20 Dec
2016
20 Dec
'16
3:33 a.m.
From: "Steve Johnson"
The number on the left is a PDP-11 address, probably
for some kind of
control register.
It's the Processor Status Word, which contained the CPU's hardware priority
level, condition codes, etc.
That's a construction that's left over from
B.
I wonder why it was written as "0177776->integ", rather than
"*017776"?
Probably the former allowed the C compiler to work out what size the operand
was. (BTW, 'integ' was declared in a structure declaration as follows:
struct {
int integ;
};
(Did the code looked at actually say "0177776->int"? The compiler might have
barfed on a reserved keyword being used like that.)
Noel