get_mpl

Outline

Acquire variable-sized memory block (waiting forever).

C format

 ER      get_mpl (ID mplid, UINT blksz, VP *p_blk);

Parameter(s)

I/O	Parameter	Description
I	ID mplid;	ID number of the variable-sized memory pool from which a memory block is acquired.
I	UINT blksz;	Memory block size to be acquired (in bytes).
O	VP *p_blk;	Start address of the acquired memory block.

Explanation

This service call acquires a variable-size memory block of the size specified by parameter blksz from the variable-size memory pool specified by parameter mplid, and stores its start address into the area specified by parameter p_blk.

If no variable-size memory blocks could be acquired from the target variable-size memory pool (no successive areas equivalent to the requested size were available) when this service call is issued, this service call does not acquire variable-size memory blocks but queues the invoking task to the target variable-size memory pool wait queue and moves it from the RUNNING state to the WAITING state (variable-size memory block acquisition wait state).

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

WAITING State for a Variable-sized Memory Block Cancel Operation	Return Value
The variable-size memory block that satisfies the requested size was returned to the target variable-size memory pool as a result of issuing rel_mpl.	E_OK
The variable-size memory block that satisfies the requested size was returned to the target variable-size memory pool as a result of issuing irel_mpl.	E_OK
Forced release from waiting (accept rel_wai while waiting).	E_RLWAI
Forced release from waiting (accept irel_wai while waiting).	E_RLWAI

Note 1 The RI850V4 acquires variable-size memory blocks in the unit of "integral multiple of 4". If a value other than an integral multiple of 4 is specified for parameter blksz, it is rounded up to be an integral multiple of 4.

Note 2 Invoking tasks are queued to the target variable-size memory pool wait queue in the order defined during configuration (FIFO order or priority order).

Note 3 If the variable-size memory block acquisition wait state is cancelled because rel_wai or irel_wai was issued, the contents in the area specified by parameter p_blk become undefined.

Return value

Macro	Value	Description
E_OK	0	Normal completion.
E_PAR	-17	Parameter error. - blksz = 0x0 - blksz > 0x7fffffff
E_ID	-18	Invalid ID number. - mplid < 0x0 - mplid > Maximum ID number
E_CTX	-25	Context error. - This service call was issued from a non-task. - This service call was issued in the CPU locked state. - This service call was issued in the dispatching disabled state.
E_NOEXS	-42	Non-existent object. - Specified variable-sized memory pool is not registered.
E_RLWAI	-49	Forced release from the WAITING state. - Accept rel_wai/irel_wai while waiting.