What does the hash (#) value associated with the ARM LDR instruction mean?

Question

I\'m trying to debug a crash I am experiencing in my application. The stack trace is pointing to an LDR instruction with the following format (thanks disassembler):

Answer 1

In GNU gas, the hash # is only required for ARMv7 when not using .syntax unified

For example, you can write it without # for ARMv8 aarch64-linux-gnu-as:

LDR x0, [x0,4]

or if use .syntax unified in arm-linux-gnueabihf-as:

.syntax unified
LDR x0, [x0,4]

More details at: Is the hash required for immediate values in ARM assembly?