+#undef BYTE
+#define BYTE(p,n) (unsigned char)((p)[n])
+
+#define IS_NEG1(p) ((BYTE(p,0) == 0377) && (BYTE(p,1) == 0377))
+#define IS_NEG2(p) ((BYTE(p,0) == 0376) && (BYTE(p,1) == 0377))
+#define LOW_MSB(p) (BYTE(p,0) + 256*BYTE(p,1))
+
+#define IS_TIC_MAGIC(p) (LOW_MSB(p) == MAGIC)
+