We use optional third-party analytics cookies to understand how you use GitHub. Learn more. You can always update your selection by clicking Cookie Preferences at the bottom of the page. For more information, see our Privacy Statement. We use essential cookies to perform essential website functions, e.
We use analytics cookies to understand how you use our websites so we can make them better, e. Skip to content. Instantly share code, notes, and snippets.
Code Revisions 1. Embed What would you like to do? Embed Embed this gist in your website. Share Copy sharable link for this gist.
Learn more about clone URLs. Download ZIP. Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment. You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window. Accept Reject. Essential cookies We use essential cookies to perform essential website functions, e. Analytics cookies We use analytics cookies to understand how you use our websites so we can make them better, e. Save preferences.
The D and A in the language specification. The inM input. If the current instruction needs. The outM and writeM outputs are combinational:. The addressM and pc outputs are clocked: although they.GitHub is home to over 50 million developers working together to host and review code, manage projects, and build software together. We use optional third-party analytics cookies to understand how you use GitHub.
Learn more. You can always update your selection by clicking Cookie Preferences at the bottom of the page. For more information, see our Privacy Statement. We use essential cookies to perform essential website functions, e.
We use analytics cookies to understand how you use our websites so we can make them better, e. Skip to content. Permalink Dismiss Join GitHub today GitHub is home to over 50 million developers working together to host and review code, manage projects, and build software together.
Sign up. Go to file T Go to line L Copy path. Raw Blame. You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window. Accept Reject. Essential cookies We use essential cookies to perform essential website functions, e.
For example. In order to figure out what this bit word means, if can be broken into the fields "i xx a cccccc ddd jjj". The i-bit codes the instruction type, which is 0 for an A-instruction, and 1 for a C-instruction. The two lines in question are splitting instruction into 2 pins. Maybe splitting them with a DMux might make more sense to you:. Learn more. Asked 5 years, 4 months ago.
Active 1 year, 8 months ago. Viewed 2k times. I have this CPU. Lundin k 22 22 gold badges silver badges bronze badges. Which language is this? Philippe, this is hdl from nand2tetris. Active Oldest Votes. Philippe Philippe 3, 18 18 silver badges 33 33 bronze badges. Come on. Please read your textbook before coming here to ask such basic questions.
From the book: In order to figure out what this bit word means, if can be broken into the fields "i xx a cccccc ddd jjj". Salar Salar 8 8 silver badges 13 13 bronze badges.This narrowing blocks blood flow to and from your heart and other organs. When blood flow to the heart is blocked, it can cause angina chest pain or a heart attack. A cholesterol test, or screening, tells your health care provider the levels of LDL and HDL cholesterol in your blood. This information helps your health care team determine your risk for heart disease or stroke.
Plaque is made up of cholesterol deposits. Plaque buildup causes the inside of the arteries to narrow over time. This process is called atherosclerosis. Skip directly to site content Skip directly to page options Skip directly to A-Z link. Section Navigation. Facebook Twitter LinkedIn Syndicate.
Minus Related Pages. Get Email Updates. To receive email updates about this page, enter your email address: Email Address. What's this? Links with this icon indicate that you are leaving the CDC website. Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
A hardware description language enables a precise, formal description of an electronic circuit that allows for the automated analysis and simulation of an electronic circuit. It also allows for the synthesis of an HDL description into a netlist a specification of physical electronic components and how they are connected togetherwhich can then be placed and routed to produce the set of masks used to create an integrated circuit.
A hardware description language looks much like a programming language such as C or ALGOL ; it is a textual description consisting of expressions, statements and control structures. One important difference between most programming languages and HDLs is that HDLs explicitly include the notion of time. HDLs form an integral part of electronic design automation EDA systems, especially for complex circuits, such as application-specific integrated circuitsmicroprocessorsand programmable logic devices.
Due to the exploding complexity of digital electronic circuits since the s see Moore's lawcircuit designers needed digital logic descriptions to be performed at a high level without being tied to a specific electronic technology, such as ECLTTL or CMOS. HDLs were created to implement register-transfer level abstraction, a model of the data flow and timing of a circuit.
There are different types of description in them: "dataflow, behavioral and structural". Example of dataflow of VHDL:. HDLs are standard text-based expressions of the structure of electronic systems and their behaviour over time.
