ARM uses a Load/Store based architecture. Explain how an ARM CPU would update a value stored in memory (RAM). You may support your answer with a relevant code example(s).

In an ARM CPU, to update a value stored in memory (RAM), the CPU first needs to load the value from memory into a register, then modify the value in the register, and finally store the updated value from the register back into memory.

Here is an example code snippet that demonstrates how to update a value stored in memory using ARM assembly language:

; Assume the value to be updated is stored at memory location 0x1000
LDR r0, =0x1000  ; Load the memory address into register r0
LDR r1, [r0]     ; Load the value at memory address 0x1000 into register r1
ADD r1, r1, #1   ; Add 1 to the value stored in register r1
STR r1, [r0]     ; Store the updated value back into memory address 0x1000

In this code example, the first instruction loads the memory address 0x1000 into register r0. The second instruction loads the value stored at memory address 0x1000 into register r1. The third instruction adds 1 to the value stored in register r1. Finally, the fourth instruction stores the updated value back into memory address 0x1000.

This sequence of load, modify, and store operations is a common pattern used in Load/Store architectures like ARM to update values stored in memory.