See Quick start guide for First-In-First-Out Buffer (FIFO).

These functions manages FIFOs thanks to simple a API. The FIFO can be 100% full thanks to a double-index range implementation. For example, a FIFO of 4 elements can be implemented: the FIFO can really hold up to 4 elements. This is particularly well suited for any kind of application needing a lot of small FIFO. The maximum fifo size is 128 items (uint8, uint16 or uint32). Note that the driver, thanks to its conception, does not use interrupt protection.

Data Structures
struct	fifo_desc
	FIFO descriptor used by FIFO driver. More...

Typedefs
typedef struct fifo_desc	fifo_desc_t

Enumerations
enum	{ FIFO_OK = 0, FIFO_ERROR_OVERFLOW, FIFO_ERROR_UNDERFLOW, FIFO_ERROR }
	Error codes used by FIFO driver. More...

Functions
static void	fifo_flush (fifo_desc_t *fifo_desc)
	Flushes a software FIFO. More...

static uint8_t	fifo_get_free_size (fifo_desc_t *fifo_desc)
	Returns the remaining free spaces of the FIFO (in number of elements). More...

static uint8_t	fifo_get_used_size (fifo_desc_t *fifo_desc)
	Returns the number of elements in the FIFO. More...

int	fifo_init (fifo_desc_t fifo_desc, void buffer, uint8_t size)
	Initializes a new software FIFO for a certain 'size'. More...

static bool	fifo_is_empty (fifo_desc_t *fifo_desc)
	Tests if a FIFO is empty. More...

static bool	fifo_is_full (fifo_desc_t *fifo_desc)
	Tests if a FIFO is full. More...

static uint16_t	fifo_peek_uint16 (fifo_desc_t *fifo_desc)
	Gets a 16-bits element from the FIFO but does not remove it from the FIFO. More...

static uint32_t	fifo_peek_uint32 (fifo_desc_t *fifo_desc)
	Gets a 32-bits element from the FIFO but does not remove it from the FIFO. More...

static uint8_t	fifo_peek_uint8 (fifo_desc_t *fifo_desc)
	Gets a 8-bits element from the FIFO but does not remove it from the FIFO. More...

static int	fifo_pull_uint16 (fifo_desc_t fifo_desc, uint16_t item)
	Gets a 16-bits element from the FIFO and checks for a possible underflow. More...

static uint16_t	fifo_pull_uint16_nocheck (fifo_desc_t *fifo_desc)
	Gets a 16-bits element from the FIFO. More...

static int	fifo_pull_uint32 (fifo_desc_t fifo_desc, uint32_t item)
	Gets a 32-bits element from the FIFO and checks for a possible underflow. More...

static uint32_t	fifo_pull_uint32_nocheck (fifo_desc_t *fifo_desc)
	Gets a 32-bits element from the FIFO. More...

static int	fifo_pull_uint8 (fifo_desc_t fifo_desc, uint8_t item)
	Gets a 8-bits element from the FIFO and checks for a possible underflow. More...

static uint8_t	fifo_pull_uint8_nocheck (fifo_desc_t *fifo_desc)
	Gets a 8-bits element from the FIFO. More...

static int	fifo_push_uint16 (fifo_desc_t *fifo_desc, uint32_t item)
	Puts a new 16-bits element into the FIFO and checks for a possible overflow. More...

static void	fifo_push_uint16_nocheck (fifo_desc_t *fifo_desc, uint32_t item)
	Puts a new 16-bits element into the FIFO. More...

static int	fifo_push_uint32 (fifo_desc_t *fifo_desc, uint32_t item)
	Puts a new 32-bits element into the FIFO and checks for a possible overflow. More...

static void	fifo_push_uint32_nocheck (fifo_desc_t *fifo_desc, uint32_t item)
	Puts a new 32-bits element into the FIFO. More...

static int	fifo_push_uint8 (fifo_desc_t *fifo_desc, uint32_t item)
	Puts a new 8-bits element into the FIFO and checks for a possible overflow. More...

static void	fifo_push_uint8_nocheck (fifo_desc_t *fifo_desc, uint32_t item)
	Puts a new 8-bits element into the FIFO. More...

typedef struct fifo_desc fifo_desc_t

anonymous enum

Error codes used by FIFO driver.

