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#include "gbos.h"
/* necho: send a SLIP-framed packet over the link port and print the reply.
Talks to a host gateway (tools/gateway.py) that echoes frames back. */
#define SLIP_END 0xC0
#define SLIP_ESC 0xDB
#define SLIP_ESC_END 0xDC
#define SLIP_ESC_ESC 0xDD
static void slip_send(const char *buf, unsigned char len) {
unsigned char i, c;
ssend(SLIP_END);
for (i = 0; i < len; i++) {
c = (unsigned char)buf[i];
if (c == SLIP_END) { ssend(SLIP_ESC); ssend(SLIP_ESC_END); }
else if (c == SLIP_ESC) { ssend(SLIP_ESC); ssend(SLIP_ESC_ESC); }
else ssend(c);
}
ssend(SLIP_END);
}
static unsigned char slip_recv(char *buf, unsigned char max) {
unsigned char len = 0, c;
for (;;) {
c = srecv();
if (c == SLIP_END) { if (len) return len; continue; }
if (c == SLIP_ESC) {
c = srecv();
if (c == SLIP_ESC_END) c = SLIP_END;
else if (c == SLIP_ESC_ESC) c = SLIP_ESC;
}
if (len < max) buf[len++] = (char)c;
}
}
void main(void) {
char buf[64];
unsigned char len;
puts("net: send 'hello from gbos'"); nl();
slip_send("hello from gbos", 15);
len = slip_recv(buf, 63);
buf[len] = 0;
puts("net: recv '"); puts(buf); puts("'"); nl();
}
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