Pipeline Execution of Instruction Types
Pipeline
4-32
SPRU733
4.2.14 MPYSPDP Instruction
The MPYSPDP instruction uses the E1 through E7 phases of the pipeline to
complete its operations (see Table 4
−
16).
src1
is read on E1 and E2. The lower
32 bits of
src2
are read on E1, and the upper 32 bits of
src2
are read on E2.
The lower 32 bits of the result are written on E6, and the upper 32 bits of the
result are written on E7. The MPYSPDP instruction is executed on the .M unit.
The functional unit latency for the MPYSPDP instruction is 3. Figure 4
−
26
shows the fetch, decode, and execute phases of the pipeline that the
MPYSPDP instruction uses.
Table 4
−
16. MPYSPDP Instruction Execution
Pipeline Stage
E1
E2
E3
E4
E5
E6
E7
Read
src1
src2_l
src1
src2_h
Written
dst_l
dst_h
Unit in use
.M
.M
Figure 4
−
26. MPYSPDP Instruction Phases
PG
PS
PW
PR
DP
DC
E1
E2
E3
E4
E5
E6
E7
6 delay slots