I am checking some terrible C source code; I haven't got any idea about how to maintain it or cooperate with it. But I found a very fundamental problem. It does NOT have a startup.asm; it has a startup.c using the powerful C extension "#pragma". So, the C runtime environment is setup by "#pragma section", "#pragma intvect", "#pragma asm". I quite worry about such a startup.c; so I contacted the FAE of our local distributor. The FAE is an experienced good engineer, but he told me that, this is not their standard way to setup C runtime environment; they definitely provided the startup.s from Day 1.
What will be the side-effect, when the C runtime environment is setup by the C extension "#pragma"?
BUT how do you know that the setup was "successful"?!
If the setup is broken, it will leave the system in a broken state - likely to cause problems in later execution.
A classic example is the many C51 posts where the setup is "broken" in that it does not correctly configure the XDATA access...