Operations Occurring During Fixed-Point Pipeline Phases - Texas Instruments TMS320C6000 Series Reference Manual

Table 5–1. Operations Occurring During Fixed-Point Pipeline Phases
Stage Phase
Program Program address
fetch generate
Program address
send
Program wait
Program data
receive
Program Dispatch
decode
Decode
Execute Execute 1
Execute 2
Execute 3
Execute 4
Execute 5
† This assumes that the conditions for the instructions are evaluated as true. If the condition is evaluated as false, the instruction
does not write any results or have any pipeline operation after E1.
Table 5–1 summarizes the pipeline phases and what happens in each.
Symbol During This Phase
PG The address of the fetch packet is determined.
PS The address of the fetch packet is sent to
memory.
PW A program memory access is performed.
PR The fetch packet is at the CPU boundary.
DP The next execute packet in the fetch packet is de-
termined and sent to the appropriate functional
units to be decoded.
DC Instructions are decoded in functional units.
E1 For all instruction types, the conditions for the
instructions are evaluated and operands are
read.
For load and store instructions, address genera-
tion is performed and address modifications are
written to a register file.
For branch instructions, branch fetch packet in
PG phase is affected.
For single-cycle instructions, results are written
to a register file.
E2 For load instructions, the address is sent to
memory. For store instructions, the address and
data are sent to memory.
Single-cycle instructions that saturate results set
the SAT bit in the control status register (CSR) if
saturation occurs.
For multiply instructions, results are written to a
register file.
E3 Data memory accesses are performed. Any mul-
tiply instruction that saturates results sets the
SAT bit in the control status register (CSR) if sat-
uration occurs.
E4 For load instructions, data is brought to the CPU
boundary.
E5 For load instructions, data is written into a regis-
†
ter.
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†
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TMS320C62x Pipeline
Pipeline Operation Overview
Instruction
Type
Completed
Single cycle
Multiply
Store
Load
5-7