Short PDP-8 Memory Test...

I recently acquired another PDP-8/E and wanted to test basic CPU functions and memory before I added peripherals. There are some available short "memory tests" online, but most don't have have the flexibility to test multiple data patterns by design. The test below does a classic checkerboard type test - and permits easy modification of the data pattern used in testing. --- # Easy to enter, short memory test for PDP-8 systems # prior to adding peripheral equipment. # by Lyle Bickley # # Location 21 initially contains a zero. Therefore the # memory test is 0000 and 7777 in alternate locations. # Changing this location to 7070 will test 7070 and # 0707 in alternate locations. Changing it to 5252 will # test 5252 and 2525, etc. 0000 7300 CLA CLL 0001 1022 TAD 22 0002 3023 DCA 23 0003 7300 CLA CLL 0004 1021 TAD 21 0005 7040 CMA 0006 3021 DCA 21 0007 1021 TAD 21 0010 3423 DCA I 23 0011 1021 TAD 21 0012 7041 CMA IAC 0013 1423 TAD I 23 0014 7440 SZA 0015 7402 HLT (ERROR - AC SHOWS FAIL) 0016 2023 ISZ 23 0017 5003 JMP 3 (INC LOCATION AND LOOP) 0020 5000 JMP 0 (START OVER) 0021 0000 (0=ALT 7777 AND 0000) 0022 0025 (LOCATION TO START TEST - MAKE ODD) 0023 0000 (LOCATION BEING TESTED) --- Cheers, Lyle -- 73 NM6Y Bickley Consulting West https://bickleywest.com "Black holes are where God is dividing by zero"