Like concurrent programming languages, HDL syntax and semantics include explicit notations for expressing concurrency.
However, in contrast to most software programming languagesHDLs also include an explicit notion of time, which is a primary attribute of hardware. Languages whose only characteristic is to express circuit connectivity between a hierarchy of blocks are properly classified as netlist languages used in electric computer-aided design. HDL can be used to express designs in structural, behavioral or register-transfer-level architectures for the same circuit functionality; in the latter two cases the synthesizer decides the architecture and logic gate layout.
HDLs are used to write executable specifications for hardware. A program designed to implement the underlying semantics of the language statements and simulate the progress of time provides the hardware designer with the ability to model a piece of hardware before it is created physically. It is this executability that gives HDLs the illusion of being programming languageswhen they are more precisely classified as specification languages or modeling languages.
Simulators capable of supporting discrete-event digital and continuous-time analog modeling exist, and HDLs targeted for each are available.
LDL and HDL Cholesterol: "Bad" and "Good" Cholesterol
Generally, however, software programming languages do not include any capability for explicitly expressing time, and thus cannot function as hardware description languages. System Verilog is the first major HDL to offer object orientation and garbage collection.
Using the proper subset of hardware description language, a program called a synthesizer, or logic synthesis toolcan infer hardware logic operations from the language statements and produce an equivalent netlist of generic hardware primitives [ jargon ] to implement the specified behaviour.
Digital logic synthesizers, for example, generally use clock edges as the way to time the circuit, ignoring any timing constructs. The ability to have a synthesizable subset of the language does not itself make a hardware description language.The above is the fundamental reason for this series of posts. However, as a software engineer, you are limited in exposure to what that actually boils down to at the hardware level.
VHDL, really, is simple. You can get many other types of board even from Amazonand entry level ones are pretty affordable. As I write this now, the project is running code under simulation with basic arithmetic operations, addition, branching and memory access. I hope to learn much along the way whilst writing these articles. If you are an experienced hardware engineer and see me doing something a stupid, b inefficient, c unwise or d stupid, please do tell me by ways of twitter at domipheus.
This is not a superscalar processor. This will be a CPU that takes multiple instructions to execute the simplest of instructions. It comes with a very nice IDE, and associated toolchain — including a simulator. The next part will be about implementing the ram and register file, and testing it in the simulator. For now, here is a spoiler of the TPU in some simulator action, bonus points goes to the people who realise there is an odd thing about the form of the baz branch if Ra is zero instruction.
Thanks for reading, send all comments to domipheus on twitter! Ohh, and before I forget, this willl be completely open source. Part 2 in this series is now available. Ads have been removed from these pages. Instead, please consider these charities for donation: I am fundraising for Edinburgh children's hospital charity, where my daughter recieves treatment for leukaemia. Blood Cancer UK is a UK based charity dedicated to funding research into all blood cancers including leukaemia, lymphoma and myeloma.
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It only takes a minute to sign up. Preferably something well documented. I know I can look at opencoresbut I'm specifically interested in stuff people have actually looked at and found interesting.
Get this book, I've got the first edition. A lot depends on what is your purpose of studying the code? In other words, what does interesting mean to you?How a CPU is made
It will take a long time to dive in but you will get an appreciation for the overall big picture view of a complex microprocessor. However, if your purpose in studying a processor is to learn how to design one yourself, your best bet would be to start with one of the simple 8-bit machines there are many AVR,PIC examples on the net. You may try examining some Forth CPU designs.
Once there was Poderico's compiler from a C-like language to Picoblaze but it has been taken off the web. You may have a look at the Xilinx PicoBlaze processor. It's a minimal 8-bit embedded microcontroller, and the source code should be available. There is a course named fromNand2Tetris from University of Jerusalem, this course is also present on coursera, I built the computer they created in that course. I implemented the language in scheme to be able to see myself how the computer works in the least detail.
Subscribe to RSS
And I succeeded, the simulator they created in Java cannot do everything I wanted to see. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. Asked 10 years, 7 months ago. Active 2 years, 2 months ago.
Viewed 3k times. Sorry about the sucky tags, but as a new user I can't create new ones. It has some comments. OpenRISC has the advantage that it has a toolchain but is still relatively simple.