Plasma

The Propeller Low-level Assembly Aggregator

Plasma is a small (637 lines of source code) tool for compiling and concatenating propeller assembly language (PASM) and binary data. It extends PASM with some new features, most notably ARM-like constant pools.

Background

When I began to work on my Turbulence demo, I soon realized that I was going to have to write my own assembler. The one from Parallax was bulky and inflexibly locked to the spin environment for which it was designed, and had to be run through wine. The open source alternatives weren't stable enough at the time. Consequently, I hacked together some prolog code and a bison parser.

I've decided to publish the source code here, as free software, in the hope that somebody will find it useful and inspiring.

Documentation

Documentation is scarce, because this tool was developed for my own private use. The source code is quite readable, though, since it's short and written in a high level programming language.

Here is an example of plasma source code, illustrating some of the new features. For the ultimate example, please refer to the turbulence source code.

' Constant declaration. Must begin at start of line, just like labels.
ABC         = $1000

' Every label will refer to one cog address and one hub address (accessible with @).
' Consider the following code, for example:
            org         0
	    horg        $1000

start       mov         r1, #start      ' Place the value 0 in r1.
            'mov         r1, #@start     ' This would cause an error, since $1000 doesn't fit in 9 bits.
	    mov         r1, =@start     ' Allocate a register in the constant pool, then refer to it.
	    mov         r1, =ABC	' Plasma will re-use the same constant pool register here.
            jmp         #start

            byte        "hello"         ' We are no longer aligned on a long boundary.
mylabel                                 ' @mylabel = $1015, mylabel = undefined due to unalignment.
	    align       4               ' Insert padding bytes until the cog address is long aligned (3 bytes).

            pool                        ' Plasma will put a long here, with the value $1000.

r1          res         1

            vfit        496             ' Verbose fit. Like 'fit', but prints how many registers are used.
	    vhfit       $2000           ' Verbose hub fit. Counts bytes rather than registers.

Download

• plasma-1.0 (Source code, 7 kB)

Install

To build, you'll need SWI-prolog, flex, bison and gcc. Edit the makefile to point out the include directory where your SWI-Prolog.h is located. You will end up with two files; plasma (the executable) and native.so. You have to specify the location of native.so when you run plasma, using the -l flag.

Run

Plasma is invoked like this:

plasma -l native.so -o output.bin input.s