PiDP‐10 tests: address stop and break

These switches prove a way to set breakpoints. The breakpoint address is taken from the address switches, and the type of breakpoint - read, write, or execute - is taken from the address condition switches.

A stop means the processor will halt immediately when the breakpoint contitions are met, and then an operator can examine the machine state through the panel. A break means an interrupt will be raised, and then software can handle the breakpoint.

Preparation

Put all switches in the up (off) position.
Start the emulator.
Enter the test program:

d 42 JRST 42
d 1000 CONO APR,40001
d 1001 CONO PI,12300
d 1002 MOVE 2000
d 1003 MOVEM 4000
d 1004 JRST 1000

Address stop at read

Enter 1000 in address switches.
Push START.
⟹ Program should start running.
⟹ RUN light should be on.
Enter 2000 in address switches.
Push ADR STOP.
Push ADDRESS CONDITION - INST FETCH and ADDRESS CONDITION - WRITE.
⟹ Program should keep running.
Release ADDRESS CONDITION - INST FETCH and ADDRESS CONDITION - WRITE.
Push ADDRESS CONDITION - DATA FETCH.
⟹ Program should stop running.
⟹ RUN light should turn off.
⟹ MEMORY STOP light should turn on.
⟹ Address lights should read 2000.
Release ADDRESS CONDITION - DATA FETCH.
Push CONT.
⟹ Program should resume.
⟹ RUN light should turn on.
⟹ MEMORY STOP light should turn off.

Address stop at write

Enter 4000 in address switches.
Push ADR STOP.
Push ADDRESS CONDITION - INST FETCH and ADDRESS CONDITION - DATA FETCH.
⟹ Program should keep running.
Release ADDRESS CONDITION - INST FETCH and ADDRESS CONDITION - DATA FETCH.
Push ADDRESS CONDITION - WRITE.
⟹ Program should stop running.
⟹ RUN light should turn off.
⟹ MEMORY STOP light should turn on.
⟹ Address lights should read 4000.
Release ADDRESS CONDITION - WRITE.
Push CONT.
⟹ Program should resume.
⟹ RUN light should turn on.
⟹ MEMORY STOP light should turn off.

Address stop at instruction fetch

Enter 1000 in address switches.
Push ADR STOP.
Push ADDRESS CONDITION - WRITE and ADDRESS CONDITION - DATA FETCH.
⟹ Program should keep running.
Release ADDRESS CONDITION - WRITE and ADDRESS CONDITION - DATA FETCH.
Push ADDRESS CONDITION - INST FETCH.
⟹ Program should stop running.
⟹ RUN light should turn off.
⟹ MEMORY STOP light should turn on.
⟹ Address lights should read 1000.
Release ADDRESS CONDITION - INST FETCH.
Push CONT.
⟹ Program should resume.
⟹ RUN light should turn on.
⟹ MEMORY STOP light should turn off.

Address break at read

Enter 1000 in address switches.
Push START.
⟹ Program should start running.
⟹ RUN light should be on.
⟹ PI ON light should be on.
⟹ PI ACTIVE 1 should be on, 2-7 should be off.
Enter 2000 in address switches.
Push ADR BREAK.
Push ADDRESS CONDITION - INST FETCH and ADDRESS CONDITION - WRITE.
⟹ Program should keep running.
Release ADDRESS CONDITION - INST FETCH and ADDRESS CONDITION - WRITE.
Push ADDRESS CONDITION - DATA FETCH.
⟹ Program should keep running.
⟹ PROGRAM COUNTER should read 42.
⟹ IOB PI REQUEST 1 should turn on, 2-7 should be off.
⟹ PI IN PROGRESS 1 should turn on, 2-7 should be off.
Release ADDRESS CONDITION - DATA FETCH.

Address break at write

Push STOP.
⟹ Program should stop running.
Enter 1000 in address switches.
Push START.
⟹ Program should start running.
⟹ RUN light should be on.
⟹ PI ON light should be on.
⟹ PI IN PROGRESS and IOB PI REQUEST should all turn off.
⟹ PI ACTIVE 1 should be on, 2-7 should be off.
Enter 4000 in address switches.
Push ADR BREAK.
Push ADDRESS CONDITION - INST FETCH and ADDRESS CONDITION - DATA FETCH.
⟹ Program should keep running.
Release ADDRESS CONDITION - INST FETCH and ADDRESS CONDITION - DATA FETCH.
Push ADDRESS CONDITION - WRITE.
⟹ Program should keep running.
⟹ PROGRAM COUNTER should read 42.
Release ADDRESS CONDITION - WRITE.

Address break at instruction fetch

Push STOP.
⟹ Program should stop running.
Enter 1000 in address switches.
Push START.
⟹ Program should start running.
⟹ RUN light should be on.
⟹ PI ON light should be on.
⟹ PI IN PROGRESS and IOB PI REQUEST should all turn off.
⟹ PI ACTIVE 1 should be on, 2-7 should be off.
Push ADR BREAK.
Push ADDRESS CONDITION - WRITE and ADDRESS CONDITION - DATA FETCH.
⟹ Program should keep running.
Release ADDRESS CONDITION - WRITE and ADDRESS CONDITION - DATA FETCH.
Push ADDRESS CONDITION - INST FETCH.
⟹ Program should keep running.
⟹ PROGRAM COUNTER should read 42.
Release ADDRESS CONDITION - INST FETCH.