You are looking at the top level of the freecalypso-sw source code tree.
The subtrees of this source tree are as follows:

loadtools	The suite of tools which run on a development host machine
		(normally PC/Linux desktop or laptop) and communicate with
		Calypso targets.  Starting from the Calypso ROM bootloader,
		these tools allow you to peek and poke registers, read and
		program flash, and load and execute experimental code in IRAM
		or XRAM.

nuc-fw		Nucleus-based firmware.  This tree contains the early beginnings
		of my (Michael Spacefalcon's) attempt to recreate TI's GSM
		firmware suite running under Nucleus RTOS.  The current code is
		in the earliest embryonic stages of development, and does not
		do anything useful yet.  The RTOS code is FreeNucleus, based on
		the Nucleus PLUS sources liberated by comrade XVilka and ported
		to build with gcc and run on the Calypso by Spacefalcon the
		Outlaw.

target-utils	These are utilities which run on Calypso targets, but which are
		independent of Nucleus, of any other RTOS, and of any larger
		firmware suite, i.e., totally standalone.  The two current
		utilities are loadagent, which is common for all currently
		supported Calypso targets and is required in order to use
		fc-loadtool or fc-xram (see loadtools), and pirexplore - the
		latter is a hardware exploration utility specific to the
		Pirelli DP-L10 target.

toolchain	Scripts and patches for building the gcc+binutils toolchain
		targeting ARM7, the CPU core of the Calypso GSM/GPRS baseband
		processor.  You'll need to build and install this toolchain
		first before you can build nuc-fw or target-utils.