Add support for COM3 & COM4 (#22)

Author: benjamink

README.md

@@ -5,8 +5,8 @@ Code for FujiNet RS-232 Version
 
 The current code which is built against FUJICOM reacts to the following environment variables
 
-| Variable  | Default | Description                     |
-|-----------|---------|---------------------------------|
-| FUJI_PORT | 1       | The Serial port to use, 1 or 2. |
-| FUJI_BAUD | 9600    | The Baud rate to use.           |
+| Variable  | Default | Description                         |
+|-----------|---------|-------------------------------------|
+| FUJI_PORT | 1       | The Serial port to use, 1, 2, 3, 4. |
+| FUJI_BAUD | 9600    | The Baud rate to use.               |
 

fujicom/com.h

@@ -76,12 +76,16 @@ extern int port_identify_uart(PORT far *port);
 
 /*
  * These are the standard UART addresses and interrupt
- * numbers for the two IBM compatible COM ports.
+ * numbers for the four IBM compatible COM ports.
  */
 #define COM1_UART         0x3f8
 #define COM1_INTERRUPT    12
 #define COM2_UART         0x2f8
 #define COM2_INTERRUPT    11
+#define COM3_UART         0x3e8
+#define COM3_INTERRUPT    12
+#define COM4_UART         0x2e8
+#define COM4_INTERRUPT    11
 
 enum {
   UART_8250 = 0,

fujicom/fujicom.c

@@ -54,6 +54,14 @@ void fujicom_init(void)
     base = COM2_UART;
     irq = COM2_INTERRUPT;
     break;
+  case 3:
+    base = COM3_UART;
+    irq = COM3_INTERRUPT;
+    break;
+  case 4:
+    base = COM4_UART;
+    irq = COM4_INTERRUPT;
+    break;
   }
 
   port = port_open(&fn_port, base, irq);

sys/commands.c

@@ -196,7 +196,7 @@ uint16_t Output_cmd(SYSREQ far *req)
     return ERROR_BIT | UNKNOWN_UNIT;
   }
 
-  if (disk_slots[req->unit].mode != MODE_READWRITE)
+  if (disk_slots[req->unit].mode != SLOT_READWRITE)
     return ERROR_BIT | WRITE_PROTECT;
 
   if (req->length > 22)