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#include "board.h"
#include "uart.h"
 
#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
 
#define WAIT_FOR_XMITR \
        do { \
                lsr = REG8(UART_BASE + UART_LSR); \
        } while ((lsr & BOTH_EMPTY) != BOTH_EMPTY)
 
#define WAIT_FOR_THRE \
        do { \
                lsr = REG8(UART_BASE + UART_LSR); \
        } while ((lsr & UART_LSR_THRE) != UART_LSR_THRE)
 
#define CHECK_FOR_CHAR (REG8(UART_BASE + UART_LSR) & UART_LSR_DR)
 
#define WAIT_FOR_CHAR \
         do { \
                lsr = REG8(UART_BASE + UART_LSR); \
         } while ((lsr & UART_LSR_DR) != UART_LSR_DR)
 
void uart_init(void)
{
  int divisor;
 
  /* Reset receiver and transmiter */
  REG8(UART_BASE + UART_FCR) = UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT | UART_FCR_TRIGGER_14;
 
  /* Disable all interrupts */
  REG8(UART_BASE + UART_IER) = 0x00;
 
  /* Set 8 bit char, 1 stop bit, no parity */
  REG8(UART_BASE + UART_LCR) = UART_LCR_WLEN8 & ~(UART_LCR_STOP | UART_LCR_PARITY);
 
  /* Set baud rate */
  divisor = IN_CLK/(16 * UART_BAUD_RATE);
  REG8(UART_BASE + UART_LCR) |= UART_LCR_DLAB;
  REG8(UART_BASE + UART_DLL) = divisor & 0x000000ff;
  REG8(UART_BASE + UART_DLM) = (divisor >> 8) & 0x000000ff;
  REG8(UART_BASE + UART_LCR) &= ~(UART_LCR_DLAB);
}
 
void uart_putc(char c)
{
  unsigned char lsr;
 
  WAIT_FOR_THRE;
  REG8(UART_BASE + UART_TX) = c;
  if(c == '\n') {
    WAIT_FOR_THRE;
    REG8(UART_BASE + UART_TX) = '\r';
  }
  WAIT_FOR_XMITR;
}
 
char uart_getc(void)
{
  unsigned char lsr;
  char c;
 
  WAIT_FOR_CHAR;
  c = REG8(UART_BASE + UART_RX);
  return c;
}
 
char *str = "Hello world!!!\n";
int main (void)
{
  char *s;
 
  uart_init ();
  for (s = str; *s; s++)
    uart_putc (*s);
 
  while (1)
    uart_putc (uart_getc () + 1);
 
  return 0;
}