Overview

This directory contains programs written in NED1 assembly for use with the NEDsim screensaver.

Status

All programs in this directory are complete and verified to run on NEDsim.

Instructions

First, note that none of this is necessary if you simply wish to run a custom program on the NEDsim screensaver. Any NED1 a.out format executable may be passed to the screensaver on the CLI using the flag -binary filename.out.

The instructions that follow explain how to directly embed NED machine code in the NEDsim binary as built-in, default programs.

The first step is simply copying a NED1 assembly file into the present directory with a .ned_asm suffix. The filename (minus the suffix) determines the identifier name in C. For example, if you add a file named example.ned_asm, then in C it would be accessed as example[] and its size would be tracked in example_size.

The second step requires editing NEDsim.c in the parent directory, adding a new entry to the ned_programs[] array based on the name chosen in the previous step. Continuing the previous example, the new entry would resemble this:

{
    example,
    &example_size,
    0x20000000
}

Note that 0x20000000 is the address of the RAM Window displayed by the screensaver. You may move this window around if you wish to display a different region of system memory; it has no bearing on code execution, only on the screensaver’s display. Since code is loaded starting at 0x20000000, using this value will display the machine code and is a suitable fallback for programs without interesting memory patterns.

With your NED1 assembly file in this directory and an appropriate entry added to the NEDsim.c file, simply recompile NEDsim and your code will be embedded in the NEDsim binary as a new default program.