If your assembler doesn't already have structured control-flow, e.g. _IF _ELSE _ENDIF _UNTIL _WHILE etc (not to be confused with conditional assembly)
then here's how to add it yourself for free, without needing access to the assembler's source code.
http://dkeenan.com/AddingStructuredControlFlowToAnyAssembler.htm
Structured control-flow eliminates the need for most explicit jumps, and the labels they jump to, and thereby makes your code more readable and maintainable.
-- Dave Keenan