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3.5
Reducing Instruction Processing Time
Subset processing
Subset processing is used to place limits on bit devices used by basic instructions and application instructions in order to
increase processing speed.
However, the instruction symbol does not change.
To shorten scans, run instructions under the conditions indicated below.
Conditions which each device must meet for subset processing
■When using word data
Device
Bit device
Word device
Constant
■When using double word data
Device
Bit device
Word device
Constant
■When using bit data
Device
Bit device
Word device
*1 Only for Universal model QCPU
*2 Valid only for the multiple CPU high speed transmission area (from U3En\G10000)
(Excluding the case that indexing is executed for the head I/O number of the CPU module (U3En\G10000))
*3 Applies only to Universal model QCPU and LCPU.
*4 Applies only to Universal model QCPU (excluding Q00UJCPU) and LCPU.
3 CONFIGURATION OF INSTRUCTIONS
108
3.5 Reducing Instruction Processing Time
Condition
• Designates a bit device number in a factor of 16.
• Only K4 can be designated for digit designation.
• Does not perform indexing.
• Internal user device
*4
• File register (R, ZR
)
*1*2
• Multiple CPU shared device
• Index register (Z) / Standard device register (Z)
• No limitations
Condition
• Designates a bit device number in a factor of 16.
• Only K8 can be designated for digit designation.
• Does not perform indexing.
• Internal user device
*4
• File register (R, ZR
)
*1*2
• Multiple CPU shared device
• Index register (Z) / Standard device register (Z)
• No limitations
Condition
• Internal user device (indexing possible)
• Bit specification of internal user device
• Bit specification of file register (R, ZR
• Bit specification of multiple CPU shared device
*3
*3
*4
)
*1*2
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