Made tcp_listen return the client IP address.

Together with the recent change to provide the inbound data buffer address and length to the TCP callback function as C parameters this change allows the TCP API to get along without any global variable :-)

inc/ip65.h

@@ -181,9 +181,9 @@ unsigned char __fastcall__ udp_send(const unsigned char* buf, unsigned int len,
 //         callback: Vector to call when data arrives on this connection
 //                   buf: Pointer to buffer with data received
 //                   len: -1 on close, otherwise length of data received
-// Output: 1 if an error occured, 0 otherwise
+// Output: IP address of the connected client, 0 on error
 //
-unsigned char __fastcall__ tcp_listen(unsigned int port,
+unsigned long __fastcall__ tcp_listen(unsigned int port,
                                       void (*callback)(const unsigned char* buf, int len));
 
 // Make outbound TCP connection

ip65/tcp_c.s

@@ -15,6 +15,7 @@
 .import tcp_send_keep_alive
 
 .import tcp_callback
+.import tcp_remote_ip
 .import tcp_connect_ip
 .import tcp_send_data_len
 
@@ -40,9 +41,16 @@ _tcp_listen:
   stax tcp_callback
   jsr popax
   jsr tcp_listen
+  bcs error
+  ldax tcp_remote_ip+2
+  stax sreg
+  ldax tcp_remote_ip
+  rts
+
+error:
   ldx #$00
   txa
-  rol
+  stax sreg
   rts
 
 _tcp_connect: