Embedded Systems Design, 2nd Edition

Real-time operating systems 233

• Generating a pseudo exception that is handled by separate

user exception handler(s)

This is even more formal — and slower — and effectively

replaces the processor level exception routine with a RTOS

level version in which the user creates his own vector table

and exception routines. Typically, all this is performed

through special kernel calls which register a task as the

handler for a particular exception. On completion, the

handler uses a special return from the exception call into the

RTOS kernel to signify that it has completed.

Memory model

The memory model that the processor offers can and often

varies with the model ...