A Circuit for Identifying Oldest Ready Instructions in Reservation Stations
Journal
2020 43rd International Convention on Information, Communication and Electronic Technology (MIPRO)
Date Issued
2020-09-28
Author(s)
DOI
10.23919/mipro48935.2020.9245125
Abstract
Microprocessors use reservation stations to host instructions that are waiting to be sent to the execution units. Reservation stations may include selection logic configured to select oldest ready instructions for execution. Conventional selection logic uses age matrices to track relative age among instructions. In this paper, we propose an alternative circuit for tracking the relative age among instructions in reservation stations. The proposed selection logic uses wrap bits and reorder buffer indexes to track relative age among instructions. We compare the proposed selection logic with the conventional selection logic and discuss advantages.