norman@cs.purdue.EDU (Victor Todd Norman) (03/28/90)
I have noticed something that I don't believe appears anywhere in any documentation. Here's the situation: I have one high priority process running on my T414B. This process looks at the special "register save area" (see p. 79 of Compiler Writers' Guide), and sees NotProcess.p (0x80000000) in WdescIntSaveLoc (thus, no low priority process was interrupted). Then, the process executes an IN instruction, and then looks again at WdescIntSaveLoc, and now the value has been changed to 0x80000001 (the low bit has been set). I supposed there is a good reason for this?, or is my hardware acting funny... I have noticed that this only happens if the process doing the IN (or OUT) is running at high priority. Victor Norman