debugged _len attr to intbv constructors

added test for bounds inferred by getslice

myhdl/intbv.py

@@ -82,10 +82,10 @@ class intbv(object):
                 width += w
             else:
                 raise TypeError
-        res = intbv(v)
         if basewidth:
-            res._len = basewidth + width
-        return res
+            return intbv(v, _len=basewidth + width)
+        else:
+            return intbv(v)
 
     # hash
     def __hash__(self):
@@ -113,8 +113,7 @@ class intbv(object):
     # indexing and slicing methods
 
     def __getitem__(self, i):
-        res = intbv((self._val >> i) & 0x1)
-        res._len = 1
+        res = intbv((self._val >> i) & 0x1, _len=1)
         return res
 
     def __getslice__(self, i, j):
@@ -128,8 +127,7 @@ class intbv(object):
         if i <= j:
             raise ValueError, "intbv[i:j] requires i > j\n" \
                   "            i, j == %s, %s" % (i, j)
-        res = intbv((self._val & 2**i-1) >> j)
-        res._len = i-j
+        res = intbv((self._val & 2**i-1) >> j, _len=i-j)
         return res
         
     def __setitem__(self, i, val):

myhdl/test_all.py

@@ -24,9 +24,10 @@ __revision__ = "$Revision$"
 __date__ = "$Date$"
 
 import test_Simulation, test_Signal, test_intbv, test_Cosimulation, test_misc, \
-       test_always_comb
+       test_always_comb, test_intbvbounds
 
-modules = (test_Simulation, test_Signal, test_intbv, test_misc, test_always_comb)
+modules = (test_Simulation, test_Signal, test_intbv, test_misc, test_always_comb,
+           test_intbvbounds)
 
 import unittest
 

myhdl/test_intbvbounds.py

@@ -66,6 +66,17 @@ class TestIntbvBounds(TestCase):
                 pass
             else:
                 self.fail()
+        a = intbv(5)[8:]
+        a[:] = 0
+        a[:] = 2**8-1
+        try:
+            a[:] = -1
+            a[:] = 2**8
+        except ValueError:
+            pass
+        else:
+            self.fail()
+            
 
 
     def checkBounds(self, i, j, op):