sb - 2008-02-23

I am writing a custom bootloader due to problems with built in bootloader and the need for additional features, and I of course ran into the problem with the absolut interrupt vector table residing in the booloader block of the code, but being used by the application code.

I saw a simple example using the user flag F0 in the PSW to select which routine to call, since this flag is independant of symbol tables and thus at the same absolut location whether in the bootloader code or in the application code.

Of course a flag could be declared as an absolut positioned bit at address 0x20.0 for instance, but the use of the F0 bit in PSW seemed like a good idea.

I assume SDCC does not use this flag, but a confirmation on this is appreciated before introducing a hard-to-find bug in the application.