Chapter 8 Writing Source Statements
136 Location Counter
8.6 Location CounterThe assembler contains an variable for counting addresses of instructions. This variable is called the
location counter. Each time the assembler converts an instruction to machine language, it increments
the location counter by the number of words in that instruction.
Location counter values are first set during linking for each section defined by the section directive, so
location counter values during assembly will not necessarily match the addresses assigned to
instructions during execution. Location counter values during execution will be offset values from the
start of each section.
The address of the current instruction can be coded as an asterisk (*). This asterisk is called the self-
reference address symbol. By using a self-reference address symbol in the operand field of a source
statement, you can reference the address assigned to that statement during execution.