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doc: Edit nanokernel_tasks for consistency and ReST :dfn: syntax

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Corrected an "is is" and other minor punctuation + grammatical edits.

Change-Id: I26f51809215a8ac77a20bc9d424e6a806e29ee50
Signed-off-by: L.S. Cook <leonax.cook@intel.com>
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L.S. Cook 2016-03-16 10:50:33 -07:00 • committed by Gerrit Code Review
commit c6be6f271c
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doc/kernel/nanokernel/nanokernel_tasks.rst
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@ -6,19 +6,19 @@ Task Services
Concepts Concepts
******** ********
A task is a preemptible thread of execution that implements a portion of A :dfn:`task` is a preemptible thread of execution that implements a portion of
an application's processing. It is is normally used to perform processing that an application's processing. It is normally used to perform processing that is
is too lengthy or complex to be performed by a fiber or an ISR. too lengthy or too complex to be performed by a fiber or an ISR.
A nanokernel application can define only a single application task, known A nanokernel application can define a single application task, known as the
as the *background task*, which executes when there is no fiber or ISR *background task*, which can execute only when no fiber or ISR needs to
that needs to execute. The entry point function for the background task execute. The entry point function for the background task is :code:`main()`,
is :c:func:`main()`, and must be supplied by the application. and it must be supplied by the application.
.. note:: .. note::
The background task is very different from the tasks used by a microkernel The background task is very different from the tasks used by a microkernel
application; for more information see application; for more information see :ref:`microkernel_tasks`.
:ref:`Microkernel Task Services <microkernel_tasks>`.
Task Lifecycle Task Lifecycle
============== ==============
@ -26,21 +26,21 @@ Task Lifecycle
The kernel automatically starts the background task during system The kernel automatically starts the background task during system
initialization. initialization.
Once the background task is started it executes forever. If the task attempts Once the background task is started, it executes forever. If the task attempts
to terminate by returning from :c:func:`main()`, the kernel puts the task into to terminate by returning from :code:`main()`, the kernel puts the task into
a permanant idling state since the background task must always be available a permanent idling state since the background task must always be available
to execute. to execute.
Task Scheduling Task Scheduling
=============== ===============
The nanokernel's scheduler executes the background task only when there is no The nanokernel's scheduler executes the background task only when no fiber or
fiber or ISR that needs to execute, since fiber and ISR execution takes ISR needs to execute; fiber and ISR executions always take precedence.
precedence.
The kernel automatically takes care of saving the background task's CPU register The kernel automatically saves the background task's CPU register values when
values when it performs a context switch to a fiber or an ISR. It restores prompted for a context switch to a fiber or ISR. These values are restored
these values when the background task later resumes execution. when the background task later resumes execution.
Usage Usage
@ -62,8 +62,8 @@ The application must supply a function of the following form:
} }
This function is used as the background task's entry point function. If a This function is used as the background task's entry point function. If a
nanokernel application does not need to perform any task-level processing nanokernel application does not need to perform any task-level processing,
:c:func:`main()` can simply do an immediate return. :code:`main()` can simply do an immediate return.
The :option:`MAIN_STACK_SIZE` configuration option specifies the size, The :option:`MAIN_STACK_SIZE` configuration option specifies the size,
in bytes, of the memory region used for the background task's stack in bytes, of the memory region used for the background task's stack