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Cycle Time/High-speed Processing Section 6-1
ground execution so that no more than one instruction is executed at
the same time.
3. If an instruction for which background execution has been specified is ex-
ecuted, execution will only be started in the cycle in which the execution
condition was met and execution will not be completed in the same cycle.
4. When background execution is started, the Communications Port Enabled
Flag for that port will be turned OFF.
5. Background execution will be continued over several cycles.
6. When processing has been completed, the Communications Port Enabled
Flag for that port will be turned ON. This will enable another instruction to
be executed in the background.
Applicable Instructions
Background processing will not be performed for the following instructions
when they are used in function blocks. They will be executed using normal
processing.
■ Table Data Processing Instructions
■ Text String Processing Instructions
■ Data Shift Instructions
Differences between Instructions Executed Normally and in the Background
The differences between normal instruction execution and execution in the
background are listed below.
■ Outputting to Index Registers (IR)
If MAX(182) or MIN(183) is executed to output the I/O memory map address
of the word containing the minimum or maximum value to an index register,
Instruction Mnemonic
DATA SEARCH SRCH
SWAP BYTES SWAP
FIND MAXIMUM MAX
FIND MINIMUM MIN
SUM SUM
FRAME CHECKSUM FCS
Instruction Mnemonic
MOVE STRING MOV$
CONCATENATE STRING +$
GET STRING LEFT LEFT$
GET STRING RIGHT RIGHT$
GET STRING MIDDLE MID$
FIND IN STRING FIND$
STRING LENGTH LEN$
REPLACE IN STRING RPLC$
DELETE STRING DEL$
EXCHANGE STRING XCHG$
CLEAR STRING CLR$
INSERT INTO STRING INS$
Instruction Mnemonic
ASYNCHRONOUS SHIFT REGISTER ASFT
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