Date   : Fri, 21 Dec 1984 08:08:00 PST
From   : ACB.TYM@OFFICE-2.ARPA
Subject: Technical trivia

(everybody else puts a dummy line here. Why not?)

Speaking of technical data! I just spent most of a day discovering that BDS C 
uses the interrupt vector at location x'30' (RST 6).  I have often thought of 
using RST instructions for linkages in self relocating code BUT... I fear the 
impact on some unsuspecting user with some hardware interrupt configuration or 
some special storage locations (Some code uses the high end of interrupt vector
7 (DDT's RST location) already.  I read both CP/M documentation and BDS C 
documentation and find that in the CP/M documentation RST 6 locations are 
reserved and RST 7 is used by DDT.  I was a tad surprised to find that BDS C 
used RST 6.  Of course that is because I was using it (caught in the act!) 
although the use was unintentional (a bug!).