Exception handlers can be installed to deal with various system-level exceptions, such as alignment errors, resets, timers and so forth. Exception handling is a configurable feature of eCos and is enabled by default.
The range of values for the exception_number parameter in the functions below is hardware-dependent, as are the individual exceptions. See hal/ARCH/arch/v1_2_1/include/hal_intr for the exception vector definitions specific to a given architecture.
The exception handler is a function of the following type:
typedef void cyg_exception_handler_t( cyg_addrword_t data, cyg_code_t exception_number, cyg_addrword_t info ); |
cyg_exception_handler_t is the type used for functions which are called as a result of an exception. It is used in the function cyg_exception_set_handler().
void cyg_exception_set_handler(cyg_code_t exception_number, cyg_exception_handler_t *new_handler, cyg_addrword_t new_data, cyg_exception_handler_t **old_handler, void **old_data);Replace current exception handler. This may apply to either the thread, or to a global exception handler, according to how exception handling was configured (global or per-thread). The exception may be ignored, or used to specify a particular handler.
void cyg_exception_call_handler(cyg_handle_t thread, cyg_code_t exception_number, cyg_addrword_t exception_info);Invoke exception handler for the given exception number. The exception handler will be invoked with exception_info as its third argument.