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arria v ds-5 arm compiler inline assembly

bsp_user
Beginner
1,114 Views

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

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1 Solution
Jeet14
Employee
900 Views

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



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7 Replies
Jeet14
Employee
1,094 Views

Hi,


Its seems error in the syntax used-

remove the one closing ) from the syntax.


Regards

Tiwari


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bsp_user
Beginner
1,069 Views

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

 

 

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Jeet14
Employee
1,021 Views

Hi,


Can you try changing your first syntax by below-

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


Regards

Tiwari


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bsp_user
Beginner
933 Views

this is not working as well (the syntax).

is it valid to arm compiler v5?

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Jeet14
Employee
988 Views

Hi,

 

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

 

Regards

Jeetesh


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bsp_user
Beginner
933 Views

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

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Jeet14
Employee
901 Views

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



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