The RTL source tree is divided in many subdirectories, but is very structured and easy to
understand. It mainly consists of three parts:
     
     - A OS-dependent directory. This contains the files that are different for each operating
     system. When compiling the RTL, you should do it here. The following directories
     exist:
         
         - amiga for the Amiga.
         
 
         - atari for the Atari.
         
 
         - beos for BeOS. It has one subdirectory for each of the supported processors.
         
 
         - bsd Common files for the various BSD platforms.
         
 
         - darwin for the unix-compatibility layer on Mac OS.
         
 
         - embedded A template for embedded targets.
         
 
         - emx OS/2 using the EMX extender.
         
 
         - freebsd for the FreeBSD platform.
         
 
         - gba Game Boy Advanced.
         
 
         - go32v2 For dos, using the GO32v2 extender.
         
 
         - linux  for  linux platforms.  It  has  one  subdirectory  for  each  of  the  supported
         processors.
         
 
         - macos for the Mac OS platform.
         
 
         - morphos for the MorphOS platform.
         
 
         - nds for the Nintendo DS platform.
         
 
         - netbsd for NetBSD platforms. It has one subdirectory for each of the supported
         processors.
                                                                            
                                                                            
         
 
         - netware for the Novell netware platform.
         
 
         - netwlibc for the Novell netware platform using the C library.
         
 
         - openbsd for the OpenBSD platform.
         
 
         - os2 for os/2.
         
 
         - palmos for the PalmOS Dragonball processor based platform.
         
 
         - posix for posix interfaces (used for easier porting).
         
 
         - solaris for the Solaris platform. It has one subdirectory for each of the supported
         processors.
         
 
         - symbian for the symbian mobile phone OS.
         
 
         - qnx for the QNX Realtime platform.
         
 
         - unix for unix common interfaces (used for easier porting).
         
 
         - win32 for Windows 32-bit platforms.
         
 
         - win64 for Windows 64-bit platforms.
         
 
         - wince for the Windows CE embedded platform (arm CPU).
         
 
         - posix for posix interfaces (used for easier porting).
 
      
     - A processor dependent directory. This contains files that are system independent, but
     processor dependent. It contains mostly optimized routines for a specific processor. The
     following directories exist:
         
         - arm for the ARM series of processors.
         
 
         - i386 for the Intel 80x86 series of processors.
         
 
         - m68k for the Motorola 680x0 series of processors.
         
 
         - powerpc for the PowerPC processor.
         
 
         - powerpc64 for the PowerPC 64-bit processor.
         
 
         - sparc for the SUN SPARC processor.
         
 
         - x86_64 for Intel compatible 64-bit processors such as the AMD64.
 
                                                                            
                                                                            
      
     - An OS-independent and Processor independent directory: inc. This contains complete units,
     and include files containing interface parts of units as well as generic versions of processor
     specific routines.
     
 
     - The Object Pascal extensions (mainly Delphi compatibility units) are in the objpas
     directory. The sysutils and classes units are in separate subdirectories of the objpas
     directory.