Pipeline Execution of Instruction Types
Pipeline
4-14
SPRU733
Table 4
−
2. Execution Stage Length Description for Each Instruction Type (Continued)
Instruction Type
Execution
phases
ADDDP/SUBDP
MPYI
MPYID
MPYDP
E1
Read lower sources
and start computation
Read sources and
start computation
Read sources and
start computation
Read lower sources
and start computation
E2
Read upper sources
and continue
computation
Read sources and
continue computation
Read sources and
continue computation
Read lower
src1
and
upper
src2
and
continue computation
E3
Continue computation Read sources and
continue computation
Read sources and
continue computation
Read lower
src2
and
upper
src1
and
continue computation
E4
Continue computation Read sources and
continue computation
Read sources and
continue computation
Read upper sources
and continue
computation
E5
Continue computation Continue computation Continue computation Continue computation
E6
Compute the lower
results and write to
register
Continue computation Continue computation Continue computation
E7
Compute the upper
results and write to
register
Continue computation Continue computation Continue computation
E8
Continue computation Continue computation Continue computation
E9
Complete computa-
tion and write results
to register
Continue computation
and write lower
results to register
Continue computation
and write lower
results to register
E10
Complete computa-
tion and write upper
results to register
Complete computa-
tion and write upper
results to register
Delay slots
6
8
9
9
Functional
unit latency
2
4
4
4
Notes:
1) This table assumes that the condition for each instruction is evaluated as true. If the condition is evaluated as
false, the instruction does not write any results or have any pipeline operation after E1.
2)
NOP
is not shown and has no operation in any of the execution phases.