Outline

Acquire fixed-sized memory block (with timeout).

C format

ER tget_mpf ( ID mpfid, VP *p_blk, TMO tmout );

Assembly format

MOVW AX, #tmout_hi PUSH AX MOVW AX, #tmout_lo PUSH AX MOVW BC, #LOWW(_p_blk) MOV A, #mpfid CALL !!_tget_mpf ADDW SP, #0x0004

Parameter(s)

I/O	Parameter	Description
I	ID mpfid;	ID number of the fixed-sized memory pool from which a memory block is acquired.
O	VP *p_blk;	Start address of the acquired memory block.
I	TMO tmout;	Specified timeout (unit: ticks). TMO_FEVR: Waiting forever. TMO_POL: Polling. Value: Specified timeout.

Explanation

This service call acquires the memory block from the fixed-sized memory pool specified by parameter mpfid and stores the start address in the area specified by parameter p_blk.

If a memory block could not be acquired from the target fixed-sized memory pool (no available memory blocks exist) when this service call is issued, memory block acquisition processing is not performed but the invoking task is queued to the target fixed-sized memory pool wait queue in the order of memory block acquisition request (FIFO order).

As a result, the invoking task is unlinked from the ready queue and is moved from the RUNNING state to the WAITING state (waiting state for a fixed-sized memory block).

The waiting state for a fixed-sized memory block is cancelled in the following cases, and then moved to the READY state.

Waiting State for a Fixed-sized Memory Block Cancel Operation	Return Value
A memory block was returned to the target fixed-sized memory pool as a result of issuing rel_mpf.	E_OK
Forced release from waiting (accept rel_wai while waiting).	E_RLWAI
Forced release from waiting (accept irel_wai while waiting).	E_RLWAI
Polling failure or timeout.	E_TMOUT

Note When TMO_FEVR is specified for wait time tmout, processing equivalent to get_mpf will be executed. When TMO_POL is specified, processing equivalent to pget_mpf will be executed.

Return value

Macro	Value	Description
E_OK	0	Normal completion.
E_RLWAI	-49	Forced release from waiting (accept rel_wai/irel_wai while waiting).
E_TMOUT	-50	Polling failure or timeout.