diff --git a/targettest/cbm/Makefile b/targettest/cbm/Makefile
index fb7af1a9a..298f80d62 100644
--- a/targettest/cbm/Makefile
+++ b/targettest/cbm/Makefile
@@ -30,10 +30,13 @@ else
   LD := $(if $(wildcard ../../../bin/ld65*),../../../bin/ld65,ld65)
 endif
 
-all: petscii.prg
+all: petscii.prg cbmdir-test.prg
 
 petscii.prg: petscii.c
 	$(CL) -t $(SYS) -O -o petscii.prg petscii.c
 
+cbmdir-test.prg: cbmdir-test.c
+	$(CL) -t $(SYS) -Oris -o $@ $<
+
 clean:
-	@$(DEL) petscii.prg 2>$(NULLDEV)
+	@$(DEL) petscii.prg cbmdir-test.prg 2>$(NULLDEV)
diff --git a/targettest/cbm/cbmdir-test.c b/targettest/cbm/cbmdir-test.c
new file mode 100644
index 000000000..0db9856b7
--- /dev/null
+++ b/targettest/cbm/cbmdir-test.c
@@ -0,0 +1,119 @@
+/*
+** Tests the CBM-specific directory functions.
+**
+** 2021-08-12, Greg King
+*/
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <conio.h>
+#include <cbm.h>
+
+
+/* device number */
+#define UNIT 8
+
+/* directory patterm */
+static const char name[] = "$";
+
+
+static const char* const type[] = {
+    "DEL",
+    "CBM",
+    "DIR",
+    "LNK",
+    "???",
+    "Directory header",
+    "",
+    "",
+    "",
+    "",
+    "",
+    "",
+    "",
+    "",
+    "",
+    "",
+    "SEQ",
+    "PRG",
+    "USR",
+    "REL",
+    "VRP"
+};
+
+static const char* const access[] = {
+    "unknown",
+    "read-only",
+    "write-only",
+    "read/write"
+};
+
+static const char* const error[] = {
+    "",
+    "couldn't read it",
+    "",
+    "couldn't find start of file-name",
+    "couldn't find end of file-name",
+    "couldn't read file-type",
+    "premature end of file"
+};
+
+
+int main(void)
+{
+    unsigned char go = 0;
+    unsigned char rc;
+    struct cbm_dirent E;
+
+    /* Explain use, and wait for a key. */
+    printf ("use the following keys:\n"
+            "  g -> go ahead without stopping\n"
+            "  q -> quit directory lister\n"
+            "tap any key to start ...\n\n");
+    cgetc ();
+
+    /* Open the directory. */
+    if (cbm_opendir (1, UNIT, name) != 0) {
+        printf("error opening %s:\n %s\n", name, _stroserror (_oserror));
+        return 1;
+    }
+
+    /* Output the directory. */
+    printf("contents of \"%s\":\n", name);
+    while ((rc = cbm_readdir (1, &E)) != 2) {
+        if (rc != 0) {
+            goto oops;
+        }
+
+        printf (" name[]: \"%s\"\n", E.name);
+        printf (" size  :%6u\n",     E.size);
+        printf (" type  : %s\n",     type[E.type]);
+        printf (" access: %s\n",     access[E.access > 3 ? 0 : E.access]);
+        printf ("----\n");
+
+        if (!go) {
+            switch (cgetc ()) {
+              case 'q':
+                goto done;
+
+              case 'g':
+                go = 1;
+            }
+        }
+    }
+
+    printf (" size  :%6u free.\n", E.size);
+
+done:
+    /* Close the directory. */
+    cbm_closedir (1);
+    return 0;
+
+oops:
+    if (rc <= 6) {
+        printf ("\ndirectory error:\n %s.\n", error[rc]);
+    }
+    cbm_closedir (1);
+    return 1;
+}