/* scan for the sequence $<data>#<checksum>. # will be replaced with \0.
* Returns NULL on disconnection. */
char *getpacket(void) {
char *buffer = &remcomInBuffer[0];
unsigned char checksum;
unsigned char xmitcsum;
int count;
char ch;
while (1) {
/* wait around for the start character, ignore all other characters */
do {
ch = get_debug_char();
if (ch == -1) // disconnected
return NULL;
} while (ch != '$');
retry:
checksum = 0;
xmitcsum = -1;
count = 0;
/* now, read until a # or end of buffer is found */
while (count < BUFMAX - 1) {
ch = get_debug_char();
if (ch == '$')
goto retry;
buffer[count] = ch;
if (ch == '#')
break;
count = count + 1;
checksum = checksum + ch;
}
if (ch == '#') {
buffer[count] = 0;
ch = get_debug_char();
xmitcsum = hex(ch) << 4;
ch = get_debug_char();
xmitcsum += hex(ch);
if (checksum != xmitcsum) {
put_debug_char('-'); /* failed checksum */
flush_out_buffer();
} else {
put_debug_char('+'); /* successful transfer */
/* if a sequence char is present, reply the sequence ID */
if(buffer[2] == ':') {
put_debug_char(buffer[0]);
put_debug_char(buffer[1]);
flush_out_buffer();
return &buffer[3];
}
flush_out_buffer();
return &buffer[0];
}
}
}
}
inline void DoSerial(void)
{
if (tx_tail!=tx_head)
{
if (put_debug_char(tx_buffer[tx_tail]))
tx_tail = (tx_tail+1)&(DBG_BUFFER_SIZE-1);
}
}
void DebugTask(void)
{
if (debug_char_rdy())
debug_rcv(get_debug_char());
else
debug_idle();
if (tx_tail!=tx_head)
{
if (put_debug_char(tx_buffer[tx_tail]))
tx_tail = (tx_tail+1)&(BUFFER_SIZE-1);
}
}
/* send the packet in buffer. */
static void putpacket(char *buffer) {
unsigned char checksum;
int count;
char ch;
/* $<packet info>#<checksum> */
do {
put_debug_char('$');
checksum = 0;
count = 0;
while ((ch = buffer[count])) {
put_debug_char(ch);
checksum += ch;
count += 1;
}
put_debug_char('#');
put_debug_char(hexchars[checksum >> 4]);
put_debug_char(hexchars[checksum & 0xf]);
flush_out_buffer();
ch = get_debug_char();
} while (ch != '+' && ch != -1);
}
