Figure 4.16 – Renesas Emulator System M3T-MR100 User Manual

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T_MSG
header

Message
queue

Message A

Message B

Message C

Figure 4.16 Message queue

There are following data queue service calls that are provided by the MR100 kernel.

•

Send to Mailbox (snd_mbx, isnd_mbx)

Transmits a message. Namely, a message is dropped into the mailbox.

•

Receive from Mailbox (rcv_mbx, trcv_mbx)

Receives a message. Namely, a message is retrieved from the mailbox. At this time, if the mailbox has no mes-
sages in it, the task is kept waiting until a message is sent to the mailbox.

•

Receive from Mailbox (polling) (prcv_mbx, iprcv_mbx)

Receives a message. The difference from the rcv_mbx service call is that if the mailbox has no messages in it, the
task returns error code without going to a wait state.

•

Reference Mailbox Status (ref_mbx, iref_mbx)

Checks to see if there are any tasks waiting for a message to be put into the target mailbox and refers to the mes-
sage present at the top of the mailbox.