PDP-8 diagnostic tests
scott.l.baker at gmail.com
Tue Aug 23 14:31:42 CDT 2016
I have written a PDP-8 VHDL model and I have it running in an FPGA
At this time it has passed a basic DEC diagnostic instruction test but
I found some interesting things when getting that instruction test to pass.
The following segment of code implies that IAC instruction affects the Link
1797 /GROUP 1 OPERATE TEST 33
1798 02626 7300 CLA CLL /AC=0000 LINK=0
1799 02627 1053 TAD K2525 /AC=2525
1800 02630 7261 CLA CMA CML IAC /TEST COMBINATION
1801 02631 7420 SNL
1802 02632 7430 SZL
1803 02633 7402 HLT /CLA CMA CML IAC FAILED, AC SHOULD
1804 /BE 0000, LINK SHOULD BE ZERO
but the PDP-8 Handbook ; DEC copyright 1966; page 14
says nothing about the Link bit being affected by the IAC instruction.
The simh PDP-8 simulator also shows that L is affected by IAC.
If I change this test line from
1800 02630 7261 CLA CMA CML IAC /TEST COMBINATION << link=0
1800 02630 7261 CLA CMA CML /TEST COMBINATION << link=1
Can anyone point me to:
1) DEC documentation which more fully describes all the instruction set (in
more detail than the PDP-8 handbook)
2) Some more instruction tests in assembler source code format. I have
found lots of binary files but I would prefer assembler source code format.
I am using a pal compatible cross assembler.
Thanks and Regards,
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