-
-/* If we include "Stg.h" directly, we're in STG code, and we therefore
- * get all the global register variables, macros etc. that go along
- * with that. If "Stg.h" is included via "Rts.h", we're assumed to
- * be in vanilla C.
+/*
+ * If we are compiling a .hc file, then we want all the register
+ * variables. This is the what happens if you #include "Stg.h" first:
+ * we assume this is a .hc file, and set IN_STG_CODE==1, which later
+ * causes the register variables to be enabled in stg/Regs.h.
+ *
+ * If instead "Rts.h" is included first, then we are compiling a
+ * vanilla C file. Everything from Stg.h is provided, except that
+ * IN_STG_CODE is not defined, and the register variables will not be
+ * active.