A Smalltalk binding of GNU lightning. GNU lightning exposes a portable interface for generating machine language at run-time. GNU lightning is fast and tries to be as little intrusive as possible, so that the generated code can also be optimized easily. So far, it has been ported to the x86, SPARC and PowerPC architecture.

With gst-lightining you can create and execute your own machine code inside gst. It create a function that can be called from gst.

Installation

From Source

The git source is available at: http://github.com/MrGwen/gst-lightning

   git clone git://github.com/MrGwen/gst-lightning.git

Now you need to generate configuration files:

   autoreconf -vi

And proceed to the classic build:

   ./configure
   make
   [sudo] make install

Example

To understand how it work let's start by an example.
We are going to reproduce the incr example from the lightning documentation.

   Eval [
       PackageLoader fileInPackage: 'Lightning'.
       jitState := Lightning.CJitState new.
       (jitState
           leaf: 1;
           getargInt: Lightning.R0 from: jitState argInt;
           addI: Lightning.RET to: Lightning.R0 int: 1;
           ret;
           assemble;
           value: 5) printNl.
   ]

• PackageLoader fileInPackage: 'Lightning'.

First we need to load the package that contain the gst source for the binding.

• jitState := Lightning.CJitState new.

Here we create the object that is going to contain all the machine code.

• jitState leaf: 1

This line added the prolog to the function. It also tell that the function will have one argument

• jitState getargInt: Lightning.R0 from: jitState argInt

We fetch the argument and store it in the genreal purpose register R0.
The offset of the argument is given by the jitState argInt statement.

• jitState addI: Lightning.RET to: Lightning.R0 int: 1

This step add 1 to the register R0 and store it into the return value designate by Lightning.RET

• jitState ret

We ended the function and return to the caller.

• jitState assemble

This statement is very important. It flushes the generated code and set it executable.

• (jitState value: 5) printNl

We call and print the output value of the function

You can found more example inside the examples directory from the source package.