[pypy-svn] r62120 - pypy/trunk/pypy/lang/smalltalk

[tverwaes at codespeak.net]

Author: tverwaes
Date: Tue Feb 24 18:01:15 2009
New Revision: 62120

Modified:
   pypy/trunk/pypy/lang/smalltalk/primitives.py
Log:
making it a bit more sane. we still have to fix 0<<(too big) cases.


Modified: pypy/trunk/pypy/lang/smalltalk/primitives.py
==============================================================================
--- pypy/trunk/pypy/lang/smalltalk/primitives.py	(original)
+++ pypy/trunk/pypy/lang/smalltalk/primitives.py	Tue Feb 24 18:01:15 2009
@@ -183,7 +183,7 @@
         raise PrimitiveFailedError()
     return interp.space.wrap_int(receiver // argument)
     
-# #// -- return the result of a division, rounded towards negative infinity
+# #// -- return the result of a division, rounded towards negative infinite
 @expose_primitive(QUO, unwrap_spec=[int, int])
 def func(interp, receiver, argument):
     if argument == 0:
@@ -194,11 +194,26 @@
 @expose_primitive(BIT_SHIFT, unwrap_spec=[int, int])
 def func(interp, receiver, argument):
 
-    # left shift, must fail if we loose bits beyond 32
+    # TODO: 1 << 100 will overflow to 0. Catch this gracefully by Primitive
+    # Failing! Use ovfcheck_lfshift
+    # (http://codespeak.net/pypy/dist/pypy/doc/coding-guide.html#integer-types)
+
+    # left shift, must fail if we lose bits beyond 32
     if argument > 0:
         shifted = receiver << argument
-        if (shifted >> argument) != receiver:
-            raise PrimitiveFailedError()
+
+        # Make sure we respect our bitlimits set by TAGGED_XXXINT.
+        if shifted < 0:
+            # If negative, check if there are no bits unset outside the MAXINT
+            # region
+            if constants.TAGGED_MININT ^ shifted > constants.TAGGED_MAXINT:
+                raise PrimitiveFailedError()
+        else:
+            # If possitive, check if there are no bits set outside the MAXINT
+            # region
+            if shifted & constants.TAGGED_MAXINT != shifted:
+                raise PrimitiveFailedError()
+        
         return interp.space.wrap_int(shifted)
             
     # right shift, ok to lose bits