- Fri Sep 15, 2017 12:47 pm
#70018
Where my mind went ... some time back (we won't discuss dates) I was the programmer on a DEC PDP-7 - had a 8k core memory, the OS (which used 6k of the 8k) idled in a loop of 10 nop's with a jmp -10 at the end. I experimented with telling the system to read in from paper tape what was in effect a subroutine. The last line of code on the tape was a 'call progstart'.
so we had: nop, nop, nop, nop, sub(); nop, nop, nop, nop, nop, jmp -10
programstart just compiled any keystrokes and if they matched a case it continued on into the sub-program, if not then back to the wait loop. When the program finished it put a "nop" over the sub() in the loop.
Montana Large Aperture Seismic Array (12 yrs)