Enumerator
FIFO_OK	Normal operation.
FIFO_ERROR_OVERFLOW	Attempt to push something in a FIFO that is full.
FIFO_ERROR_UNDERFLOW	Attempt to pull something from a FIFO that is empty.
FIFO_ERROR	Error condition during FIFO initialization.

static void fifo_flush ( fifo_desc_t * fifo_desc )

inlinestatic

Flushes a software FIFO.

Parameters

fifo_desc The FIFO descriptor.

References fifo_desc::read_index, and fifo_desc::write_index.

Referenced by run_fifo_flush_test(), run_fifo_overflow_test(), run_fifo_push_pull_test(), run_fifo_size_test(), and run_fifo_underflow_test().

static uint8_t fifo_get_free_size ( fifo_desc_t * fifo_desc )

inlinestatic

Returns the remaining free spaces of the FIFO (in number of elements).

Parameters

fifo_desc The FIFO descriptor.

Returns: The number of free elements.

References fifo_get_used_size(), and fifo_desc::size.

Referenced by run_fifo_flush_test(), and run_fifo_size_test().

static uint8_t fifo_get_used_size ( fifo_desc_t * fifo_desc )

inlinestatic

Returns the number of elements in the FIFO.

Parameters

fifo_desc The FIFO descriptor.

Returns: The number of used elements.

References fifo_desc::mask, fifo_desc::read_index, and fifo_desc::write_index.

Referenced by fifo_get_free_size(), fifo_is_full(), run_fifo_flush_test(), and run_fifo_size_test().

int fifo_init	(	fifo_desc_t *	fifo_desc,
		void *	buffer,
		uint8_t	size
	)

Initializes a new software FIFO for a certain 'size'.

Precondition: Both fifo descriptor and buffer must be allocated by the caller before.

Parameters

fifo_desc	Pointer on the FIFO descriptor.
buffer	Pointer on the FIFO buffer.
size	Size of the buffer (unit is in number of 'elements'). It must be a 2-power and <= to 128.

Returns: Status

Return values

FIFO_OK	when no error occurred.
FIFO_ERROR	when the size is not a 2-power.

References Assert, fifo_desc::buffer, FIFO_OK, fifo_desc::mask, fifo_desc::read_index, fifo_desc::size, fifo_desc::u8ptr, and fifo_desc::write_index.

Referenced by main().

static bool fifo_is_empty ( fifo_desc_t * fifo_desc )

inlinestatic

Tests if a FIFO is empty.

Parameters

fifo_desc The FIFO descriptor.

Returns: Status

Return values

true	when the FIFO is empty.
false	when the FIFO is not empty.

References fifo_desc::read_index, and fifo_desc::write_index.

Referenced by fifo_pull_uint16(), fifo_pull_uint32(), fifo_pull_uint8(), run_fifo_flush_test(), and run_fifo_size_test().

static bool fifo_is_full ( fifo_desc_t * fifo_desc )

inlinestatic

Tests if a FIFO is full.

Parameters

fifo_desc The FIFO descriptor.

Returns: Status

Return values

true	when the FIFO is full.
false	when the FIFO is not full.

References fifo_get_used_size(), and fifo_desc::size.

Referenced by fifo_push_uint16(), fifo_push_uint32(), and fifo_push_uint8().

static uint16_t fifo_peek_uint16 ( fifo_desc_t * fifo_desc )

inlinestatic

Gets a 16-bits element from the FIFO but does not remove it from the FIFO.

Parameters

fifo_desc The FIFO descriptor.

