diff --git a/sys/riscv/include/ieeefp.h b/sys/riscv/include/ieeefp.h
--- a/sys/riscv/include/ieeefp.h
+++ b/sys/riscv/include/ieeefp.h
@@ -5,4 +5,9 @@
 /* TODO */
 typedef int fp_except_t;
 
+__BEGIN_DECLS
+extern fp_except_t fpgetmask(void);
+extern fp_except_t fpsetmask(fp_except_t);
+__END_DECLS
+
 #endif /* _MACHINE_IEEEFP_H_ */