hello,

Subject: optimalization

Problem:
OS works fine with -O1 -O2 -O3 and -Os but fails after 7-100 (during return from vApplicationIdleHook, when IDLE task is active, undefined instruction interrupt is generated) ticks with -O2 flag (without optimalization), when I set configUSE_IDLE_HOOK to 0 OS does not crash! why???

Hardware: AT91SAM7S256
Compiler: GCC 4.1.1 (WinARM 2006.06.06)
OS: FreeRTOS 4.1.0 (independent), configTOTAL_HEAP_SIZE = 24000


best rgs
Janusz

void vApplicationIdleHook( void )
{
AT91C_BASE_PIOA->PIO_SODR = LED1;
}

code with -O1:

00109024 <vApplicationIdleHook>:
109024:2201 movsr2, #1
109026:4b01 ldrr3, [pc, #4](10902c <.text+0x102c>)
109028:631a strr2, [r3, #48]
10902a:4770 bxlr


0010a850 <prvIdleTask>:
10a850:b5f0 push{r4, r5, r6, r7, lr}
10a852:4e18 ldrr6, [pc, #96](10a8b4 <.text+0x28b4>)
10a854:4f18 ldrr7, [pc, #96](10a8b8 <.text+0x28b8>)
10a856:6833 ldrr3, [r6, #0]
10a858:2b00 cmpr3, #0
10a85a:d023 beq.n10a8a4 <prvIdleTask+0x54>
10a85c:f7ff f9e8 bl109c30 <vTaskSuspendAll>
10a860:683c ldrr4, [r7, #0]
10a862:f7ff ff29 bl10a6b8 <xTaskResumeAll>
10a866:2c00 cmpr4, #0
10a868:d01c beq.n10a8a4 <prvIdleTask+0x54>
10a86a:f005 f989 bl10fb80 <__vPortEnterCritical_from_thumb>
10a86e:683b ldrr3, [r7, #0]
10a870:2b00 cmpr3, #0
10a872:d101 bne.n10a878 <prvIdleTask+0x28>
10a874:2400 movsr4, #0
10a876:e003 b.n10a880 <prvIdleTask+0x30>
10a878:4b0f ldrr3, [pc, #60](10a8b8 <.text+0x28b8>)
10a87a:3308 addsr3, #8
10a87c:685b ldrr3, [r3, #4]
10a87e:68dc ldrr4, [r3, #12]
10a880:1d20 addsr0, r4, #4
10a882:f7ff f921 bl109ac8 <vListRemove>
10a886:4a0d ldrr2, [pc, #52](10a8bc <.text+0x28bc>)
10a888:6813 ldrr3, [r2, #0]
10a88a:3b01 subsr3, #1
10a88c:6013 strr3, [r2, #0]
10a88e:6833 ldrr3, [r6, #0]
10a890:3b01 subsr3, #1
10a892:6033 strr3, [r6, #0]
10a894:f005 f978 bl10fb88 <__vPortExitCritical_from_thumb>
10a898:6b20 ldrr0, [r4, #48]
10a89a:f7fe fe15 bl1094c8 <vPortFree>
10a89e:1c20 addsr0, r4, #0
10a8a0:f7fe fe12 bl1094c8 <vPortFree>
10a8a4:4b06 ldrr3, [pc, #24](10a8c0 <.text+0x28c0>)
10a8a6:681b ldrr3, [r3, #0]
10a8a8:2b01 cmpr3, #1
10a8aa:d900 bls.n10a8ae <prvIdleTask+0x5e>
10a8ac:df00 svc0
10a8ae:f7fe fbb9 bl109024 <vApplicationIdleHook>
10a8b2:e7d0 b.n10a856 <prvIdleTask+0x6>


code with -O0:

0010954c <vApplicationIdleHook>:
10954c:b580 push{r7, lr}
10954e:af02 addr7, sp, #8
109550:4a03 ldrr2, [pc, #12](109560 <.text+0x1560>)
109552:2301 movsr3, #1
109554:6313 strr3, [r2, #48]
109556:46bd movsp, r7
109558:b082 subsp, #8
10955a:bc80 pop{r7}
10955c:bc01 pop{r0}
10955e:4700 bxr0

0010c2a4 <prvIdleTask>:

