--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sw/mcsi-rxtx/mainloop.c	Mon Oct 28 01:44:28 2024 +0000
@@ -0,0 +1,70 @@
+/*
+ * This module holds our main loop code, factored out into a separate
+ * function that is called from main() after initialization.
+ */
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+extern int target_fd;
+
+main_loop()
+{
+	fd_set fds;
+	struct timeval tv;
+	u_char buf[320];
+	unsigned off;
+	int cc, is_active;
+
+	is_active = 0;
+	off = 0;
+	for (;;) {
+		FD_ZERO(&fds);
+		FD_SET(0, &fds);
+		FD_SET(target_fd, &fds);
+		if (is_active) {
+			tv.tv_sec = 0;
+			tv.tv_usec = 100000;
+			cc = select(target_fd+1, &fds, 0, 0, &tv);
+		} else
+			cc = select(target_fd+1, &fds, 0, 0, 0);
+		if (cc < 0) {
+			if (errno == EINTR)
+				continue;
+			perror("select");
+			exit(1);
+		}
+		if (cc == 0) {
+			is_active = 0;
+			printf("Rx stream stopped, buffer dribble = %u\n", off);
+			off = 0;
+			continue;
+		}
+		if (FD_ISSET(0, &fds))
+			handle_tty_input();
+		if (FD_ISSET(target_fd, &fds)) {
+			cc = read(target_fd, buf + off, sizeof(buf) - off);
+			if (cc < 0) {
+				perror("serial port read");
+				exit(1);
+			}
+			if (cc == 0) {
+				fprintf(stderr, "read EOF from serial port\n");
+				exit(1);
+			}
+			if (!is_active) {
+				printf("Rx stream started\n");
+				is_active = 1;
+			}
+			off += cc;
+			if (off >= sizeof(buf)) {
+				process_rx_block(buf);
+				off = 0;
+			}
+		}
+	}
+}