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Forum: ARM programming with GCC/GNU tools Trying to get C++ projct running on AT91SAM9G20-EK on SDRAM


Trying to get C++ projct running on AT91SAM9G20-EK on SDRAM
von Robin Mueller (Guest)

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Hi there,

I've been trying for some days to get a C++ project running. 
Unfortunately, there appears to be a problem with the board startup 
script and the linker script which were provided and are propably 
generated. These files we initially not intended to incorporate C++ code 
so now we're trying to adapt them to do just that. We are also using 
freeRTOS. I attached the code of the two files

1
/* ----------------------------------------------------------------------------

2
 *         ATMEL Microcontroller Software Support

3
 * ----------------------------------------------------------------------------

4
 * Copyright (c) 2008, Atmel Corporation

5
6
 * ----------------------------------------------------------------------------

7
 */

8
9
/*------------------------------------------------------------------------------

10
 *      Linker script for running in external SDRAM on the AT91SAM9G20

11
 *----------------------------------------------------------------------------*/

12
 

13
_Min_Heap_Size = 0x400;      /* required amount of heap. Added manually  */

14
_Min_Stack_Size = 0x800;    /* required amount of stack. Added manually */

15
16
OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")

17
OUTPUT_ARCH(arm)

18
ENTRY(entry)

19
20
MEMORY

21
{

22
    sram0 (W!RX) : ORIGIN = 0x200000, LENGTH = 16K

23
    sram1 (W!RX) : ORIGIN = 0x300000, LENGTH = 16K

24
    sdram (W!RX) : ORIGIN = 0x20000000, LENGTH = 32M /* this board provided 64M, but we are just using  32M to model another device which only has 32M external SDRAM */

25
 }

26
27
SECTIONS

28
{

29
    .fixed :

30
  {

31
        . = ALIGN(4);      /* tells the linker that these section ought to be word aligned */

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        _sfixed = .;

33
    KEEP(*(.startup));

34
        *(.text*)        /* Code is placed in .text */

35
        *(.rodata*)        /* global variables marked as const. are placed in .rodata */

36
        *(.glue_7)        /* glue arm to thumb code */

37
        *(.glue_7t)        /* glue thumb to arm code */

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        *(.eh_frame)

39
        *(.data)

40
        *(.data*)        /* contains all initialized global and static variables */

41
        *(.CP15_*)  /* required for system control coprocessor? */

42
        KEEP (*(.init))

43
      KEEP (*(.fini))

44
        . = ALIGN(4);

45
    /* preinit data */

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    PROVIDE_HIDDEN (__preinit_array_start = .);

47
    KEEP(*(.preinit_array))

48
    PROVIDE_HIDDEN (__preinit_array_end = .);

49
    

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    . = ALIGN(4);

51
    /* init data, the constructors are placed in this sections */

52
    PROVIDE_HIDDEN (__init_array_start = .);

53
    KEEP(*(SORT(.init_array.)))

54
    KEEP(*(.init_array))

55
    PROVIDE_HIDDEN (__init_array_end = .);

56
    

57
    . = ALIGN(4);

58
    /* finit data, destructors are placed in this section */

59
    PROVIDE_HIDDEN (__fini_array_start = .);

60
    KEEP(*(SORT(.fini_array.)))

61
    KEEP(*(.fini_array))

62
    PROVIDE_HIDDEN (__fini_array_end = .);

63
  } >sdram

64
65
  .ARM.extab (NOLOAD) : {

66
    *(.ARM.extab* .gnu.linkonce.armextab.*)

67
  } >sdram 

68
    

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  __exidx_start = .;

70
    .ARM.exidx (NOLOAD) : {

71
    *(.ARM.exidx* .gnu.linkonce.armexidx.*)

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  } > sdram

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    __exidx_end = .;

74
    _efixed = .;

75
76
    .prerelocate : AT (_efixed) /* all relocation stuff is pretty much taken from atmel */

77
    {

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        . = ALIGN(4);

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        _sprerelocate = .;

80
        . = ALIGN(4);

81
        _eprerelocate = .;

82
    }

83
84
    .postrelocate : AT (_sprerelocate + SIZEOF(.prerelocate))

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    {

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        . = ALIGN(4);

87
        _spostrelocate = .;

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        KEEP(*(.vectors));

89
    *(.sramfunc)

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        *(.ramfunc)

91
        . = ALIGN(4);

