nodemips

nodemips is a MIPS assembling, emulation, and (essentially) manipulation
library. You can use it within other projects for your MIPS needs, or
simply run it to run a basic MIPS program.

How to Use

Library API documentation is yet to come. To run the simple test pogram
(test.asm), which is a demonstration that comes with nodemips,
simply run test.js (or nodemips-demo if globally installed via npm).

Usually, nodemips has a browser version, inside the browser folder.
If you want to rebuild that version, please note that, in order to
run Browserify (npm run build), there must be no browser field
in the package.json file of the jimp dependency. Apparently, Browserify
uses jimp's own browser version, the latter which requires many files
that don't exist.

This currently must be done manually, but only once per nodemips update.

Key Aspects

$3

Performance is decent for simpler programs, but there is most likely much
room for optimization. For comparison, the super-minimalistic test program
(test.asm), when run by test.js, takes around a second to run with debug
logs, but a small fraction of a second without debug logs.

$3

_Note: nodemips is still in an alpha stage, which means it doesn't have as
many features as it aims to eventually have._

*Don't expect an existing MIPS program, e.g. Super Mario 64, to run in
nodemips.** While architecture accuracy was a concern, this emulator simply
executes MIPS I instructions in a generic machine. It won't emulate
console-specific details, like graphics registers and interrupts for the
Nintendo 64.

Also, MIPS programs will most likely come in an executable
format, like ELF; nodemips follows a specific procedure in order to
execute a program. The easiest way to create a nodemips program is by
using the assembler (don't try to execute individual lines using
the assembler, it _won't work_). One may also set the Program Counter
(PC) to the address of the first instruction (usually, this address
will be in the text buffer space, i.e. between 0x00400000 and
0x0FFFFFFF), and set the initial values in the RAM, VRAM, error
handling instructions ROM, and maybe even the stack buffer, before
starting the machine, by either calling clock many times (although
this method won't allow blocking processes like reading on stdin),
or using the start, toggle (pause/unpause) and stop methods
(which might give lesser control over the flow of the CPU 'cycles').

* It has a 320x200 VGA mode 13h
memory and palette buffers, which may be used in order to display
graphics, granted that you can see the JIMP image returned by
the MIPSMachine.getVGA async method. To set the R, G and B of the
color #i in the VGA palette, simply syscall with $v0 = 0x3C (which
is 60, since, unlike i386 implementations of VGA, syscall slot 0x10
is taken), then set $a0, $a1, $a2, $a3 to, respectively, the
index i, and the red, green and blue channel values.

* Only a handful syscalls - printing, and (untested) stdin reading -, are
supported at the moment.

* The filesystem is not currently implemented. While it may eventually be
implemented in the Node.JS version, the browserify version will never
support a filesystem, due to the basic limitations of localStorage (or
any other persistent or permanent data storage mechanism) in browser
JavaScript engines.

* Sound is not yet supported.