#define UARTADDRESS (unsigned int *)0xf0000100
#define REFFREQ	50000000

volatile unsigned int* _uartaddr = UARTADDRESS;
volatile unsigned int _uartstate;

/*
	地址 0 -- 读接收数据
		 1 -- 写发送数据
		 2 -- 得到状态
		   [0]		-- send buffer ready
		   [10:1]	-- send buffer used
		   [16]		-- recv buffer ready
		   [26:17]	-- recv buffer used
*/

int _canputchar()
{
	_uartstate = _uartaddr[2];
	return ((_uartstate & 1) == 0);
}

int _haschar()
{
	_uartstate = _uartaddr[2];
	return ((_uartstate & 0x10000) == 0);
}

int _putchar(int ch)
{
	_uartstate = _uartaddr[2];
	if ((_uartstate & 1) == 0) {
		_uartaddr[1] = ch;
		return 0;
	}
	return -1;
}

int _getchar()
{
	_uartstate = _uartaddr[2];
	if ((_uartstate & 0x10000) == 0) {
		return _uartaddr[0];
	}
	return -1;
}

int _puts(char* s)
{
	while (*s) {
		while (_putchar(*s) == -1)
			;
		s++;
	}
	return 0;
}

int _gets(char* s, int buflen)
{
	int ind, ch;
	ind = 0;
	if (buflen <= 1)
		return 0;
	do {
		ch = _getchar();
		if (ch != -1) {
			s[ind++] = ch;
			while(_putchar(ch) == -1) /* 回显 */
				;
			if (ind >= buflen - 1)
				break;
			if (ch == '\n' || ch == '\r')
				break;
		}
	} while (1);
	s[ind] = 0;
	return ind;
}

int _d2s(char* buf, int num)
{
	int i;
	int len;
	int sign;
	len = 0;
	sign = 0;
	if (num < 0) {
		num = -num;
		sign = 0;
	}
	while (num > 0) {
		buf[len++] = (num % 10) + '0';
		num /= 10;
	}
	if (sign)
		buf[len++] = '-';
	for (i = 0; i < len / 2; i++) {
		int di = len - 1 - i;
		char temp;
		temp = buf[i];
		buf[i] = buf[di];
		buf[di] = temp;
	}
	buf[len] = 0;
	return len;
}

int _h2s(char* buf, unsigned int num, int fixlen, char lead)
{
	int i;
	int len;
	len = 0;
	while (num > 0) {
		int n = num & 0xf;
		if (n < 10)
			buf[len] = n + '0';
		else
			buf[len] = n + 'a' - 10;
		num >>= 4;
		len++;
	}
	while (len < fixlen) {
		buf[len++] = lead;
	}
	for (i = 0; i < len / 2; i++) {
		int di = len - 1 - i;
		char temp;
		temp = buf[i];
		buf[i] = buf[di];
		buf[di] = temp;
	}
	buf[len] = 0;
	return len;
}

int _s2d(char* buf, char** next)
{
	int state;
	int ret;
	int sign;
	state = 0;
	ret = 0;
	sign = 1;
	while (*buf) {
		int ch;
		ch = *buf;
		if (ch >= '0' && ch <= '9') {
			ret = ret * 10 + ch - '0';
			state = 1;
		}
		else {
			if (state == 0) {
				if (ch == '-') {
					sign = -1;
					state = 1;
				}
			}
			else {
				break;
			}
		}
		buf++;
	}
	ret *= sign;
	if (next != 0) {
		*next = buf;
	}
	return ret;
}

int _s2h(char* buf, char** next)
{
	int state;
	int ret;
	state = 0;
	ret = 0;
	while (*buf) {
		int ch;
		ch = *buf;
		if (ch >= '0' && ch <= '9') {
			state = 1;
			ret = (ret << 4) + ch - '0';
		}
		else if (ch >= 'a' && ch <= 'f') {
			state = 1;
			ret = (ret << 4) + ch - 'a' + 10;
		}
		else if (ch >= 'A' && ch <= 'F') {
			state = 1;
			ret = (ret << 4) + ch - 'A' + 10;
		}
		else {
			if (state == 0)
				state = 1;
			else
				break;
		}
		buf++;
	}
	if (next != 0) {
		*next = buf;
	}
	return ret;
}

int _strlen(char* s)
{
	char* ss;
	ss = s;
	while (*s) s++;
	return s - ss;
}

int _strcpy(char* s, const char* t)
{
	char* ss = s;
	while (*t)
		*s++ = *t++;
	*s = 0;
	return s - ss;
}

int _strcat(char* s, const char* t)
{
	char* ss = s;
	while (*s)
		s++;
	while (*t)
		*s++ = *t++;
	*s = 0;
	return s - ss;
}

int _strcmp(char* s, const char* t)
{
	while (*s && *t) {
		if (*s++ != *t++)
			return 1;
	}
	return 0;
}

int _strncmp(char* s, const char* t, int n)
{
	int count;
	count = 0;
	while (*s && *t) {
		if (*s++ != *t++)
			return 1;
		count++;
		if (count >= n)
			return 0;
	}
	return 0;
}

int _buadrateset(int baud)
{
	_uartaddr[4] = REFFREQ / baud;
	return 0;
}

unsigned int displayaddr = 0;
void dispmem()
{
	int i, j, len;
	unsigned int startaddr = displayaddr & 0xfffffff0;
	char buf[256];
	for (j = 0; j < 16; j++) {
		_h2s(buf, startaddr, 8, '0');
		len = _strcat(buf, "  ");
		for (i = 0; i < 16; i++) {
			unsigned char* disp = (unsigned char*)startaddr;
			if (startaddr + i < displayaddr) {
				len = _strcat(buf, "   ");
			}
			else {
				char temp[8];
				_h2s(temp, disp[i], 2, '0');
				_strcat(temp, " ");
				len = _strcat(buf, temp);
			}
			if (i == 7)
				_strcat(buf, "- ");
		}
		_strcat(buf, "  |");
		for (i = 0; i < 16; i++) {
			unsigned char* disp = (unsigned char*)startaddr;
			char temp[2];
			if (disp[i] > 0x20 && disp[i] < 0x7f) {
				temp[0] = disp[i];
			}
			else {
				temp[0] = '.';
			}
			temp[1] = 0;
			_strcat(buf, temp);
		}
		_strcat(buf, "|\n");
		_puts(buf);
		startaddr += 16;
		if ( (startaddr & 0xff) == 0)
			break;
	}
	_puts("\n");
	displayaddr = startaddr;
}

int main(int argc, char* argv[])
{
	_buadrateset(115200);
	_puts("Hello, World\n");
	do {
		char buf[256];
		_puts(">>");
		_gets(buf, 255);
		_puts(":");
		_puts(buf);
		if (_strncmp(buf, "help ", 4) == 0) {
			_puts("  d <addr> -- display memory \n");
			_puts("  b <baudrate> -- set baudrate \n");
		}
		else if (_strncmp(buf, "b", 1) == 0) {
			int baud = _s2d(buf+2, 0);
			if (baud > 0) {
				_buadrateset(baud);
			}
		}
		else if (_strncmp(buf, "d", 1) == 0) {
			int addr = _s2h(buf + 2, 0);
			if (addr > 0) {
				displayaddr = addr;
			}
			dispmem();	
		}
	} while (1);
	return 1;
}