why the code in /arch/arm/cpu/armv7m/start.s is very little? Is it complete?

In the code of arm/cpu/armv7m/start.s in u-boot2016.01 is too few compared to others.

.globl  reset
.type reset, %function
reset:
    b   _main

.globl  c_runtime_cpu_setup
c_runtime_cpu_setup:
    mov pc, lr

Is it complete?