[firmware] Add support for __attribute__ ((constructor))

We modify the linker scripts to include the .ctors and .dtors sections
and add some code to actually call them before we jump to the main()
function.

2 files changed, 12 insertions, 1 deletions

diff --git a/src/target/firmware/lib/Makefile b/src/target/firmware/lib/Makefile
index 85427439..987857c9 100644
--- a/src/target/firmware/lib/Makefile
+++ b/src/target/firmware/lib/Makefile
@@ -1,7 +1,7 @@
 
 LIBRARIES+=mini
 mini_DIR=lib
-mini_SRCS=vsprintf.c string.c ctype.c printf.c console.c \
+mini_SRCS=vsprintf.c string.c ctype.c printf.c console.c ctors.c \
 		changebit.S clearbit.S div64.S lib1funcs.S memcpy.S memset.S setbit.S testchangebit.S testclearbit.S testsetbit.S
 
 
diff --git a/src/target/firmware/lib/ctors.c b/src/target/firmware/lib/ctors.c
new file mode 100644
index 00000000..6136a884
--- /dev/null
+++ b/src/target/firmware/lib/ctors.c
@@ -0,0 +1,11 @@
+
+/* iterate over list of constructor functions and call each element */
+void do_global_ctors(const char *ctors_start, const char *ctors_end)
+{
+	typedef void (*func_ptr)(void);
+	func_ptr *func;
+
+	for (func = (func_ptr *) ctors_start;
+	     *func && (func != (func_ptr *) ctors_end); func++)
+		(*func)();
+}