#include <stdint.h>

#include "ch573/gpio.h"
#include "ch573/uart.h"
#include "ch573/pwr.h"

#include "isr_vector.h"

#define GPIO_PORT_A ch573_gpio__gpio_port_a
#define GPIO_PORT CH573_GPIO__GPIO_PORT_T_INTF

#define UART1 ch573_uart__uart1
#define UART CH573_UART__UART_T_INTF

#define PWR1 ch573_pwr__pwr_mgmt
#define PWR CH573_PWR__PWR_MGMT_T_INTF

/*
 * Function which delays for a bit.
 */
void delay(void);

void main(void);

uint32_t collatz(uint32_t n)
{
  uint32_t c = 0;

  while (n > 1) {
    if (n % 2 == 0) {
      n /= 2;
    } else {
      n = n * 3 + 1;
    }
    c++;
  }

  return c;
}

void blink_n(int n)
{
  uint32_t bit = 1 << 8;
  while (n > 0) {
    GPIO_PORT.out.set(GPIO_PORT_A, OFF, 8);
    delay();
    GPIO_PORT.out.set(GPIO_PORT_A, ON, 8);
    delay();
    --n;
  }
}

void delay(void)
{
  for (volatile uint32_t i = 0; i < 10000; ++i) {
    asm volatile("");
  }
}

volatile uint32_t deadbeef = 0xdeadbeef;

// Memory-mapped address of the data values in flash.
extern uint32_t DATA_VALUES_IN_FLASH;

// Where the data is located in sram.
extern uint32_t DATA_SEGMENT_START;
extern uint32_t DATA_SEGMENT_STOP;

#define gpio_usart1_tx_pin 9
#define gpio_usart1_rx_pin 8

const char* hello_world = "Hello, World!\r\n";

#define BAUD_RATE 115200

/* Main routine. This is called on_reset once everything else has been set up.
 */
void main(void)
{
  GPIO_PORT.dir.set(GPIO_PORT_A, DIR_OUT, gpio_usart1_tx_pin);
  GPIO_PORT.pd_drv.set(GPIO_PORT_A, 0, gpio_usart1_tx_pin);

  UART.div.set(UART1, 1);
  UART.fcr.set(UART1, 0x07);
  UART.ier.txd_en.set(UART1, ON);
  UART.lcr.word_sz.set(UART1, WORD_SZ_8_BITS);

  uint32_t dl = (10 * 6400000 / 8 / BAUD_RATE + 5) / 10;
  UART.dl.set(UART1, dl);
  
  // PWR.slp_clk_off_0.uart1.set(PWR1, CLK_SOURCE_ENABLED);

  const char* ptr = hello_world;

  while (1) {
    if (*ptr == 0) {
      ptr = hello_world;
    }

    while (!UART.lsr.thr_empty.get(UART1));
    UART.thr.set(UART1, *(ptr++));
  }
}

IRQ(systick)
{
  collatz(5);
}

IRQ(exc)
{
}

IRQ(nmi)
{
}