[TUHS] nm on Third Edition .o files?

Noel Chiappa jnc at mercury.lcs.mit.edu
Tue Dec 20 07:33:08 AEST 2016


    > 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


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