Add documentation for the binary loader

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5278 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 19 insertions, 3 deletions

diff --git a/nuttx/README.txt b/nuttx/README.txt
index 4c008e6f1..d567d88c8 100644
--- a/nuttx/README.txt
+++ b/nuttx/README.txt
@@ -154,9 +154,15 @@ Notes about Header Files
 
     Even though you should not use a foreign C-Library, you may still need
     to use other, external libraries with NuttX.  In particular, you may
-    need to use the math library, libm.a.  The math libary header file,
-    math.h, is a special case.  If you do nothing, the standard math.h
-    header file that is provided with your toolchain will be used.
+    need to use the math library, libm.a.  NuttX supports a generic, built-in
+    math library that can be enabled using CONFIG_LIBM=y.  However, you may
+    still want to use a higher performance external math library that has
+    been tuned for your CPU.  Sometimes such such tuned math libraries are
+    bundled with your toolchain.
+
+    The math libary header file, math.h, is a then special case.  If you do
+    nothing, the standard math.h header file that is provided with your
+    toolchain will be used.
 
     If you have a custom, architecture specific math.h header file, then
     that header file should be placed at arch/<cpu>/include/math.h.  There
@@ -171,6 +177,16 @@ Notes about Header Files
     than to include that archicture-specific math.h header file as the
     system math.h header file.
 
+  float.h
+
+    If you enable the generic, built-in math library, then that math library
+    will expect your toolchain to provide the standard float.h header file.
+    The float.h header file defines the properties of your floating point
+    implementation.  It would always be best to use your toolchain's float.h
+    header file but if none is avaiable, a default float.h header file will
+    provided if this option is selected.  However, there is no assurance that
+    the settings in this float.h are actually correct for your platform!
+
   stdarg.h
 
     In most cases, the correct version of stdarg.h is the version provided with your toolchain.  However, sometimes there are issues with with using your toolchains stdarg.h.  For example, it may attempt to draw in header files that do not exist in NuttX or perhaps the header files that is uses are not compatible with the NuttX header files.  In those cases, you can use an architecture-specific stdarg.h header file by defining CONFIG_ARCH_STDARG_H=y.