.syntax unified
.global main, EXTI0_IRQHandler, EXTI1_IRQHandler

.include "macros.s"

main:
  bl init_gpio
  bl init_audio
  bl starter

starter:
  mov r8, #0                    @ this will be our counter to ensure we only send 32 bits
  mov r6, #0                    @ we will use this for the received message
  mov r5, #32
  mov r0, #20
  bl delay                 @ this will be our counter to ensure we only receive 32 bits
  GPIOx_ODR_set E, 12
  bl delay
@  mov r10, #31                  @ counter to ensure we lsl correctly to get the msb every loop
  ldr r11, =0b10100001101110000111111111111111 @ store 440hz msg into r10
  bl sender
  bl clear_control_andCounter

sender:
  push {lr}
  cmp r8, #32
  it ne
  blne sender_message
  it eq
  bleq starter
  pop {lr}
  bl sender
  bx lr


sender_message:
  push {lr}
  mov r10, #0
  mov r10, r11  @r10 would be the binary msg
  lsr r10, #31
  cmp r10, #0
  it eq
  bleq write_bit_off
  it ne
  blne write_bit_on
  pop {lr}
  bx lr


write_bit_off:
  push {lr}
  mov r0, #10
  bl delay
  GPIOx_ODR_clear E, 14
  mov r0, #5
  bl delay
  GPIOx_ODR_toggle E, 13
  mov r0, #5
  bl delay
  add r8, #1
  lsl r11, #1
  pop {lr}
  bl sender

write_bit_on:
  push {lr}
  mov r0, #10
  bl delay
  GPIOx_ODR_set E, 14
  mov r0, #5
  bl delay
  GPIOx_ODR_toggle E, 13
  mov r0, #5
  bl delay
  @mov r0, #10
  @bl delay
  add r8, #1
  lsl r11, #1
  pop {lr}
  bl sender


clear_control_andCounter:
  push {lr}
  GPIOx_ODR_clear E, 12
  mov r8, #0
  pop {lr}
  bx lr



data_reader:
  push {lr}
  GPIOx_IDR_read E, 11
  it ne
  blne data_1_handler
  it eq
  bleq data_0_handler
  pop {lr}
  bx lr

data_0_handler:
  push {lr}
  sub r5, #1
  lsl r6, #1
  pop {lr}
  bx lr


data_1_handler:
  push {lr}
  mov r4, #0
  sub r5, #1
  mov r4, #1
  lsl r6, #1
  orr r6, r6, r4
  pop {lr}
  bx lr

@  ldr r0, =storage
@  ldr r1, [r0]
@  lsl r1, #1
@  str r1, [r0]

continue:
  push {lr}
  cmp r5, #0
  it ne
  blne data_reader
  pop {lr}
  bx lr


.type EXTI0_IRQHandler, %function
EXTI0_IRQHandler:
  push {lr}
  @ mark this interrupt as "cleared" (i.e. no longer pending)
  EXTI_PR_clear_pending 0
  GPIOx_IDR_read H, 0
  it eq
  moveq r7, #0
  it ne
  movne r7, #1
  pop {lr}
  bx lr


.type EXTI1_IRQHandler, %function
EXTI1_IRQHandler:
  push {lr}
  @ mark this interrupt as "cleared" (i.e. no longer pending)
  EXTI_PR_set_pending 0
  @ check if control is 0
  cmp r7, #1
  it eq  @ if not, continue to data_receiver
  bleq continue
  pop {lr}
  bx lr