[PATCH v1 06/36] Guile extension language: gdbtypes.c additions

[Doug Evans <xdje42@gmail.com>]

This patch adds two new functions that are used by the Guile routines.
I may change these to return a value, and split get_signed_type_minmax
into two.

2013-12-24  Doug Evans  <xdje42@gmail.com>

	* gdbtypes.c (get_unsigned_type_max): New function.
	(get_signed_type_minmax): New function.
	* gdbtypes.h (get_unsigned_type_max): Declare.
	(get_signed_type_minmax): Declare.

diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 2470304..2235594 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -1446,6 +1446,40 @@ lookup_struct_elt_type (struct type *type, const char *name, int noerr)
   error (_("Type %s has no component named %s."), typename, name);
 }
 
+/* Store in *MAX the largest number representable by unsigned integer type
+   TYPE.  */
+
+void
+get_unsigned_type_max (struct type *type, ULONGEST *max)
+{
+  unsigned int n;
+
+  CHECK_TYPEDEF (type);
+  gdb_assert (TYPE_CODE (type) == TYPE_CODE_INT && TYPE_UNSIGNED (type));
+  gdb_assert (TYPE_LENGTH (type) <= sizeof (ULONGEST));
+
+  /* Written this way to avoid overflow.  */
+  n = TYPE_LENGTH (type) * TARGET_CHAR_BIT;
+  *max = ((((ULONGEST) 1 << (n - 1)) - 1) << 1) | 1;
+}
+
+/* Store in *MIN, *MAX the smallest and largest numbers representable by
+   signed integer type TYPE.  */
+
+void
+get_signed_type_minmax (struct type *type, LONGEST *min, LONGEST *max)
+{
+  unsigned int n;
+
+  CHECK_TYPEDEF (type);
+  gdb_assert (TYPE_CODE (type) == TYPE_CODE_INT && !TYPE_UNSIGNED (type));
+  gdb_assert (TYPE_LENGTH (type) <= sizeof (LONGEST));
+
+  n = TYPE_LENGTH (type) * TARGET_CHAR_BIT;
+  *min = -((ULONGEST) 1 << (n - 1));
+  *max = ((ULONGEST) 1 << (n - 1)) - 1;
+}
+
 /* Lookup the vptr basetype/fieldno values for TYPE.
    If found store vptr_basetype in *BASETYPEP if non-NULL, and return
    vptr_fieldno.  Also, if found and basetype is from the same objfile,
diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index c7bef5f..2814ca1 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -1545,6 +1545,10 @@ extern struct type *lookup_unsigned_typename (const struct language_defn *,
 extern struct type *lookup_signed_typename (const struct language_defn *,
 					    struct gdbarch *, const char *);
 
+extern void get_unsigned_type_max (struct type *, ULONGEST *);
+
+extern void get_signed_type_minmax (struct type *, LONGEST *, LONGEST *);
+
 extern struct type *check_typedef (struct type *);
 
 #define CHECK_TYPEDEF(TYPE)			\