Let integers use up 2 tags to give them one extra bit and double their range.

* lisp.h (USE_2_TAGS_FOR_INTS): New macro.
(LISP_INT_TAG, case_Lisp_Int, LISP_STRING_TAG, LISP_INT_TAG_P): New macros.
(enum Lisp_Type): Use them.  Give explicit values.
(Lisp_Type_Limit): Remove.
(XINT, XUINT, make_number) [!USE_LISP_UNION_TYPE]:
(MOST_NEGATIVE_FIXNUM, MOST_POSITIVE_FIXNUM, INTMASK):
Pay attention to USE_2_TAGS_FOR_INTS.
(INTEGERP): Use LISP_INT_TAG_P.
* fns.c (internal_equal): Simplify the default case.
(sxhash): Use case_Lisp_Int.
* data.c (wrong_type_argument): Don't check against Lisp_Type_Limit any more.
(Ftype_of): Use case_Lisp_Int.
(store_symval_forwarding): Take into account the fact that Ints can
now have more than one tag.
* buffer.c (syms_of_buffer): Use LISP_INT_TAG.
buffer_slot_type_mismatch):
* xfaces.c (face_attr_equal_p):
* print.c (print_object):
* alloc.c (mark_maybe_object, mark_object, survives_gc_p): Use case_Lisp_Int.

1 files changed, 11 insertions, 7 deletions

diff --git a/src/data.c b/src/data.c
index fc50658dd7c..7110fb7eae7 100644
--- a/src/data.c
+++ b/src/data.c
@@ -108,10 +108,12 @@ Lisp_Object
 wrong_type_argument (predicate, value)
      register Lisp_Object predicate, value;
 {
-  /* If VALUE is not even a valid Lisp object, abort here
-     where we can get a backtrace showing where it came from.  */
-  if ((unsigned int) XTYPE (value) >= Lisp_Type_Limit)
-    abort ();
+  /* If VALUE is not even a valid Lisp object, we'd want to abort here
+     where we can get a backtrace showing where it came from.  We used
+     to try and do that by checking the tagbits, but nowadays all
+     tagbits are potentially valid.  */
+  /* if ((unsigned int) XTYPE (value) >= Lisp_Type_Limit)
+   *   abort (); */
 
   xsignal2 (Qwrong_type_argument, predicate, value);
 }
@@ -184,7 +186,7 @@ for example, (type-of 1) returns `integer'.  */)
 {
   switch (XTYPE (object))
     {
-    case Lisp_Int:
+    case_Lisp_Int:
       return Qinteger;
 
     case Lisp_Symbol:
@@ -975,8 +977,10 @@ store_symval_forwarding (symbol, valcontents, newval, buf)
             int offset = XBUFFER_OBJFWD (valcontents)->offset;
             Lisp_Object type = XBUFFER_OBJFWD (valcontents)->slottype;
 
-            if (! NILP (type) && ! NILP (newval)
-                && XTYPE (newval) != XINT (type))
+            if (!(NILP (type) || NILP (newval)
+                  || (XINT (type) == LISP_INT_TAG
+                      ? INTEGERP (newval)
+                      : XTYPE (newval) == XINT (type))))
               buffer_slot_type_mismatch (newval, XINT (type));
 
             if (buf == NULL)