[TUHS] Maximum Array Sizes in 16 bit C

Hello all, I know that this isn't strictly a "UNIX history" question, but as I am working with historic UNIX and this list contains a great number of people who were instrumental in its development, I figured it would be appropriate to ask here. If there's a better place for these sorts of questions, please let me know. I'm trying to figure out how the array size limits are set in the 2.11BSD pcc compiler. I've looked through quite a bit of documentation but I don't see anything that describes this. In theory on a 16 bit system I would think that the maximum array size would be 64K, but the actual limit that I found through trial and error is (2^15)-1. Declaring an array that is too large results in an error of "Constant required", which is being produced by c01.c in conexp(). https://www.tuhs.org/cgi-bin/utree.pl?file=2.11BSD/src/lib/ccom/c01.c I did quite a bit of searching through the source but I was not able to determine where this limit is being set. This is where my usual tools fall apart. Normally since I have the source I would compile the program I want with debugging turned on, and then do a backtrace so that I could see how we got to conexp(). But as far as I can tell I can't get a backtrace, since there is no option for debugging information in pcc; adb can only tell me where a process stopped. I would appreciate any enlightenment or pointers to other documentation. Thanks in advance! -Henry