Index Register (Z)/Standard Device Resister (Z); Index Register (Z) - Mitsubishi Electric Q01UCPU User Manual

4.6

Index Register (Z)/Standard Device Resister (Z)

4.6.1

Index register (Z)

The index register is used for indirect specification (index modification) in sequence programs.
Index modification uses one point of the index register.
The index register has 20 points (Z0 to Z19).
(1) Bit structure of the index register
(a) Bit structure and read/write unit
One point of the index register consists of 16 bits, and data can be read or written in units of 16 bits.
Index register data are handled as signed data.
In the case of the hexadecimal notation, 0000
represents a sign bit, decimal values that can be specified are -32768 to 32767. (When using T, TS, or C device, specify the
values within the range of -16384 to 16383.)
(b) When using the index register for a 32-bit instruction
The processing target is Zn and Zn+1.
The lower 16 bits correspond to the specified index register number (Zn), and the higher 16 bits correspond to
the specified index register number + 1.
When Z2 is specified in the DMOV instruction, Z2 represents the lower 16 bits and Z3 represents the
Ex.
higher 16 bits. (The most significant bit in a 32-bit structure is a sign bit.)
X0
MOVP
SM400
BCD D0Z0 K4Y30
b15
Zn
Most significant bit represents a sign bit.
to FFFF
H
DMOV
K5 Z0
Specify the index register
by one point (16 bits).
to
can be stored. However, because the most significant bit
H
D0 Z2
Processing target:
Z3 Z2
Upper 16 bits Lower 16 bits
CHAPTER 4 DEVICES
b0
4
383