@ sign in assembler?

Question

I am doing an assignment for an information systems class and the professor decided to use psuedo-assembler. He used the

@

in

SUB @106, -2(104), 110

What does that symbol mean?

Answer 1

In DEC's assembly languages (PDP-11, VAX) @ means indirect addressing mode, i.e. an extra level of indirection.

In your case, @106 means that the address of the operand is taken from the address 106.