Chisel (programming language)

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Short description: Open-source hardware description language (HDL)
Constructing Hardware in a Scala Embedded Language (Chisel)
Chisel(ProgrammingLanguage)Logo.svg
ParadigmsMulti-paradigm: concurrent, functional, imperative, object-oriented
FamilyScala
DeveloperUniversity of California, Berkeley
First appearedJune 2012; 12 years ago (2012-06)
Stable release
3.6.0 / April 14, 2023; 14 months ago (2023-04-14)
Typing disciplineInferred, static, strong, structural
ScopeLexical (static)
Implementation languageScala
PlatformJava virtual machine (JVM)
JavaScript (Scala.js)
LLVM (Scala Native) (experimental)
Websitewww.chisel-lang.org

The Constructing Hardware in a Scala Embedded Language (Chisel)[1] is an open-source hardware description language (HDL) used to describe digital electronics and circuits at the register-transfer level.[2][3] Chisel is based on Scala as an embedded domain-specific language (DSL). Chisel inherits the object-oriented and functional programming aspects of Scala for describing digital hardware. Using Scala as a basis allows describing circuit generators. High quality, free access documentation exists in several languages.[4]

Circuits described in Chisel can be converted to a description in Verilog for synthesis and simulation.

Code examples

A simple example describing an adder circuit and showing the organization of components in Module with input and output ports:

class Add extends Module {
  val io = IO(new Bundle {
    val a = Input(UInt(8.W))
    val b = Input(UInt(8.W))
    val y = Output(UInt(8.W))
  })

  io.y := io.a + io.b
}

A 32-bit register with a reset value of 0:

val reg = RegInit(0.U(32.W))

A multiplexer is part of the Chisel library:

val result = Mux(sel, a, b)

Use

Although Chisel is not yet a mainstream hardware description language, it has been explored by several companies and institutions. The most prominent use of Chisel is an implementation of the RISC-V instruction set, the open-source Rocket chip.[5] Chisel is mentioned by the Defense Advanced Research Projects Agency (DARPA) as a technology to improve the efficiency of electronic design, where smaller design teams do larger designs.[6] Google has used Chisel to develop a Tensor Processing Unit for edge computing.[7] Some developers prefer Chisel as it requires 5 times lesser code and is much faster to develop than Verilog.[8]

Circuits described in Chisel can be converted to a description in Verilog for synthesis and simulation using a program named FIRRTL.[9][better source needed]

See also

References

  1. Bachrach, J.; Vo, H.; Richards, B.; Lee, Y.; Waterman, A.; Avižienis, R.; Wawrzynek, J.; Asanović, K. (June 2012). "Chisel: constructing hardware in a Scala embedded language". San Francisco, California, USA: Association for Computing Machinery (ACM). pp. 1216–25. doi:10.1145/2228360.2228584. ISBN 978-1-4503-1199-1. https://dl.acm.org/doi/abs/10.1145/2228360.2228584. 
  2. "Chisel". California, U.S.: University of California, Berkeley. https://people.eecs.berkeley.edu/~jrb/Projects/chisel/chisel.htm. 
  3. Bachrach, Jonathan, ed. "Chisel: Accelerating Hardware Design". California, U.S.: RISC-V International. https://riscv.org/wp-content/uploads/2015/01/riscv-chisel-tutorial-bootcamp-jan2015.pdf. 
  4. Schoeberl, Martin (August 30, 2019) (in en, zh, ja, vi). Digital Design with Chisel (2nd ed.). Kindle Direct Publishing. ISBN 978-1689336031. http://www.imm.dtu.dk/~masca/chisel-book.html. 
  5. Asanović, Krste. "rocket-chip". RISC-V International. https://github.com/ucb-bar/rocket-chip. 
  6. Moore, Samuel K. (2018-07-16). "DARPA Plans a Major Remake of U.S. Electronics". IEEE Spectrum (Institute of Electrical and Electronics Engineers (IEEE)). https://spectrum.ieee.org/tech-talk/computing/hardware/darpas-planning-a-major-remake-of-us-electronics-pay-attention. 
  7. Derek Lockhart, Stephen Twigg, Ravi Narayanaswami, Jeremy Coriell, Uday Dasari, Richard Ho, Doug Hogberg, George Huang, Anand Kane, Chintan Kaur, Tao Liu, Adriana Maggiore, Kevin Townsend, Emre Tuncer (2018-11-16). Experiences Building Edge TPU with Chisel. Retrieved 2020-06-10.
  8. "XiangShan open-source 64-bit RISC-V processor to rival Arm Cortex-A76 - CNX Software" (in en-US). 2021-07-05. https://www.cnx-software.com/2021/07/05/xiangshan-open-source-64-bit-risc-v-processor-rival-arm-cortex-a76/. 
  9. "Chisel/FIRRTL Hardware Compiler Framework". https://www.chisel-lang.org/. 

External links