/*
* -----------------------------------------------------------
* The Idle task.
* ----------------------------------------------------------
*
* The portTASK_FUNCTION() macro is used to allow port/compiler specific
* language extensions. The equivalent prototype for this function is:
*
* void prvIdleTask( void *pvParameters );
*
*/
static portTASK_FUNCTION( prvIdleTask, pvParameters )
{
10c2a4:b580 push{r7, lr}
10c2a6:b081 subsp, #4
10c2a8:af00 addr7, sp, #0
10c2aa:1c3b addsr3, r7, #0
10c2ac:6018 strr0, [r3, #0]
/* Stop warnings. */
( void ) pvParameters;

for( ;; )
{
/* See if any tasks have been deleted. */
prvCheckTasksWaitingTermination();
10c2ae:f000 f8b7 bl10c420 <prvCheckTasksWaitingTermination>

#if ( configUSE_PREEMPTION == 0 )
{
/* If we are not using preemption we keep forcing a task switch to
see if any other task has become available. If we are using
preemption we don't need to do this as any task becoming available
will automatically get the processor anyway. */
taskYIELD();
}
#endif

#if ( ( configUSE_PREEMPTION == 1 ) && ( configIDLE_SHOULD_YIELD == 1 ) )
{
/* When using preemption tasks of equal priority will be
timesliced. If a task that is sharing the idle priority is ready
to run then the idle task should yield before the end of the
timeslice.

A critical region is not required here as we are just reading from
the list, and an occasional incorrect value will not matter. If
the ready list at the idle priority contains more than one task
then a task other than the idle task is ready to execute. */
if( listCURRENT_LIST_LENGTH( &( pxReadyTasksLists[ tskIDLE_PRIORITY ] ) ) > ( unsigned portBASE_TYPE ) 1 )
10c2b2:4b04 ldrr3, [pc, #16](10c2c4 <.text+0x42c4>)
10c2b4:681b ldrr3, [r3, #0]
10c2b6:2b01 cmpr3, #1
10c2b8:d900 bls.n10c2bc <prvIdleTask+0x18>
{
taskYIELD();
10c2ba:df00 svc0
}
}
#endif

#if ( configUSE_IDLE_HOOK == 1 )
{
extern void vApplicationIdleHook( void );

/* Call the user defined function from within the idle task. This
allows the application designer to add background functionality
without the overhead of a separate task.
NOTE: vApplicationIdleHook() MUST NOT, UNDER ANY CIRCUMSTANCES,
CALL A FUNCTION THAT MIGHT BLOCK. */
vApplicationIdleHook();
10c2bc:f7fd f946 bl10954c <vApplicationIdleHook>
}
#endif
}
10c2c0:e7f5 b.n10c2ae <prvIdleTask+0xa>

for this code OS failed on:

Undef handler
OS tick count: 102
CurrentTCB: IDLE
parameters on TCB stack:
top of stack: 0x2014c4,
start of stack: 0x20106x
depth: 0x12c (x4)
critical nesting = 0
SPSR = 0x2000003f (main.c and tasks.c compiled in thumb mode)
R0 = 0x0010c2b3
R1 = 0x01010101
R2 = 0xfffff400
R3 = 0x00000001
R4 = 0x04040404
R5 = 0x05050505
R6 = 0x06060606
R7 = 0x0020150c
R8 = 0x08080808
R9 = 0x09090909
R10 = 0x10101010
R11 = 0x11111111
R12 = 0x12121212
R13 = 0x0020150c (SP)
R14 = 0x0010c2c1 (LR) <= it is wrong I think
R15 = 0x0010955c+instr (PC)

my second task:
xTaskCreate( vxTask, "vxTask", /*comSTACK_SIZE*/64+18+32, NULL, uxPriority + comRX_RELATIVE_PRIORITY, NULL );

static void vxTask( void *pvParameters )
{
(void) pvParameters;

while (1) {
AT91C_BASE_PIOA->PIO_CODR = LED4;
vTaskDelay(( portTickType ) 500/*ms*/);
AT91C_BASE_PIOA->PIO_SODR = LED4;
vTaskDelay(( portTickType ) 500/*ms*/);
//kprintf("abc\n");
}
}

when I comment vTaskDelay system does not crash with -O0 and idle hook turned on!!!

what is going on???!!!!!!!