302 Part 2 ½ Regions of Computer Space Section 3 ½ Concurrency: Single-Processor System
|
LOOP |
MD |
F0, |
Ai |
|
AD |
F0, |
Bi |
|
|
LD |
F2 |
Ci |
|
|
SDR |
F2 |
F0 |
|
|
MDR |
F2 |
F6 |
|
|
AD2 |
F2 |
Ci |
|
|
STD |
F2 |
Ci |
|
|
BXH |
i, |
-1, 0 LOOP |
Without the CDB one iteration of the loop would use 17 cycles, allowing 4 per MD, 3 per AD and nothing for LD or STD. With the CDB one iteration requires 11 cycles. For this kind of code the CDB improves performance by about one third.
References
Tomasulo [1967]; Anderson, Earle, Goldschmidt, and Powers [1967]; Anderson, Sparacio, and Tomasulo [1967].