Most synchronous exception VSR table entries will point to a default -exception VSR which is responsible for handling all exceptions in a -generic manner. The default VSR simply saves the CPU state, makes any -adjustments to the CPU state that is necessary, and calls -cyg_hal_exception_handler().
cyg_hal_exception_handler() needs to pass the -exception on to some handling code. There are two basic destinations: -enter GDB or pass the exception up to eCos. Exactly which -destination is taken depends on the configuration. When the GDB stubs are -included then the exception is passed to them, otherwise it is passed -to eCos.
If an eCos application has been loaded by RedBoot then the VSR table -entries will all point into RedBoot's exception VSR, and will -therefore enter GDB if an exception occurs. If the eCos application -wants to handle an exception itself, it needs to replace the the VSR -table entry with one pointing to its own VSR. It can do this with the -HAL_VSR_SET_TO_ECOS_HANDLER() macro.