IXh <- (nn+1), IXl <- (nn)
The contents of the address (nn) are loaded to the low-order portion of Index Register IX, and the contents of the next highest memory address (nn + 1) are loaded to the high-order portion of IX. The first n operand after the op code is the low-order byte of nn.
If address $6666 contains $92 and address $6667 contains $DA, then upon execution of
Index Register IX will contain $DA92.