This weeks puzzle

Little Joe who loves C reads in many posts that a delay routine should be made in assembler and decides to make one.
He has a C function definition:
void Delay (unsigned short count);

He finds out correctly that "count" will be in R6 (MSB) and R7 (LSB) when "Delay" is called

so little Joe writes the following routine

Delay:
;; here 
loop: djnz r7,loop
      djnz r6,loop
      ret

Little Joe finds out that this works correctly in most cases, but fails for some values of "count". He then adds some code where ";;here" is and the code works in all cases

What code did little Joe add?

Erik

PS: the same measures should be taken every time there is a multibyte loop in asm.