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void outb(unsigned char value, unsigned short port)
{
__builtin_outb(value, port);
}
unsigned char inb(unsigned short port)
{
return __builtin_inb(port);
}
/* Base Address */
#ifndef TTYS0_BASE
#define TTYS0_BASE 0x3f8
#endif
#ifndef TTYS0_BAUD
#define TTYS0_BAUD 115200
#endif
#if ((115200%TTYS0_BAUD) != 0)
#error Bad ttys0 baud rate
#endif
#if TTYS0_BAUD == 115200
#define TTYS0_DIV (1)
#else
#define TTYS0_DIV (115200/TTYS0_BAUD)
#endif
/* Line Control Settings */
#ifndef TTYS0_LCS
/* Set 8bit, 1 stop bit, no parity */
#define TTYS0_LCS 0x3
#endif
#define UART_LCS TTYS0_LCS
/* Data */
#define UART_RBR 0x00
#define UART_TBR 0x00
/* Control */
#define UART_IER 0x01
#define UART_IIR 0x02
#define UART_FCR 0x02
#define UART_LCR 0x03
#define UART_MCR 0x04
#define UART_DLL 0x00
#define UART_DLM 0x01
/* Status */
#define UART_LSR 0x05
#define UART_MSR 0x06
#define UART_SCR 0x07
int uart_can_tx_byte(void)
{
return inb(TTYS0_BASE + UART_LSR) & 0x20;
}
void uart_wait_to_tx_byte(void)
{
while(!uart_can_tx_byte())
;
}
void uart_wait_until_sent(void)
{
while(!(inb(TTYS0_BASE + UART_LSR) & 0x40))
;
}
static void uart_tx_byte(unsigned char data)
{
uart_wait_to_tx_byte();
outb(data, TTYS0_BASE + UART_TBR);
/* Make certain the data clears the fifos */
uart_wait_until_sent();
}
void uart_init(void)
{
/* disable interrupts */
outb(0x0, TTYS0_BASE + UART_IER);
/* enable fifo's */
outb(0x01, TTYS0_BASE + UART_FCR);
/* Set Baud Rate Divisor to 12 ==> 115200 Baud */
outb(0x80 | UART_LCS, TTYS0_BASE + UART_LCR);
outb(TTYS0_DIV & 0xFF, TTYS0_BASE + UART_DLL);
outb((TTYS0_DIV >> 8) & 0xFF, TTYS0_BASE + UART_DLM);
outb(UART_LCS, TTYS0_BASE + UART_LCR);
}
void __console_tx_char(unsigned char byte)
{
uart_tx_byte(byte);
}
void __console_tx_string(char *str)
{
unsigned char ch;
while((ch = *str++) != '\0') {
__console_tx_char(ch);
}
}
void print_debug_char(unsigned char byte) { __console_tx_char(byte); }
void print_debug(char *str) { __console_tx_string(str); }
void main(void)
{
static const char msg[] = "hello world\r\n";
uart_init();
#if 0
print_debug(msg);
#endif
#if 1
print_debug("hello world\r\n");
print_debug("how are you today\r\n");
#endif
while(1) {
;
}
}
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