n65 | An assembler for the 6502 microprocessor written in Ruby | Video Game library
kandi X-RAY | n65 Summary
kandi X-RAY | n65 Summary
This is an assembler for the Nintendo Entertainment System's 2A03 microprocessor. The 2A03 is an 8-bit processor based on the MOS 6502. This is a pretty straightfoward assembler, which is currently set up to produce iNES formatted ROM binaries from 6502 assembly language files. Here is a recent blog post that goes through creating a program with this n65, showing the essential syntax and more. Best thing until I create some real documentation. Inside An NES cartridge there are basically some number of ROM chips which contain banks of either program code or character (graphics) data. A PROG ROM bank is generally 16KB, and a CHAR ROM bank is generally 8KB. At least one PROG ROM bank is required, and the NES can address 2 PROG ROM banks and 1 CHAR ROM bank without the use of a mapper. This assembler works on the idea of defining these banks, and allowing you to specify their contents. When you then assemble your output ROM this assembler translates the assmebly code in your your PROG banks into executable binary segments, and also lets you organize and address data in your CHAR banks. In the end it jams all these banks together one after another, PROG first, then CHAR, and slaps an iNES header on the front of it. It is good at knowing which addressing modes are and are not allowed for each instruction, and contains some examples of correct syntax. This assembler can now handle bankswitching if you set a valid mapper in the header, write more than 2 PROG banks, and then and write whatever bankswitching code is nessessary for the mapper you've chosen. This assembler supports symbolic labels which can be scoped. When writing assembly it can be easy to run out of effective names for labels when they are scoped globally. I have seen other assemblers using anonymous labels to get around this but I decided I didn't like that syntax very much. Instead I opted to allow opening a new scope where you can reuse symbol names. You can give scopes names or allow them to be anonymous. If you choose to name a symbol scope you can use a dot syntax to address any symbols that are outside your current scope. I should put some example code up here showing this. I hoped to make writing NES libraries more effective since you can basically namespace your symbols into your own file and not mess with anyone else's code. I also have also been able to use this to create C style structs in the memory layout, ie sprite.x. The assembler does two passes over your code, any symbols that are used which it hasn't seen the definition for yet return a "promise", that are stored for the second pass. A "promise" is a fancy name for a lambda/closure which promises to come up with a value later, while your code continues on. It then evaluates all these "promises" during the assembler's second pass, which fills in the missing addresses etc. I have used this to compile some code for the NES, and it ran correctly on FCEUX, got it to make some sounds, load tiles, sprites, and scrolling. There is an example file included (shown below) that is a modified port of the NES101 tutorial by Michael Martin.
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Top functions reviewed by kandi - BETA
- Run the command line
- Create command line options
- Write the binary representation of an image
- Resolve the scope for a given scope .
- Resolve scopes for a given scope
- Serialize the binary string
- Processes a single line into a single line .
- Find an operator by name
- Converts a symbol to a symbolized symbolized keys .
- Writes the given address to the given address .
n65 Key Features
n65 Examples and Code Snippets
Community Discussions
Trending Discussions on n65
QUESTION
I have the following document for which I need to do mapping for elasticsearch
...ANSWER
Answered 2021-May-18 at 07:35There is no need to specify any particular mapping for array values.
If you will not define any explicit mapping, then the rows
field will be dynamically added as of the text
data type
There is no data type that is defined for arrays in elasticsearch. You just need to make sure that the rows
field contains the same type of data
Adding a working example with index data, search query, and search result
Index Mapping:
QUESTION
I'm doing on a GUI to extract position X and Y from GCode by using Regex and print it on richTextBox.
...ANSWER
Answered 2020-Jul-17 at 03:10Quick fix is to concatenate the text:
QUESTION
Hello I have a text string like this below and I am trying to use regular expressions to extract the Total Sales quantity which can be found right after the new line after the Total Sales\n43 for example 43 would the total sales. I am using the following command but I want to drop the Total Sales and the \n and just keep the quantity. I am wondering how I might go about this or will I need to do additional processing. Thanks
...ANSWER
Answered 2020-Feb-17 at 22:17Use positive look behind:(?<=Total Sales\n)\d{2}
. This way it checks if the Total Sales\n
string is preceding the pattern \d{2}
. And only capture that.
QUESTION
Good morning, I am trying to visualize an emoji graphml file in gephi, however, when I import it in, it keeps showing the black dots like here:
I am not sure what is going on. Am I missing something? Please give me little direction if you could, I am using Windows 10. I have never used the gephi before, and did a google search related to the problem, found few blogs, but that also didn't work out. Here is content of graphml file which I wrote it in R:
...ANSWER
Answered 2020-Jan-09 at 17:16We can use the plugin called imagepreview. The trick is, you need to have nodes as emoji images, and those emojis must have their utfs encoding as their name. You would also need a JAVA 6 JDK because a plugin hasn't seen an update since 2015.
If you have the imagepreview plugin installed, you should see a Node Images section at the bottom of the right-side Preview Settings bar. Tick Render nodes as images and specify the folder where the photos are located in the field below. And then have your data containing utfs point to the photo names.
QUESTION
I have a data.table with multiple columns of a variable "Performance" in specific years and a column named "ExPerf". I want to create a new column called FLAG which would indicate rows flagged for manual review based on these two conditions:
- Any of the "Performance" columns has a negative value
- The "ExPerf" column is different from any of the columns by more than 50%.
A mock data.table similar to the one I have:
...ANSWER
Answered 2019-Jul-15 at 15:12You can use the following code to check for your two conditions:
QUESTION
I am trying to create a VBScript to find and replace a certain string located between two strings. Here is an example of a file that the script will be executed on:
...ANSWER
Answered 2018-Mar-17 at 06:55I used the following approach to get the desired result:
- read all the contents of the File
- grab all the substrings beginning with
Tapper
and ending withM845
using regular expressions - In each substring, replace all the instances of
E10
withE
- Write the modified substring back to the file
Take help from this code:
QUESTION
I am trying to pull a graphviz format string from my database and pass to a javascript function on my browser front end. I am using NodeJS and EJS as the view engine. The following code is on my index.ejs to take the array of graph formats, graph_format and send to the viz.js function:
...ANSWER
Answered 2017-Jul-04 at 11:58i think here is error:-
QUESTION
I have a .sif file like this
...ANSWER
Answered 2017-Mar-09 at 15:41Have you tried SIF.js? I found it on npm: https://www.npmjs.com/package/sif.js
It's not quite the same JSON format as Cytoscape, but you could use it and .map()
the entries just a bit so that they match. Or you could use the code in the repo to build your own parsing function that directly outputs the Cytoscape format.
You can also use the Cytoscape desktop software to convert SIF to JSON, but that can't be automated as part of a JS app.
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Install n65
On a UNIX-like operating system, using your system’s package manager is easiest. However, the packaged Ruby version may not be the newest one. There is also an installer for Windows. Managers help you to switch between multiple Ruby versions on your system. Installers can be used to install a specific or multiple Ruby versions. Please refer ruby-lang.org for more information.
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