Return values

item	extracted element.

References fifo_desc::buffer, fifo_desc::mask, fifo_desc::read_index, and fifo_desc::u16ptr.

static uint32_t fifo_peek_uint32 ( fifo_desc_t * fifo_desc )

inlinestatic

Gets a 32-bits element from the FIFO but does not remove it from the FIFO.

Parameters

fifo_desc The FIFO descriptor.

Return values

item	extracted element.

References fifo_desc::buffer, fifo_desc::mask, fifo_desc::read_index, and fifo_desc::u32ptr.

static uint8_t fifo_peek_uint8 ( fifo_desc_t * fifo_desc )

inlinestatic

Gets a 8-bits element from the FIFO but does not remove it from the FIFO.

Parameters

fifo_desc The FIFO descriptor.

Return values

item	extracted element.

References fifo_desc::buffer, fifo_desc::mask, fifo_desc::read_index, and fifo_desc::u8ptr.

static int fifo_pull_uint16	(	fifo_desc_t *	fifo_desc,
		uint16_t *	item
	)

inlinestatic

Gets a 16-bits element from the FIFO and checks for a possible underflow.

Parameters

fifo_desc	The FIFO descriptor.
item	extracted element.

Returns: Status

Return values

FIFO_OK	when no error occurred.
FIFO_ERROR_UNDERFLOW	when the FIFO was empty.

References barrier, fifo_desc::buffer, FIFO_ERROR_UNDERFLOW, fifo_is_empty(), FIFO_OK, fifo_desc::mask, fifo_desc::read_index, and fifo_desc::u16ptr.

Referenced by run_fifo_push_pull_test(), and run_fifo_underflow_test().

static uint16_t fifo_pull_uint16_nocheck ( fifo_desc_t * fifo_desc )

inlinestatic

Gets a 16-bits element from the FIFO.

Parameters

fifo_desc The FIFO descriptor.

Returns: extracted element.

References barrier, fifo_desc::buffer, fifo_desc::mask, fifo_desc::read_index, and fifo_desc::u16ptr.

static int fifo_pull_uint32	(	fifo_desc_t *	fifo_desc,
		uint32_t *	item
	)

inlinestatic

Gets a 32-bits element from the FIFO and checks for a possible underflow.

Parameters

fifo_desc	The FIFO descriptor.
item	extracted element.

Returns: Status

Return values

FIFO_OK	when no error occurred.
FIFO_ERROR_UNDERFLOW	when the FIFO was empty.

References barrier, fifo_desc::buffer, FIFO_ERROR_UNDERFLOW, fifo_is_empty(), FIFO_OK, fifo_desc::mask, fifo_desc::read_index, and fifo_desc::u32ptr.

Referenced by run_fifo_push_pull_test(), and run_fifo_underflow_test().

static uint32_t fifo_pull_uint32_nocheck ( fifo_desc_t * fifo_desc )

inlinestatic

Gets a 32-bits element from the FIFO.

Parameters

fifo_desc The FIFO descriptor.

Returns: extracted element.

References barrier, fifo_desc::buffer, fifo_desc::mask, fifo_desc::read_index, and fifo_desc::u32ptr.

static int fifo_pull_uint8	(	fifo_desc_t *	fifo_desc,
		uint8_t *	item
	)

inlinestatic

Gets a 8-bits element from the FIFO and checks for a possible underflow.

Parameters

fifo_desc	The FIFO descriptor.
item	extracted element.

Returns: Status

Return values

FIFO_OK	when no error occurred.
FIFO_ERROR_UNDERFLOW	when the FIFO was empty.

References barrier, fifo_desc::buffer, FIFO_ERROR_UNDERFLOW, fifo_is_empty(), FIFO_OK, fifo_desc::mask, fifo_desc::read_index, and fifo_desc::u8ptr.

