Intel IXP1200 manual Msgqhandle Parameters, Msgqinitqueue, Msgqinitregs, Msgqsend

IXP1200 Network Processor Family ATM OC-3/12/Ethernet IP Router Example Design

4.6.1MSGQ_HANDLE Parameters

The following parameters make up MSGQ_HANDLE and are common to all macros in msgq.uc:

Parameter	Description
	GPR storing the current index into the queue. An absolute register is used to share the
io_index	index between threads. However, if the threads don’t share access to the queue, a relative
	GPR can be used.
in_base_addr	GPR storing the base address of the queue in RAM_TYPE (scratchpad or SRAM). An
	absolute GPR is used when the queue is shared between threads.
in_const_one	The value one in a GPR, typically absolute, or the constant 1. The register is generally
	used to save cycles.
BASE_ADDR	Base address of the queue in RAM_TYPE -- loaded into in_base_addr by msgq_init().
	Synchronization type, as follows:
	#define MSGQ_ASYNC 0 - return immediately, with or without data
SYNC_TYPE	#define MSGQ_SYNC_POLL 1 - wait for data -- poll while waiting
	#define MSGQ_SYNC_SLEEP 2 - wait for data -- sleep while waiting, sender must know
	to wake up receiver
RAM_TYPE	RAM type. Typically scratchpad, can also be SRAM.
MSGQ_SIZE	Number of longwords in the message queue. Must be a power of 2. 16 is typically used for
	scratchpad queues because it saves instructions.

4.6.2msgq_init_queue()

Initializes the global queue in RAM_TYPE. Called by central initialization code before queues are accessed.

msgq_init_queue(MSGQ_HANDLE)

Parameter	Description
MSGQ_HANDLE	Parameters described in “MSGQ_HANDLE Parameters”.

4.6.3msgq_init_regs()

Initializes the registers used to access the queue. Called by both producer and consumer.

msgq_init_regs(MSGQ_HANDLE)

Parameter	Description
MSGQ_HANDLE	Parameters described in “MSGQ_HANDLE Parameters”.

4.6.4msgq_send()

Sends a message to the queue.

Application Note 43

Modified on: 3/20/02,