How to stop CodeVision from generating the interrupt vector

Question

CodeVision has a lot of nice features, among them the automatic generation of the interrupt vector.

However, now I'm working on a very small bootloader, and I can't afford any interrupts. CodeVision still happily generates the interrupt vector at the beginning of the Flash memory, and I couldn't find a way to turn it off.

It is crucial, as the interrupt vector would take up 25% of the space in the flash memory for the smallest bootloader. (128 words bootloader, and the interrupt vector needs 32 words for a 16k atmega)

I set "Use an external startup initialization file" and I use my own startup.asm. Even if I don't include anything about the interrupt vectors, they are still generated for the executable.

• Daniel Grillo: Can you put your startup code and configuration here?
• vsz: Even if I have my startup.asm completely empty, and (for the test) don't have any initialization for anything (ports, timers, interrupts, etc.) the interrupt vector is still generated by the compiler. Actually, a completely empty startup.asm and a main source file only containing void main(){} still does generate the interrupt vectors. In the project configuration I couldn't find anything relevant, and I hunted on Google for possible #pragma settings, without luck so far.
• Daniel Grillo: How is your Code Generation config? Have you put Program type as 'Application' or 'Boot Loader'?
• vsz: Boot loader, but it happens with both.
• JimmyB: Have you seen this FAQ? I think it's rather gcc-specific but may be worth a read, especially #18.

Answer 1

Generally to remove whole section like that you will need to use a custom linker script and you may need to modify or remove some of the behind-the-scenes startup code that compilers usually throw in. Although for a 128 word bootloader, you may be better served writing it in assembly.

• vsz: I know. This has been discussed in the comments. The question is, how exactly to do it as I couldn't find a way for it in the mentioned compiler. And if I write it all in Assembly I still have to compile it to machine code.

Answer 2

The CodeVision Advanced (costing 50 € more than the standard version) has an option for it in the Project|Configure|C Compiler|Advanced menu.