Loop: (code.....) leax -1,x bne loop You can use X or Y, but not S or U for the loop. On 4/15/2014 6:19 AM, Mark McDougall wrote: > How would one write a (tight) loop, say a few thousand iterations in > 6809 assembler? Can it be done with the X/Y registers? D? Or do I need > a memory variable? It's for a delay... > > Regards, >