Tomasulo's algorithm

Tomasulo's algorithm is a <a href="/facts/Computer_architecture/tHtwxgR2">computer architecture</a> hardware <a href="/facts/Algorithm/fnl5NmRt">algorithm</a> for dynamic scheduling of instructions that allows <a href="/facts/Out-of-order_execution/bM0dQM8m">out-of-order execution</a> and enables more efficient use of multiple execution units. It was developed by <a href="/facts/Robert_Tomasulo/E05zkQQh">Robert Tomasulo</a> at <a href="/facts/IBM/QszA7nwd">IBM</a> in 1967 and was first implemented in the <a href="/facts/IBM_System%2f360_Model_91/Yo9gocm4">IBM System/360 Model 91</a>’s <a href="/facts/Floating_point_unit/XWTW2AbF">floating point unit</a>.
The major innovations of Tomasulo’s algorithm include <a href="/facts/Register_renaming/m1HXzC5x">register renaming</a> in hardware, <a href="/facts/Reservation_station/K30jCKs0">reservation stations</a> for all execution units, and a common data bus (CDB) on which computed values broadcast to all reservation stations that may need them. These developments allow for improved <a href="/facts/Parallel_computing/nQzcpzQt">parallel execution</a> of instructions that would otherwise stall under the use of <a href="/facts/Scoreboarding/oAz1Ws6q">scoreboarding</a> or other earlier algorithms.
<a href="/facts/Robert_Tomasulo/E05zkQQh">Robert Tomasulo</a> received the <a href="/facts/Eckert%25E2%2580%2593Mauchly_Award/btcqGKSr">Eckert–Mauchly Award</a> in 1997 for his work on the algorithm.

Tomasulo's algorithm open-in-new

Tomasulo's algorithm