deposit function at the end of a
single bus cycle unless the cycle ends coincidental with the end of an in-
struction. This prevents altering machine flow. Only when the machine is at
the end of an instruction and in the halt mode’can the examine or deposit
functions operate.
To start the machine running its program again, the operator places the
ENABLE/HALT switch in the ENABLE position, and depresses the CONT
switch.
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