+/* set_stackptr without changing mode */
+void
+static __inline set_current_stackptr(u_int address)
+{
+	__asm __volatile("mov r13, %0" : /* no outputs */
+	    : "r" (address)
+	    : "r13" );
+}
+

It wouldn't surprise me if this seriously upsets the compiler.  Even 
making this non-inline may not work.

R.