I am trying to understand the compiled code for our ARM embedded system, using armclang compiler. Specifically, our code has a 64-bit signed division, which is translated to a call to the aeabi_ldivmod builtin. I was able to find its source code here, and it seems like it calls another builtin: __divmoddi4. Trying to look for the source code of this one, I come up with nothing. The closest thing I found is divmodsi4.S, but this is for 32-bit values.