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8fe4f41ce6
Partitions services into a separate file for each service. Updates API tables to incorporate missing APIs. Change-Id: Ia08b52b4865967beda02851cfe4a7d5ca4e8f596 Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
55 lines
2.6 KiB
ReStructuredText
55 lines
2.6 KiB
ReStructuredText
.. _nanokernel_lifos:
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Nanokernel LIFOs
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################
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Definition
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**********
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The LIFO is defined in :file:`kernel/nanokernel/nano_lifo.c`. It
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consists of a linked list of memory blocks that uses the first word in
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each block as a next pointer. The data is stored in last-in-first-out
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order.
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Function
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********
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When a message is added to the LIFO, the data is stored at the head of
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the list. Messages taken off the LIFO object are taken from the head.
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The LIFO object requires the first 32-bit word to be empty in order to
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maintain the linked list.
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The LIFO object does not store information about the size of the
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messages.
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The LIFO object remembers one waiting context. When a second context
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starts waiting for data from the same LIFO object, the first context
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remains waiting and never reaches the runnable state.
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APIs
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****
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The following APIs for a nanokernel LIFO are provided by :file:`nanokernel.h.`
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+------------------------------------------------+------------------------------------+
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| Call | Description |
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+================================================+====================================+
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| :c:func:`nano_lifo_init()` | Initializes a LIFO. |
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+------------------------------------------------+------------------------------------+
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| | :c:func:`nano_task_lifo_put()` | Adds item to a LIFO. |
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| | :c:func:`nano_fiber_lifo_put()` | |
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| | :c:func:`nano_isr_lifo_put()` | |
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+------------------------------------------------+------------------------------------+
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| | :c:func:`nano_task_lifo_get()` | Removes item from a LIFO, or fails |
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| | :c:func:`nano_fiber_lifo_get()` | and continues if it is empty. |
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| | :c:func:`nano_isr_lifo_get()` | |
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+------------------------------------------------+------------------------------------+
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| | :c:func:`nano_task_lifo_get_wait()` | Removes item from a LIFO, or waits |
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| | :c:func:`nano_fiber_lifo_get_wait()` | for an item if it is empty. |
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+------------------------------------------------+------------------------------------+
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| | :c:func:`nano_task_lifo_get_wait_timeout()` | Removes item from a LIFO, or waits |
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| | :c:func:`nano_fiber_lifo_get_wait_timeout()` | for an item for a specified time |
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| | | period if it is empty. |
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+------------------------------------------------+------------------------------------+
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