1 files changed, 48 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/SNIP/fndislot.c b/reference/C/CONTRIB/SNIP/fndislot.c
new file mode 100755
index 0000000..2999596
--- /dev/null
+++ b/reference/C/CONTRIB/SNIP/fndislot.c
@@ -0,0 +1,48 @@
+/*
+**  Originally published as part of the MicroFirm Function Library
+**
+**  Copyright 1990, Robert B.Stout
+**
+**  Subset version released to the public domain, 1992
+**
+**  Function to locate an unused user interrupt vector.
+*/
+
+#ifdef __ZTC__
+ #include <int.h>
+#else
+ #include <dos.h>
+ #ifdef __TURBOC__
+  #define GETVECT getvect
+  #define FAR far
+  #define INTERRUPT interrupt
+ #else /* assume MSC */
+  #define GETVECT _dos_getvect
+  #define FAR _far
+  #define INTERRUPT _interrupt
+ #endif
+ #define FNULL (void (FAR *)())(0L)
+#endif
+
+unsigned findIslot(void)
+{
+#ifdef __ZTC__
+      unsigned int_no, seg, ofs;
+
+      for (int_no = 0x60; int_no < 0x6f; ++int_no)
+      {
+            int_getvector(int_no, &seg, &ofs);
+            if (0U == (seg | ofs))
+                  return int_no;
+      }
+#else /* MSC/BC/TC */
+      unsigned int_no;
+
+      for (int_no = 0x60; int_no < 0x6f; ++int_no)
+      {
+            if (FNULL != (void (FAR *)())GETVECT(int_no))
+                  return int_no;
+      }
+#endif
+      return 0;
+}