UPD77018A NEC, UPD77018A Datasheet - Page 16

• Manufacturer Part Number: UPD77018A
• Description: 16 bits/ Fixed-point Digital Signal Processor
• Manufacturer: NEC

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with written back to general registers. Pipeline processing actualizes programming without delay time to execute
instructions and write back data. Three successive instructions and their processing timing are shown below.
2.1.2 Instructions with Delay
2. FUNCTIONS
2.1 Pipeline Processing
2.1.1 Outline
This section describes the PD77018A pipeline processing.
The PD77018A basic operations are executed in following 3-stage pipeline.
(1) instruction fetch; if
(2) Instruction decoding; id
(3) execution; ex
When the PD77018A operates a result of a instruction just executed before, the data is input to ALU in parallel
The following instructions have delay time in execution.
(1) Instructions to control interrupt
(2) Inter-register transfer instructions and immediate data set instructions
2 instruction cycles have been taken between instruction fetch and execution.
When data is set in data pointer, it needs 2 instruction cycles before the data is valid.
if1
1 instruction cycle
id1
if2
Pipeline Processing Timing
ex1
id2
if3
ex2
id3
ex3
PD77018A, 77019