Справочник Пользователя для Mitsubishi Electronics QCPU

Скачать
Страница из 1204
3-2
3.1  
Configuration of Instructions
Most CPU module instructions consist of an instruction part and a device part.
Each part is used for the following purpose:
• Instruction part ...... indicates the function of the instruction.
• Device part ............ indicates the data that is to be used with the instruction.
The device part is classified into source data, destination data, and number of devices.
(1) Source (S)
(a) Source is the data used for operations.
(b) The following source types are available, depending on the designated device:
 • Constant ............................................... Designates a numeric value to be used in the 
operation.
This is set when the program is created, and 
cannot be changed during the execution of 
the program.
Constants should be indexed when used as 
variable data.
 • Bit devices and word devices ............... Designates the device that stores the data to 
be used in the operation.
Data must be stored in the designated 
device until the operation is executed.
By changing the data stored in a designated 
device during program execution, the data to 
be used in the instruction can be changed.
(2) Destination (D)
(a) The destination stores the data after the operation has been conducted. However,  
some instructions require storing the data to be used in an operation at the destination 
prior to the operation execution.
 An addition instruction involving BIN 16-bit data
(b) A device for the data storage must always be set to the destination.
(3) Number of devices and number of transfers (n)
(a) The number of devices and number of transfers designate the numbers of devices and 
transfers used by instructions involving multiple devices.
 Block transfer instruction
(b) The number of devices or number of transfers can be set between 0 and 32767.  
However, if the number is 0, the instruction will be a no-operation instruction.
Example
D
S2
S1
+
D
S
+
Stores only the 
operat
ion results.
Stores the data needed for operation  
before
 the actual operation.
Example
n
D
S
BMOV
Designates the number of transfers 
use
d by a BMOV instruction