Jeff,
The problem is the "C" functions are generated with parameters passed on
the stack while the "S" functions use registers er0-er3. The default
4.1.1 compiler is stack based so the half dozen "S" function calls fail.
Adding the "-mquickcall" makes my app work with the "S" functions and fail
with the "C" functions.
My current solution is to generate newlib with "CFLAGS=-mquickcall". Another
solution (perhaps better) would be to make the default compiler be
QUICKCALL. As we no not need leading underscores and a compiler tends to be
used for a long time, compiler mods are ok.