#define APB_MISC_BASE 0x70000000
#define PIN_UART1_TX 0x70003114
#define PAD_UART1_TX 0x700008BC

void _start() {
  *(volatile unsigned int *)(PIN_UART1_TX) = (1 << 6) | (1 << 4);

  *(volatile unsigned int *)(PAD_UART1_TX) = 0x00000000;    // Reset to defaults
  *(volatile unsigned int *)(PAD_UART1_TX) |= (0x1F << 12); // Max Drive Up
  *(volatile unsigned int *)(PAD_UART1_TX) |= (0x1F << 20); // Max Drive Down

  *(volatile unsigned int *)(0x60006010) |= (1 << 6);
  *(volatile unsigned int *)(0x7000600C) = 0x83;
  *(volatile unsigned int *)(0x70006000) = 0x71; // DLL for 1200 Baud @ 12MHz
  *(volatile unsigned int *)(0x70006004) = 0x02; // DLM
  *(volatile unsigned int *)(0x7000600C) = 0x03;

  while (1) {
    while (!(*(volatile unsigned int *)(0x70006014) & 0x20))
      ;
    *(volatile unsigned int *)(0x70006000) = 0x55; // Alternating bits
    for (volatile int i = 0; i < 1000000; i++)
      ;
  }
}