Assembling Code for Machines with Span-Dependent Instructions
Many modern computers contain instructions
whose lengths depend on the distance from a given 
instance of such an instruction to the operand of that
instruction.  This paper considers the problem 
of minimizing the lengths of programs for such machines.
 An efficient solution is presented for the 
case in which the operand of every such "span-dependent"
instruction is either a label or an assembly-time 
expression of a certain restricted form.If this restriction
is relaxed by allowing these operands to 
be more general assembly-time expressions, then
the problem is shown to be NP-complete.
CACM April, 1978
Szymanski, T.G.
