mips-parser

  

MIPS Assembly parser in JavaScript

MIPS is a reduced instruction set computer _(RISC)_ instruction set architecture developed by MIPS Technologies (formerly MIPS Computer Systems, Inc.).

MIPS is a _load-store_ architecture (also sometimes called _"register-register"_), meaning it only performs arithmetic and logic operations between CPU registers, requiring load/store instructions to access memory (as opposed to a _"register-memory"_ architecture, like x86).

The parser recognizes MIPS Assembly language, and produces segment-based AST, which can be used directly for interpretation, implementing a MIPS virtual machine, or emitting an actual bytecode corresponding to the instructions.

You can check the notes on the parser implementation, and also try it online.

$3

The parser can be installed as an NPM module:

``
npm install -g mips-parser

mips-parser --help
`

Or for developement, from the git repository. To regenerate the parser file after editing grammar file, run the build command:

`
git clone https://github.com/DmitrySoshnikov/mips-parser.git
cd mips-parser
npm install
npm run build

./bin/mips-parser --help
`

$3

MIPS parser can be used as a CLI tool, to parser a file:

`
mips-parser -f ~/example.s
`

Or direct expressions for quick syntax checks:

`
mips-parser -e 'li $v0, 4'
`

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The parser can also be used as a Node module:

`js
const MIPSParser = require('mips-parser');

const source =
li $v0, 4
la $a0, message
syscall
;

console.log(MIPSParser.parse(source)); // MIPS AST
`

$3

A basic MIPS program:

`asm


Hello, world!

li $v0, 10 # Terminate the program
syscall
`

We get the following AST, which can be interpreted by a virtual machine:

`json
{
"type": "Program",
"segments": {
".text": {
"instructions": [
{
"type": "Instruction",
"opcode": "li",
"operands": [
{
"type": "Register",
"value": "$v0",
"kind": "Name"
},
{
"type": "Number",
"kind": "decimal",
"value": 4
}
]
},
{
"type": "Instruction",
"opcode": "la",
"operands": [
{
"type": "Register",
"value": "$a0",
"kind": "Name"
},
{
"type": "Identifier",
"value": "out_string"
}
]
},
{
"type": "Instruction",
"opcode": "syscall"
},
{
"type": "Instruction",
"opcode": "li",
"operands": [
{
"type": "Register",
"value": "$v0",
"kind": "Name"
},
{
"type": "Number",
"kind": "decimal",
"value": 10
}
]
},
{
"type": "Instruction",
"opcode": "syscall"
}
]
},
".data": {
"instructions": [
{
"type": "Data",
"mode": ".asciiz",
"value": {
"type": "String",
"value": "Hello, world!"
}
}
]
}
},
"labels": {
"out_string": {
"address": 0,
"segment": ".data"
},
"main": {
"address": 0,
"segment": ".text"
}
},
"directives": [
{
"type": "Segment",
"value": ".data",
},
{
"type": "Segment",
"value": ".text",
}
]
}
`

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The mips-parser` is implemented using Syntax tool, which generates a LALR(1) parser based on the MIPS grammar.