NEC PD17062 User Manual
Page 57
57
µ
PD17062
8.5 INDEX REGISTER (IX) AND DATA MEMORY ROW ADDRESS POINTER (MP)
8.5.1 Configuration of Index Register and Data Memory Row Address Pointer
As shown in Fig. 8-1, the index register consists of 11 bits, including the three low-order bits, of 7AH (IXH)
of the system register, 7BH, and 7CH (IXM, IXL). The index register is used to indirectly specify a data memory
address.
The data memory row address pointer consists of 7 bits, including the three low-order bits of 7AH (MPH)
and 7BH (MPL).
This means that the seven high-order bits of the index register and data memory row address pointer are
shared.
The four high-order bits of the index register, i.e., the four high-order bits of the data memory row address
pointer (7AH b
2
-b
0
, 7BH b
3
), of
µ
PD17062 are fixed at 0.