IEM Software Technical Overview 1.3.4. The OS layer

1.3.4. The OS layer

The OS layer interfaces the IEM kernel to your OS. It is shown in Figure 1.5, together with its associated components.

Figure 1.5. The OS layer, and associated components

The OS layer is veneer code that presents a fixed OS layer API to the IEM kernel, and implements the API by making OS-specific calls. This API provides functionality to the IEM kernel that includes:

registering and unregistering the kernel hooks that the OS must call
accessing OS-provided services, such as:
- determining the number of CPUs in the system, and the one that is currently being used
- allocating, setting, and freeing memory
- using a timer
- enabling and disabling pre-emption in the OS
- enabling and disabling interrupts
- outputting debugging messages.
getting various information about a task, such as:
- whether a task has been pre-empted
- whether a task is a real-time task
- whether a task is the OS idle task
- what the task ID is for a task.

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