In general gPXE files are licensed under the GPL.  GPLed files are in
general either from Linux or have been explicitly put under GPL by the
authors.  The license for a file is usually documented at the top of
the file.  

A few files are inherited from FreeBSD netboot and therefore can be
used under BSD or GPL.  Documented in this file are some of the
non-GPL'ed files.  If the internal documentation for a file disagrees
with what is documented in this file, the internal documentation for
the file shall be override this file.

File					Copyright status

src/core/misc.c				BSD
src/drivers/net/3c509.c			BSD
src/drivers/net/3c509.h			BSD
src/drivers/net/3c595.c			BSD
src/drivers/net/3c595.h			BSD
src/drivers/net/3c90x.c			Open Source
src/drivers/net/epic100.c		None
src/drivers/net/epic100.h		None
src/drivers/net/ns8390.c		BSD
src/drivers/net/ns8390.h		BSD
src/arch/i386/include/bits/string.h	None