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4.2.12
Data register (D)
The data register (D) is a memory in which numeric data (-32768 to 32767, or 0000
stored.
(1) Bit structure of the data register
(a) Bit structure and read/write unit
One point of the data register consists of 16 bits, and data can be read or written in units of 16 bits.
Data 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.
(b) When using a 32-bit instruction for the data register
For a 32-bit instruction, two consecutive points of the data register (D
processing.
The lower 16 bits correspond to the data register number (Dn) specified in the sequence program, and the
higher 16 bits correspond to the specified data register number + 1.
When D12 is specified in the DMOV instruction, D12 represents the lower 16 bits and D13 represents the
Ex.
higher 16 bits.
Data of -2147483648 to 2147483647 or 00000000
data register. (The most significant bit in a 32-bit structure is a sign bit.)
(2) Retention of stored data
The data stored in the data register are held until other different data are stored.
Note that the stored data are initialized when the CPU module is powered off or reset.
b15
Dn
Most significant bit represents a sign bit.
to FFFF
H
DMOV
K500000 D12
to
b0
can be stored. However, because the most significant bit
H
and D
n
n+1
Processing target: D12, D13
D13
D12
Upper 16 bits Lower 16 bits
to FFFFFFFF
can be stored in a two-point area of the
H
H
CHAPTER 4 DEVICES
to FFFF
) can be
H
H
) are the target of the
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4
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