A label declaration is an identifier followed by a ":". A label is way of naming an address of a VAX instruction or of data.
e.g.
Start: ; declare the label Start
We can then use the label anywhere we would normally use an address.
eg.
brb Start ; Note no colon is used in references to labels
The BSD numeric labels 0 through 9 are also recognised by the assembler. Multiple numeric labels using the same number may exist in a program at one time. These are referenced in instructions, by appending a "b" to the number to refer to the previous label using that number, or by appending an "f" to refer to the next label using that number. eg.
1: ...
movl R0, R1
blss 2f ;branches forwards to the next label 2
bgtr 1f ;branches forwards to the next label 1
bequ 1b ;branches Backwards to the previous label 1
2: ...
1: ...
Nb.
The assembler translates numeric labels into the form Ln,
where n is a unique number selected to make the label unique.
