Paired relocatable terms
An expression can be absolute even though it contains relocatable terms, if all the relocatable terms are paired. The pairing of relocatable terms cancels the effect of relocation.
The assembler reduces paired terms to single absolute terms in
the intermediate stages of evaluation. The assembler considers relocatable
terms as paired under the following conditions:
- The paired terms must have the same relocatability attribute.
- The paired terms must have opposite signs after all unary operators are resolved. In an expression, the paired terms do not have to be contiguous (that is, other terms can come between the paired terms).
The following examples show absolute expressions.
A
is
an absolute term; X
and Y
are relocatable terms
with the same relocatability:
A-Y+X
A
A*A
X-Y+A
(*+*)-(*+*)
*-*
A reference to the location counter must be paired with another
relocatable term from the same control section; that is, with the
same relocatability. For example:
*-Y