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        _epostrelocate = .;

93
    } >sram0

94
    

95
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    /* this section holds uninitialized global and static data  */

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   . = ALIGN(4);

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  .bss :

99
    {

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      /* This is used by the startup in order to initialize the .bss secion */

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      _sbss = .;         /* define a global symbol at bss start */

102
      __bss_start__ = _sbss;

103
      *(.bss)

104
      *(.bss*)

105
      *(COMMON)

106
  

107
      . = ALIGN(4);

108
      _ebss = .;         /* define a global symbol at bss end */

109
      __bss_end__ = _ebss;

110
    } >sdram

111
112
    /* User_heap_stack section, used to check that there is enough RAM left */

113
    ._user_heap_stack :

114
    {

115
      . = ALIGN(4);

116
      PROVIDE ( end = . );

117
      PROVIDE ( _end = . );

118
      . = . + _Min_Heap_Size;

119
      . = . + _Min_Stack_Size;

120
      . = ALIGN(4);

121
    } >sdram

122
123
  /* top of stack */

124
    _sstack = 0x22000000 - 1024;

125
}



And the start up script:

1
/* ----------------------------------------------------------------------------

2
 *         ATMEL Microcontroller Software Support 

3
 * --------------------------------------------------------------------------

4
  * Copyright (c) 2008, Atmel Corporation

5
* ----------------------------------------------------------------------------

6
 */

7
8
//------------------------------------------------------------------------------

9
//         Headers

10
//------------------------------------------------------------------------------

11
12
#include "board.h"

13
14
//------------------------------------------------------------------------------

15
//         Definitions

16
//------------------------------------------------------------------------------

17
18
#define IRQ_STACK_SIZE   8*3*4

19
20
#define ARM_MODE_ABT     0x17

21
#define ARM_MODE_FIQ     0x11

22
#define ARM_MODE_IRQ     0x12

23
#define ARM_MODE_SVC     0x13

24
25
#define I_BIT            0x80

26
#define F_BIT            0x40

27
28
//------------------------------------------------------------------------------

29
//         Startup routine

30
//------------------------------------------------------------------------------

31
32
            .align      4

33
            .arm

34
        

35
/* Exception vectors

36
 *******************/

37
            .section    .vectors, "a", %progbits

38
39
resetVector:

40
        ldr     pc, =resetHandler       /* Reset */

41
undefVector:

42
        b       undefVector             /* Undefined instruction */

43
swiVector:

44
    ldr     pc, =vPortYieldProcessor /* Software interrupt */

45
46
prefetchAbortVector:

47
        b       prefetchAbortVector     /* Prefetch abort */

48
dataAbortVector:

49
        b       dataAbortVector         /* Data abort */

50
reservedVector:

51
        b       reservedVector          /* Reserved for future use */

52
irqVector:

53
        b       irqHandler              /* Interrupt */

54
fiqVector:

55
                                        /* Fast interrupt */

56
//------------------------------------------------------------------------------

57
/// Handles a fast interrupt request by branching to the address defined in the

58
/// AIC.

59
//------------------------------------------------------------------------------

60
fiqHandler:

61
        b       fiqHandler

62
  

63
//------------------------------------------------------------------------------

64
/// Handles incoming interrupt requests by branching to the corresponding

65
/// handler, as defined in the AIC. Supports interrupt nesting.

66
//------------------------------------------------------------------------------

67
irqHandler:

68
69
/* Save interrupt context on the stack to allow nesting */

70
        sub     lr, lr, #4

71
        stmfd   sp!, {lr}

72
        mrs     lr, SPSR

73
        stmfd   sp!, {r0, lr}

74
75
/* Write in the IVR to support Protect Mode */

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        ldr     lr, =AT91C_BASE_AIC

77
        ldr     r0, [lr, #AIC_IVR]

78
        str     lr, [lr, #AIC_IVR]

79
80
/* Branch to interrupt handler in Supervisor mode */

81
        msr     CPSR_c, #ARM_MODE_SVC

82
        stmfd   sp!, {r1-r3, r4, r12, lr}

83
        blx     r0

84
        

85
/* Restore scratch/used registers and LR from User Stack */

86
/* Disable Interrupt and switch back in IRQ mode */      

87
        ldmia   sp!, {r1-r3, r4, r12, lr}

88
        msr     CPSR_c, #ARM_MODE_IRQ | I_BIT

89
90
/* Acknowledge interrupt */

91
        ldr     lr, =AT91C_BASE_AIC

92
        str     lr, [lr, #AIC_EOICR]

93
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/* Restore interrupt context and branch back to calling code */

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        ldmia   sp!, {r0, lr}

96
        msr     SPSR_cxsf, lr

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        ldmia   sp!, {pc}^

98
99
//------------------------------------------------------------------------------

100
/// Initializes the chip and branches to the main() function.

