# /* DR-11a driver for timer version 1: Copies data from register to user space. A verified 16 bit number is returned as 2 bytes. */ #include "../../h/param.h" #include "../../h/conf.h" #include "../../h/user.h" #define DRADDR 0167770 struct { char lobyte; char hibyte; }; struct { int drcsr; int drwritereg; int drreadreg; }; timerread () { int i; while ((i = DRADDR -> drreadreg) != (DRADDR -> drreadreg)); if (passc (i.lobyte) >= 0) passc (i.hibyte); }