Hardware design languages

Publications

• (PLDI 2024) Modular Hardware Design of Pipelined Circuits with Hazards.
  Minseong Jang, Jung In Rhee, Woojin Lee, Shuangshuang Zhao, Jeehoon Kang.
  ACM SIGPLAN conference on Programming Languages Design and Implementation.
  [paper: doi, local] ​ ​ ​
  

  Abstract

  Modular design is critical in reducing hardware designer's cognitive load and development cost. However, it is challenging to modularize high-performance pipelined circuits with structural, data, and control hazards because their resolution---stalling, and bypassing, and discard-and-restarting---introduce cross-stage dependencies. The dependencies could potentially mandate monolithic control logic and create combinational loops, hindering modular design. An effective method to modularize pipelined circuits is valid-ready interfaces, but they apply to a relatively simple form of pipelined circuits only with structural hazards.

  We propose hazard interfaces, a generalization of valid-ready interfaces that can modularize pipelined circuits not only with structural but also with data and control hazards. The key idea is enveloping the cross-stage dependencies within interfaces. We also design combinators for hazard interfaces in the style of map-reduce that facilitate decomposition of control logic. We implement a compiler (to synthesizable Verilog) for a prototype language supporting hazard interfaces and combinators, and design a sound and efficient type checker that proves the absence of combinational loops. With case studies on 5-stage RISC-V CPU core and 100Gbps Ethernet NIC, we demonstrate that hazard interfaces indeed facilitate modular design while incurring no noticeable cost in performance, power, and area over reference designs in Chisel and Verilog.

• (ASPLOS 2023) ShakeFlow: Functional Hardware Description with Latency-Insensitive Interface Combinators.
  Sungsoo Han†, Minseong Jang†, Jeehoon Kang (†: co-first authors in alphabetical order).
  The International Conference on Architectural Support for Programming Languages and Operating Systems.
  [paper: doi, local] ​ [artifact: development] ​ ​
  

  Abstract

  Functional programming’s benefits for hardware description have long been recognized in the literature. In particular, functional hardware description languages provide combinators such as maps and filters to facilitate the compositional description of circuits. However, it is challenging to apply functional programming with combinators to complex circuits with latency-insensitive interfaces such as valid/ready interfaces due to the cyclic nature of their forward and backward ports.

  In this work, we present ShakeFlow: the first functional hardware description language supporting latency-insensitive interface combinators. ShakeFlow provides extensible support for custom interfaces and combinators and a compiler to synthesizable Verilog and FIRRTL. We port a part of the BaseJump STL library and the Corundum 100Gbps NIC from (System)Verilog to ShakeFlow, reducing the code size by 38% and 26%, respectively. By experimenting with Corundum, we demonstrate that ShakeFlow is capable of designing realistic circuits, and porting to ShakeFlow does not incur significant resource and performance overhead.