101
//------------------------------------------------------------------------------

102
            .section    .text

103
            .global     entry

104
105
entry:

106
resetHandler:

107
108
/* Useless instruction for referencing the .vectors section */

109
        ldr     r0, =resetVector

110
111
/* Set pc to actual code location (i.e. not in remap zone) */

112
      ldr     pc, =1f

113
114
/* Initialize the prerelocate segment */

115
1:

116
        ldr     r0, =_efixed

117
        ldr     r1, =_sprerelocate

118
        ldr     r2, =_eprerelocate

119
1:

120
        cmp     r1, r2

121
        ldrcc   r3, [r0], #4

122
        strcc   r3, [r1], #4

123
        bcc     1b

124
125
/* Perform low-level initialization of the chip using LowLevelInit() */

126
        ldr     sp, =_sstack

127
        stmfd   sp!, {r0}

128
      ldr     r0, =LowLevelInit

129
        blx     r0

130
131
/* Initialize the postrelocate segment */

132
133
        ldmfd   sp!, {r0}

134
        ldr     r1, =_spostrelocate

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        ldr     r2, =_epostrelocate

136
1:

137
        cmp     r1, r2

138
        ldrcc   r3, [r0], #4

139
        strcc   r3, [r1], #4

140
        bcc     1b

141
142
/* Clear the zero segment */

143
      ldr     r0, =__bss_start__

144
        ldr     r1, =__bss_end__

145
        mov     r2, #0

146
1:

147
        cmp     r0, r1

148
        strcc   r2, [r0], #4

149
        bcc     1b

150
151
/* Setup stacks

152
 **************/

153
/* IRQ mode */

154
        msr     CPSR_c, #ARM_MODE_IRQ | I_BIT | F_BIT

155
        ldr     sp, =_sstack

156
        sub     r4, sp, #IRQ_STACK_SIZE

157
158
/* Supervisor mode (interrupts enabled) */

159
        msr     CPSR_c, #ARM_MODE_SVC | F_BIT

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        mov     sp, r4

161
162
/* Call static constructors */

163
      ldr r0,=__libc_init_array

164
    mov lr,pc /* set the return address */

165
    bx r0 /* the target code can be ARM or THUMB */

166
/* Branch to main()

167
 ******************/

168
        ldr     r0, =main

169
        blx     r0

170
171
/* Loop indefinitely when program is finished */

172
1:

173
        b       1b


Do you have any idea why are program is crashing randomly? Right now it 
always crashes and jumps to an adress it is not intended to be. I 
attached the dissassembly when  this happends while debugging.
My guess is that this relates to the two files shown above. Maybe 
something is missing so that C++ is working properly? The program 
crashes when the freeRTOS task scheduler has already started. I hope 
someone has a clue how  to get this working. Especially someone who 
managed to get C++ working on ARM processors. Thanks a lot in advance !

Kind Regards,
Robin

  


  




  

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    Re: Trying to get C++ projct running on AT91SAM9G20-EK on SDRAM
  


  

    

      von
      
        Robin M.
        (spacefish)
        
      
      


      
    


    

      
    

    

    

  
  


  

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The program does not crash anymore when I comment out code related to 
hardware drivers. The program does not crash when performing these 
functions but crashes at the adresses I have shown in the 2 pictures. 
This is really confusing.
I use the AT91SAM9G20-EK board and provided drivers. This is inside a 
function which is called by performOperation() which crashed

1
//ATMEL

2
AT91S_USART * rs232; // do not initialize this register handle, causes problems !

3
USART_Configure(rs232, AT91C_US_USMODE_NORMAL,9600,BOARD_MCK);

4
USART_SetReceiverEnabled(rs232, true);

5
USART_SetTransmitterEnabled(rs232,true);

6
result = USART_IsDataAvailable(rs232);

7
if(result==1) {

8
  info << "Data available !" << std::endl;

9
}


  


  



  

  
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