Doc C language guidelines.

diff --git a/sim/README-HACKING b/sim/README-HACKING
index 21c34f625fd73fef112307e19e2373cdaa9a4af9..fd6aae19f91f284a35208760c4cbaef1a9ded173 100644 (file)
--- a/sim/README-HACKING
+++ b/sim/README-HACKING
@@ -162,3 +162,27 @@ For a list of all of them, see common/tconfig.in.
 It contains them all, commented out.
 The intent is that a new port can just copy this file and
 define the ones it needs.
+\f
+C Language Assumptions
+======================
+
+The programmer may assume that the simulator is being built using an
+ANSI C compiler that supports a 64 bit data type.  Consequently:
+
+       o       prototypes can be used (although using
+               PARAMS() and K&R declarations wouldn't
+               go astray).
+
+       o       If sim-types.h is included, the two
+               types signed64 and unsigned64 are
+               available.
+
+       o       The type `unsigned' is valid.
+
+However, the user should not assume:
+
+       o       `<number>LL' is acceptable.  Microsoft-C
+               doesn't reconize it.
+
+       o       `long long' or `_int64' provides a 64 bit
+               integer data type.