inline assembly in ARM Cortex to load address of a C variable to register

[doubtsman]

Hi,

I am trying to load address of a C variable to register R3 using inline assembly using arm-none-eabi-gcc toolchain for cortex m4 microcontroller.

I am able to load the value of the variable but not sure how to load the address of variable. Any tips ?

volatile uint32_t val = 100;


asm("ldr    r3, %[value]"
    :
    : [value]"m"   (val) /* How to copy address of val to r3 ?*/
    : /* No clobbers */
   );

 

[danadakk]

How to access C variable for inline assembly manipulation?

Given this code: #include <stdio.h> int main(int argc, char **argv) { int x = 1; printf("Hello x = %d\n", x); } I'd like to access and manipulate the variable x in inline assembly.

stackoverflow.com

Using Inline Assembly in C/C++

This article describes using inline assembly code in your C/C++ program... was it ever difficult for you, it will never be any more!

www.codeproject.com

Regards, Dana.