nuttx

History

Gregory Nutt 2eff5a6c63 z20X: Continued development of the W25 Bootloader. Kconfig files. Repartition some functionality. Bootloader support will need to be provided in logic under arch/z80/src/ez80 so the critical configuration selections were moved the Kconfig file there. arch/z80/src/ez80/ez80_i2c.h: Rename arch/z80/src/ez80/ez80f91_i2c.h. It is sharable by both ez80f91 and ez80f92. arch/z80/src/ez80/: Add logic to perform an additional level of interrupt redirection. This is necessary because the the interrupt handling is part of the loader FLASH-based logic. In order to share interrupts with the program loaded into RAM by the loader, another layer or redirection is required to get control to the interrupt handlers in the loaded program. See ez809f2_loader.asm and ez80f92_program.asm boards/z80/ez80/z20x/scripts: Reduce size of the interrupt re-direction buffer from 1Kb to 512b.		2020-03-03 19:39:57 -03:00
..
libc	z20X: Continued development of the W25 Bootloader.	2020-03-03 19:39:57 -03:00
libdsp	Run codespell -w against all files	2020-02-22 14:45:07 -06:00
libnx	Build system: Get rid of the MOVEOBJ definition	2020-02-24 22:37:28 +01:00
libxx	arch: Customize the typedef of size_t instead of intptr_t	2020-02-18 07:15:19 -06:00
README.txt	libs/README.txt: Fix a typo	2020-01-27 08:46:46 +01:00

README.txt

README
======

This directory holds NuttX libraries.  Libraries in NuttX are very special
creatures.  They have these properties:

1. They can be shared by both application logic and logic within the OS when
   using the FLAT build.

2. But in PROTECTED and KERNEL modes, they must be built differently:  The
   copies used by applications and the OS cannot be the same.  Rather,
   separate versions of libraries must be built for the kernel and for
   applications.

3. When used by the OS, some special care must be taken to assure that the
   OS logic does not disrupt the user's errno value and that the OS does
   not create inappropriate cancellation points.

   For example, sem_wait() is both a cancellation point and modifies the
   errno value.  So within the FLAT build and without kernel version for
   the PROTECTED and KERNEL builds, the special internal OS interface
   nxsem_wait() must be used.  Within libraries, the macro _SEM_WAIT()
   (as defined in include/nuttx/semaphore.h) is used instead.  The
   definition of this macro accounts for the different usage environments.

NOTE:  The libraries under libs/ build differently from other NuttX
components:  There are no build-related files in the libs/ directory; it
is simply a container for other well-known, individual library directories.
The upper level Makefile logic is aware of the libraries within the libs/
container.

The only real function of the libs/ directory is to prevent the top-level
directory from becoming cluttered with individual libraries.