@ this code produces the same binary as listing 1

  .syntax unified
  .cpu cortex-m4
  .thumb
  .text
  .global main
main:
   MOVS.N  R0, #8
   LDR.N   R1, =0X40023830
   STR.N   R0, [R1, #0]

   MOVS.N  R0, #0X55
   LSLS.N  R0, R0, #24
   LDR.N   R1, =0X40020C00
   STR.N   R0, [R1, #0]

   MOVS.N  R0, #0
   LDR.N   R1, =0X40020C14
   STR.N   R0, [R1, #0]

   MOVS.N  R4, #0xf
   LSLS.N  R4, R4, #12

circle:
   MOVS.N  R3, #1
   LSLS.N  R3, R3, #12

loop:
   LDR.N   R2, =0X00145854
delay:
   SUBS.N  R2, #1
   BNE.N   delay
updateLed:
   EORS.N  R0, R3
   STR.N   R0, [R1, #0]
   BNE.N loop

   LSLS.N  R3, R3, #1
   ANDS.N  R3, R4
   BNE.N   loop
   B.N     circle