diff --git a/include/rp6502.h b/include/rp6502.h
index b51382825..d40ba8a88 100644
--- a/include/rp6502.h
+++ b/include/rp6502.h
@@ -133,14 +133,14 @@ long __fastcall__ ria_call_long (unsigned char op);
 /* C API for the operating system. */
 
 typedef struct {
-    unsigned long fsize;    /* File size (invalid for directory) */
-    unsigned fdate;         /* Date of file modification or directory creation */
-    unsigned ftime;         /* Time of file modification or directory creation */
-    unsigned crdate;        /* Date of object createion */
-    unsigned crtime;        /* Time of object createion */
-    unsigned char fattrib;  /* Object attribute */
-    char altname[12 + 1];   /* Alternative object name */
-    char fname[255 + 1];    /* Primary object name */
+    unsigned long fsize;
+    unsigned fdate;
+    unsigned ftime;
+    unsigned crdate;
+    unsigned crtime;
+    unsigned char fattrib;
+    char altname[12 + 1];
+    char fname[255 + 1];
 } f_stat_t;
 
 int __cdecl__ xregn (char device, char channel, unsigned char address, unsigned count,
@@ -157,8 +157,11 @@ int __fastcall__ write_xram (unsigned buf, unsigned count, int fildes);
 long __fastcall__ f_lseek (long offset, int whence, int fildes);
 int __fastcall__ f_stat (const char* path, f_stat_t* dirent);
 int __fastcall__ f_opendir (const char* name);
-int __fastcall__ f_readdir (f_stat_t *dirent, int dirdes);
+int __fastcall__ f_readdir (f_stat_t* dirent, int dirdes);
 int __fastcall__ f_closedir (int dirdes);
+long __fastcall__ f_telldir (int dirdes);
+int __fastcall__ f_seekdir (long offs, int dirdes);
+int __fastcall__ f_rewinddir (int dirdes);
 
 
 /* Time zone hack */
diff --git a/libsrc/rp6502/f_closedir.c b/libsrc/rp6502/f_closedir.c
index 03239c874..279483ca9 100644
--- a/libsrc/rp6502/f_closedir.c
+++ b/libsrc/rp6502/f_closedir.c
@@ -1,5 +1,4 @@
 #include <rp6502.h>
-#include <fcntl.h>
 
 int __fastcall__ f_closedir (int dirdes)
 {
diff --git a/libsrc/rp6502/f_lseek.c b/libsrc/rp6502/f_lseek.c
index da7c3dfdf..ada9baab5 100644
--- a/libsrc/rp6502/f_lseek.c
+++ b/libsrc/rp6502/f_lseek.c
@@ -1,5 +1,4 @@
 #include <rp6502.h>
-#include <unistd.h>
 
 long __fastcall__ f_lseek (long offset, int whence, int fildes)
 {
diff --git a/libsrc/rp6502/f_readdir.c b/libsrc/rp6502/f_readdir.c
index f6fa42e1b..45777c221 100644
--- a/libsrc/rp6502/f_readdir.c
+++ b/libsrc/rp6502/f_readdir.c
@@ -1,8 +1,6 @@
 #include <rp6502.h>
-#include <errno.h>
-#include <string.h>
 
-int __fastcall__ f_readdir (f_stat_t *dirent, int dirdes)
+int __fastcall__ f_readdir (f_stat_t* dirent, int dirdes)
 {
     int i, ax;
     ria_set_ax (dirdes);
diff --git a/libsrc/rp6502/f_rewinddir.c b/libsrc/rp6502/f_rewinddir.c
new file mode 100644
index 000000000..bd2ebaa1b
--- /dev/null
+++ b/libsrc/rp6502/f_rewinddir.c
@@ -0,0 +1,7 @@
+#include <rp6502.h>
+
+int __fastcall__ f_rewinddir (int dirdes)
+{
+    ria_set_ax (dirdes);
+    return ria_call_int (RIA_OP_REWINDDIR);
+}
diff --git a/libsrc/rp6502/f_seekdir.c b/libsrc/rp6502/f_seekdir.c
new file mode 100644
index 000000000..5c6890e3d
--- /dev/null
+++ b/libsrc/rp6502/f_seekdir.c
@@ -0,0 +1,8 @@
+#include <rp6502.h>
+
+int __fastcall__ f_seekdir (long offs, int dirdes)
+{
+    ria_set_ax (dirdes);
+    ria_push_long (offs);
+    return ria_call_int (RIA_OP_SEEKDIR);
+}
diff --git a/libsrc/rp6502/f_telldir.c b/libsrc/rp6502/f_telldir.c
new file mode 100644
index 000000000..1396e0a88
--- /dev/null
+++ b/libsrc/rp6502/f_telldir.c
@@ -0,0 +1,7 @@
+#include <rp6502.h>
+
+long __fastcall__ f_telldir (int dirdes)
+{
+    ria_set_ax (dirdes);
+    return ria_call_long (RIA_OP_TELLDIR);
+}