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ColdFire Core
MCF5272 ColdFire
®
Integrated Microprocessor User’s Manual, Rev. 3
2-2
Freescale Semiconductor
Figure 2-1. ColdFire Pipeline
2.1.1.1
Instruction Fetch Pipeline (IFP)
The IFP generates instruction addresses and fetches. Because the fetch and execution pipelines are
decoupled by a three longword FIFO buffer, the IFP can prefetch instructions before the OEP needs them,
minimizing stalls.
2.1.1.2
Operand Execution Pipeline (OEP)
The OEP is a two-stage pipeline featuring a traditional RISC datapath with a register file feeding an
arithmetic/logic unit (ALU). For simple register-to-register instructions, the first stage of the OEP
performs the instruction decode and fetching of the required register operands (OC), while the actual
instruction execution is performed in the second stage (EX).
For memory-to-register instructions, the instruction is effectively staged through the OEP twice in the
following way:
•
The instruction is decoded and the components of the operand address are selected (DS).
•
The operand address is generated using the execute engine (AG).
•
The memory operand is fetched while any register operand is simultaneously fetched (OC).
•
The instruction is executed (EX).
Instruction
Instruction
FIFO
Decode & Select,
Address
Data[31:0]
IAG
IC
IB
DSOC
AGEX
Address [31:0]
Instruction Buffer
Address
Generation
Fetch Cycle
Generation,
Execute
Operand Fetch
Operand
Execution
Pipeline
Instruction
Fetch
Pipeline