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bsp_user's avatar
bsp_user
Icon for Occasional Contributor rankOccasional Contributor
3 years ago
Solved

arria v ds-5 arm compiler inline assembly

Hi,

I try to read the cntfreq register in arria V evaluation board , ds-5 arm compiler 5.

I use the following line:

__asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (val)));

compilation failed with #18: expected a ")"

whar am I dong wrong?

thanks

  • Jeet14's avatar
    Jeet14
    3 years ago

    Hi,


    compiler v7 can have the single line syntax like below-


    __asm("[;]");

    __asm{[;]}


    for reading CNTFREQ, assign global variable with volatile.

    And try to run again,


    volatile unsigned int freq=0;


    void printReg()

    {

    __asm

    {

    mrc p15, 0, freq, c14, c0, 0

    }

    printf("freq=0x%X", freq);

    }


    let me know if you have any query on this.


    Regards

    Jeetesh



7 Replies

  • Jeet14's avatar
    Jeet14
    Icon for Frequent Contributor rankFrequent Contributor
    3 years ago

    Hi,


    Its seems error in the syntax used-

    remove the one closing ) from the syntax.


    Regards

    Tiwari


    • bsp_user's avatar
      bsp_user
      Icon for Occasional Contributor rankOccasional Contributor
      3 years ago

      I apologies, I wrote it here wrong.

      I encountered two issues:

      1. I tried to use "regular" syntax which I saw in other places as well and it didn't work.

      (1.png)

      I don't know what is wrong with this syntax.

      2. I tried another syntax (2.png). now the code compiles but I have two problems:

      - There is no volatile statement

      - When I execute this asm code via debugger it halts when it reaches the asm code and that's it (I don't see the print value and can't continue to next step or running the debugger)

      Thank you

  • Jeet14's avatar
    Jeet14
    Icon for Frequent Contributor rankFrequent Contributor
    3 years ago

    Hi,


    Can you try changing your first syntax by below-

    __asm__ volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (freq));


    Regards

    Tiwari


    • bsp_user's avatar
      bsp_user
      Icon for Occasional Contributor rankOccasional Contributor
      3 years ago

      this is not working as well (the syntax).

      is it valid to arm compiler v5?

  • Jeet14's avatar
    Jeet14
    Icon for Frequent Contributor rankFrequent Contributor
    3 years ago

    Hi,

    If you have any other question on the matter, please let me know.

    Regards

    Jeetesh


    • bsp_user's avatar
      bsp_user
      Icon for Occasional Contributor rankOccasional Contributor
      3 years ago

      I replied to your previous message above. Thank you for your help

  • Jeet14's avatar
    Jeet14
    Icon for Frequent Contributor rankFrequent Contributor
    3 years ago

    Hi,


    compiler v7 can have the single line syntax like below-


    __asm("[;]");

    __asm{[;]}


    for reading CNTFREQ, assign global variable with volatile.

    And try to run again,


    volatile unsigned int freq=0;


    void printReg()

    {

    __asm

    {

    mrc p15, 0, freq, c14, c0, 0

    }

    printf("freq=0x%X", freq);

    }


    let me know if you have any query on this.


    Regards

    Jeetesh