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RENESAS TOOL NEWS on November 16, 2004: RSO-M3T-MR32R_1-041116D
A Note on Using Real-Time OS M3T-MR32R
--On Entering a Task for the Call or
Acceptance of a Rendezvous or
the Acquisition of a Variable-Size
Memory Pool into a SUSPEND State--
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Please take note of the following problem in using the M3T-MR32R real-time OS:
- On entering a task for the call or acceptance of a rendezvous or
the acquisition of a variable-size memory pool into a SUSPEND state
- Versions Concerned
M3T-MR32R V.3.00 Release 1 through V.3.50 Release 2
- Description
When such a task as the call or acceptance of a rendezvous or the
acquisition of a variable-size memory pool is entered into a SUSPEND
state by an isus_tsk system call, the task will not go to
a WAIT-SUSPEND state.
- Conditions
This problem occurs if the following conditions are all satisfied:
| (1) | A task issues any of the following system calls; then goes to
a WAIT state:
acp_por, tacp_por, cal_por, tcal_por, get_blk, and tget_blk |
| (2) | An isus_tsk system call is issued inside the interrupt handler
invoked during the execution of the system call issued in (1). |
| (3) | The task that is the object of isus_tsk in (2) is the one that
issued a system call in (1). |
- Workaround
This problem can be circumvented either of the following ways:
| (1) | Before and after issuing the system call stated in Condition (1)
above, disable and enable an interrupt respectively.
Example:
-----------------------------------------------------
void task(INT stacd)
{
. . . . . . . . . . . . . . .
/* Disable an interrupt */
asm(" mvfc R0,PSW\n"
" and3 R0,R0,#0xFFBF\n"
" mvtc R0,PSW\n");
ercd = cal_por((VP)msg,&size,ID_por2,0x1,7);
/* Enable the interrupt */
asm(" mvfc R0,PSW\n"
" or3 R0,R0,#0x0040\n"
" mvtc R0,PSW\n");
. . . . . . . . . . . . . . .
}
-----------------------------------------------------
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| (2) |
Perform the following steps to enter a task into a SUSPEND state:
- Issue an ista_tsk system call to invoke the task to enter into SUSPEND state.
- Issue a sus_tsk system call from the invoked task mentioned above.
Example:
-----------------------------------------------------
void handler(void)
{
. . . . . . . . . . . . . . .
/* Comment out isus_tsk, issue ista_tsk to invoke ta
to enter into SUSPEND state, and pass ID of
objective task to ista_tsk as startup code */
/* isus_tsk( ID_task1 ); */
ista_tsk( ID_DoSuspend,(INT)ID_task1 );
. . . . . . . . . . . . . . .
}
void DoSuspend(INT tskid)
{
sus_tsk(tskid);
}
----------------------------------------------------- |
- Schedule of Fixing the Problem
We plan to fix this problem in our next release of the product.
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