Dependency Graph Of If-Then-Else Code (Unrolled); Drawing A Dependency Graph - Texas Instruments TMS320C6000 Programmer's Manual

Loop Unrolling
6.9.3

Drawing a Dependency Graph

Figure 6–18. Dependency Graph of If-Then-Else Code (Unrolled)
1
ADD
sumi
1
6-96
Although there are numerous ways to split the dependency graph, the main
goal is to achieve a minimum iteration interval of 3 and meet these conditions:
You cannot have more than nine non-.M instructions on either side.
Only three non-.M instructions can execute per cycle.
Figure 6–18 shows the dependency graph for the unrolled if-then-else code.
Nine instructions are on the A side, and seven instructions are on the B side.
AND
condi
1
1
MVK
!(!(condi)
1
CMPEQ
LDH
ifi
ai
1
1
5
SUB
sumi
1
1 1
A side
SHL
maski+1 condi+ 1
1
1
SHL
maski
!(!(condi+1))
LDH
ifi+1
ai+1
5
5
1
ADD
sumi+1
1
1
B side
AND
1
MVK
ADD
1
CMPEQ
cntr
1
1
Loop
5
SUB
sumi+1
1
1
1
B