Adding two numbers using ARM assembly

test.s

// Assembly generally has three sections in the source
// .text - This is where all of the code lives       (Flash)
// .data - This is where all variables with value go (RAM)
// .bss  - This is where uninitialized variables go  (RAM)
//
// Since this program is super simple I just used the .text section
.text

  .word 0x20000000 // (address 0x0000.0000) This initializes the stack pointer
  b start + 1      // (address 0x0000.0004) This instructs the CPU to branch to start at reset

start:
  mov r0, #1       // Move the number 1 into register r0
  mov r1, #2       // Move the number 2 into register r1
  add r2, r1, r0   // Add r0 and r1 and store the result in r2

stop: b stop       // Just loop forever