Quantum computing promises an effective way to solve targeted problems that are classically intractable. Among them, quantum computers built with superconducting qubits are considered one of the most advanced technologies, but they suffer from short coherence times. This can get exaggerated when they are controlled directly by general-purpose host machines, which leads to the loss of quantum information. To mitigate this, we need quantum control processors (QCPs) positioned between quantum processing units and host machines to reduce latencies. However, existing QCPs are built on top of designs with no or inefficient scalability, requiring a large number of instructions when scaling to more qubits. In addition, interactions between current QCPs and host machines require frequent data transmissions and offline computations to obtain final results, which limits the performance of quantum computers. In this paper, we propose a QCP called HiSEP-Q featuring a novel quantum instruction set architecture (QISA) and its microarchitecture implementation. For efficient control, we utilize mixed-type addressing modes and mixed-length instructions in HiSEP-Q, which provides an efficient way to concurrently address more than 100 qubits. Further, for efficient read-out and analysis, we develop a novel onboard accumulation and sorting unit, which eliminates the data transmission of raw data between the QCPs and host machines and enables real-time result processing. Compared to the state-of-the-art, our proposed QISA achieves at least 62% and 28% improvements in encoding efficiency with real and synthetic quantum circuits, respectively. We also validate the microarchitecture on a field-programmable gate array, which exhibits low power and resource consumption. Both hardware and ISA evaluations demonstrate that HiSEP-Q features high scalability and efficiency toward the number of controlled qubits.

翻译：量子计算为解决经典计算难以处理的目标问题提供了一种有效途径。其中，基于超导量子比特构建的量子计算机被视为最先进的技术之一，但其存在相干时间短的局限。当量子比特直接由通用宿主机控制时，这一缺陷会进一步放大，导致量子信息丢失。为缓解这一问题，我们需要在量子处理单元与宿主机之间部署量子控制处理器（QCP）以降低延迟。然而，现有QCP的架构设计缺乏可扩展性或效率低下，在扩展至更多量子比特时需要大量指令。此外，当前QCP与宿主机的交互需要频繁的数据传输和离线计算才能获得最终结果，这限制了量子计算机的性能。本文提出了一种名为HiSEP-Q的QCP，其核心是一种新型量子指令集架构（QISA）及其微架构实现。为实现高效控制，我们在HiSEP-Q中采用了混合型寻址模式和混合长度指令，从而能够高效地同时寻址超过100个量子比特。此外，为提升读出与分析效率，我们开发了一种新型板载累加与排序单元，消除了QCP与宿主机之间的原始数据传输需求，并实现了实时结果处理。与现有技术相比，我们提出的QISA在真实量子电路和合成量子电路上的编码效率分别提升了至少62%和28%。我们还在现场可编程门阵列上验证了该微架构，其功耗和资源消耗均较低。硬件与ISA评估均表明，HiSEP-Q在被控量子比特数量方面具有高可扩展性和高效率。