Add pcdrv stub + ref

pcdrv.c

@@ -0,0 +1,80 @@
+int waitForSIODone( int command ){
+    
+    // This should wait for a signal from the SIO to send when it's done  
+    // command can be 0 open, 1 close, 2 seek, 3 read, 4 write
+    // Returns val < 0 if wrong
+
+};
+
+#define OPEN   0
+#define CLOSE  1 
+#define SEEK   2
+#define READ   3
+#define WRITE  4
+#define CREATE 5
+
+int open(const char * filename, int attributes) {
+    
+  // Send filename and attributes (ro,wo,rw..)
+  // expects an int referring to a file descriptor on the PC 
+
+  int fd = 0; // File Descriptor https://en.wikipedia.org/wiki/File_descriptor
+
+  printf("open:%s:%i:%08x", filename, attributes, &fd);
+  
+  waitForSIODone(0)
+  
+  return fd; // If all is well, returns a positive int . If -1, wrong
+
+};
+
+int create(const char * filename, int attributes) {
+    
+  // Send filename and attributes (ro,wo,rw..)
+  // expects an int referring to a file descriptor on the PC 
+
+  int fd = 0; // File Descriptor https://en.wikipedia.org/wiki/File_descriptor
+
+  printf("create:%s:%i:%08x", filename, attributes, &fd);
+  
+  waitForSIODone(5); // Should return int fd, -1 else
+  
+  return fd; // If all is well, returns a positive int . If -1, wrong
+
+};
+
+int close( int fd ) {
+  
+  // Send the close command and fd as int
+
+  printf("close:%s:%08x", filename, fd);
+  
+  return waitForSIODone(1); // Should return 1 if ok, 0 if wrong, or -1 if wrong ?
+
+};
+
+int seek( int fd, int offset, int accessMode){
+  
+  // Move file pointer in fd at offset
+  // Access mode can be 0 abs, 1 rel to start, 2 rel to end 
+
+  printf("seek:%i:%08x:%i", fd, offset, accessMode);
+  
+  return waitForSIODone(2);
+    
+};
+
+int read( int fd, int len, char * buffer ){
+  
+  // Read len bytes of fd and put them in buff
+
+  int count = 0;
+
+  printf("read:%i:%08x:%i", fd, len, buffer, count);
+  
+  waitForSIODone(3);
+  
+  return count;
+    
+};
+