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diff --git a/docs/src/wiki-deprecated/introduction.md b/docs/src/wiki-deprecated/introduction.md new file mode 100644 index 00000000..43fc9887 --- /dev/null +++ b/docs/src/wiki-deprecated/introduction.md @@ -0,0 +1,64 @@ +--- +layout: docs +title: "Introduction" +section: "chisel3" +--- +This document is a tutorial introduction to _Chisel_ (Constructing +Hardware In a Scala Embedded Language). Chisel is a hardware +construction language embedded in the high-level programming language +Scala. At some point we will provide a proper reference manual, in +addition to more tutorial examples. In the meantime, this document +along with a lot of trial and error should set you on your way to +using Chisel. _Chisel is really only a set of special class +definitions, predefined objects, and usage conventions within Scala, +so when you write Chisel you are actually writing a Scala +program that constructs a hardware graph._ However, for the tutorial we don't presume that you +understand how to program in Scala. We will point out necessary Scala +features through the Chisel examples we give, and significant hardware +designs can be completed using only the material contained herein. +But as you gain experience and want to make your code simpler or more +reusable, you will find it important to leverage the underlying power +of the Scala language. We recommend you consult one of the excellent +Scala books to become more expert in Scala programming. + +>Through the tutorial, we format commentary on our design choices as in +this paragraph. You should be able to skip the commentary sections +and still fully understand how to use Chisel, but we hope you'll find +them interesting. + +>We were motivated to develop a new hardware language by years of +struggle with existing hardware description languages in our research +projects and hardware design courses. _Verilog_ and _VHDL_ were developed +as hardware _simulation_ languages, and only later did they become +a basis for hardware _synthesis_. Much of the semantics of these +languages are not appropriate for hardware synthesis and, in fact, +many constructs are simply not synthesizable. Other constructs are +non-intuitive in how they map to hardware implementations, or their +use can accidentally lead to highly inefficient hardware structures. +While it is possible to use a subset of these languages and still get +acceptable results, they nonetheless present a cluttered and confusing +specification model, particularly in an instructional setting. + +>However, our strongest motivation for developing a new hardware +language is our desire to change the way that electronic system design +takes place. We believe that it is important to not only teach +students how to design circuits, but also to teach them how to design +*circuit generators* ---programs that automatically generate +designs from a high-level set of design parameters and constraints. +Through circuit generators, we hope to leverage the hard work of +design experts and raise the level of design abstraction for everyone. +To express flexible and scalable circuit construction, circuit +generators must employ sophisticated programming techniques to make +decisions concerning how to best customize their output circuits +according to high-level parameter values and constraints. While +Verilog and VHDL include some primitive constructs for programmatic +circuit generation, they lack the powerful facilities present in +modern programming languages, such as object-oriented programming, +type inference, support for functional programming, and reflection. + +>Instead of building a new hardware design language from scratch, we +chose to embed hardware construction primitives within an existing +language. We picked Scala not only because it includes the +programming features we feel are important for building circuit +generators, but because it was specifically developed as a base for +domain-specific languages. |
