HP 3000 III Series Manual page 122

The contents of the SWITCH REGISTER
(0:15) switches are stored in memory
at the address indicated by the ABS-
Bank Register and the Memory Address
Register (SPO).
System Verification and Troubleshooting
Table 3-2. Maintenance Panel Switches and Lamps (Continued)
I---l------~--------I---------'-------
--------'---------1
IPanell
Panel Marking
i
Use
I
1
Row
1 1 1
1 1 I I
----1- ---- ----- --- 1-----.------ -- ------.---.-- ---_.- - ---·------1
16
1
MEMORY STORE
1
When this switch is pressed, the folIow-I
1
(spring-return ing takes place.
I
1
switch)
1
1
The Memory Address Register (SPO) is
incremented or decremented by 1 if one
of the ADDRESS CONTROL switches is at
ENABLE. A carry from SPO does not en-
ter the ABS-Bank Register.
16
16
16
16
BREAKPOINT
READ ENABLE/
INHIBIT
(bi stable
switch)
BREAKPOINT
w"RITE ENABLE/
INHIBIT
(bistable
sw itch)
EXECUTE SW
RGTR (spring-
return switch)
EXECUTE SINGLE
INSTR (spr ing-
return switch)
In the ENABLE position,this switch halts
the CPU when a 16-bit word read from
memory is the same as the word in the
SWITCH REGISTER (0:15) switches.
In the ENABLE position,this switch halts
the CPU when memory storage takes place
at an address which is in the SWITCH
REGISTER B14, B15, and (0:15) switches.
When this switch is pressed, the CPU
executes the instruction in the SWITCH
REGISTER (0:15) switches. The P Register
contents do not change when the instr ue-
tion is performed unless the instruction
is a branch type; in this case, the P
Register receives the target address if
the branch condition is met. If a stack
operation is performed, stack operation
B should be NOP. (That is, positions 10
through 15 of the SWITCH REGISTER must
conta in ze ros.
When this switch is pressed, the in-
struction indicated by the P Register is
executed. The P Register is incremented
by 1, or it is loaded with a target ad-
dress if the instruction is a branch
type and the branch condition is met.
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