Referenced by run_fifo_push_pull_test(), and run_fifo_underflow_test().

static uint8_t fifo_pull_uint8_nocheck ( fifo_desc_t * fifo_desc )

inlinestatic

Gets a 8-bits element from the FIFO.

Parameters

fifo_desc The FIFO descriptor.

Returns: extracted element.

References barrier, fifo_desc::buffer, fifo_desc::mask, fifo_desc::read_index, and fifo_desc::u8ptr.

static int fifo_push_uint16	(	fifo_desc_t *	fifo_desc,
		uint32_t	item
	)

inlinestatic

Puts a new 16-bits element into the FIFO and checks for a possible overflow.

Parameters

fifo_desc	The FIFO descriptor.
item	extracted element.

Returns: Status

Return values

FIFO_OK	when no error occurred.
FIFO_ERROR_UNDERFLOW	when the FIFO was empty.

References barrier, fifo_desc::buffer, FIFO_ERROR_OVERFLOW, fifo_is_full(), FIFO_OK, fifo_desc::mask, fifo_desc::u16ptr, and fifo_desc::write_index.

Referenced by run_fifo_overflow_test(), and run_fifo_push_pull_test().

static void fifo_push_uint16_nocheck	(	fifo_desc_t *	fifo_desc,
		uint32_t	item
	)

inlinestatic

Puts a new 16-bits element into the FIFO.

Parameters

fifo_desc	The FIFO descriptor.
item	extracted element.

References barrier, fifo_desc::buffer, fifo_desc::mask, fifo_desc::u16ptr, and fifo_desc::write_index.

static int fifo_push_uint32	(	fifo_desc_t *	fifo_desc,
		uint32_t	item
	)

inlinestatic

Puts a new 32-bits element into the FIFO and checks for a possible overflow.

Parameters

fifo_desc	The FIFO descriptor.
item	extracted element.

Returns: Status

Return values

FIFO_OK	when no error occurred.
FIFO_ERROR_UNDERFLOW	when the FIFO was empty.

References barrier, fifo_desc::buffer, FIFO_ERROR_OVERFLOW, fifo_is_full(), FIFO_OK, fifo_desc::mask, fifo_desc::u32ptr, and fifo_desc::write_index.

Referenced by run_fifo_overflow_test(), and run_fifo_push_pull_test().

static void fifo_push_uint32_nocheck	(	fifo_desc_t *	fifo_desc,
		uint32_t	item
	)

inlinestatic

Puts a new 32-bits element into the FIFO.

Parameters

fifo_desc	The FIFO descriptor.
item	extracted element.

References barrier, fifo_desc::buffer, fifo_desc::mask, fifo_desc::u32ptr, and fifo_desc::write_index.

static int fifo_push_uint8	(	fifo_desc_t *	fifo_desc,
		uint32_t	item
	)

inlinestatic

Puts a new 8-bits element into the FIFO and checks for a possible overflow.

Parameters

fifo_desc	The FIFO descriptor.
item	extracted element.

Returns: Status

Return values

FIFO_OK	when no error occurred.
FIFO_ERROR_UNDERFLOW	when the FIFO was empty.

References barrier, fifo_desc::buffer, FIFO_ERROR_OVERFLOW, fifo_is_full(), FIFO_OK, fifo_desc::mask, fifo_desc::u8ptr, and fifo_desc::write_index.

Referenced by run_fifo_flush_test(), run_fifo_overflow_test(), run_fifo_push_pull_test(), and run_fifo_size_test().

static void fifo_push_uint8_nocheck	(	fifo_desc_t *	fifo_desc,
		uint32_t	item
	)

inlinestatic

Puts a new 8-bits element into the FIFO.

Parameters

fifo_desc	The FIFO descriptor.
item	extracted element.

References barrier, fifo_desc::buffer, fifo_desc::mask, fifo_desc::u8ptr, and fifo_desc::write_index.

Microchip® Advanced Software Framework

Data Structures

Typedefs

Enumerations

Functions