Paul Koning wrote: > On the "one word clear", I missed a detail. I pointed out you get to > initialize the registers. You can also initiate one memory word. In other > words: choose two words in memory, and registers contents, such that > execution will give you a memory full of zeroes and a halted machine.
OK, *now* the problem has a clear solution: 1) Write 000000 into memory word 015720; 2) Write 015720 [ MOV @-(PC),(R0)+ ] into the last word of system RAM; 3) Clear R0; 4) Jump to the last word of RAM where you wrote the 015720 instruction. This solution does require that the system RAM be of certain minimum size. Assuming power-of-2 sizes only, the machine must have at least 8 KiB of RAM, otherwise location 015720 does not exist. What was the smallest RAM configuration on PDP-11? M~
