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
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
連結已複製
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
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
