From 78dc0cb7b421036a5df431b9e286b2d1cbf03584 Mon Sep 17 00:00:00 2001
From: jand <none@none>
Date: Wed, 2 Jul 2003 08:01:14 +0000
Subject: [PATCH] set slice with left index open implementation and test

---
 myhdl/intbv.py      |  8 ++++----
 myhdl/test_intbv.py | 29 +++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/myhdl/intbv.py b/myhdl/intbv.py
index 177f5d97..13c29060 100644
--- a/myhdl/intbv.py
+++ b/myhdl/intbv.py
@@ -121,10 +121,10 @@ class intbv(object):
     def __setslice__(self, i, j, val):
         if j == maxint: # default
             j = 0
-##         if i == 0: # default
-##             q = self._val % (2**j)
-##             self._val = val * 2**j + q
-##             return
+        if i == 0: # default
+            q = self._val % (2**j)
+            self._val = val * 2**j + q
+            return
         if i <= j or i < 1 or j < 0:
             raise ValueError, "intbv[i:j] = v: requires i > j >= 0" \
                   "            i, j ,v == %s, %s %s" % (i, j, val)
diff --git a/myhdl/test_intbv.py b/myhdl/test_intbv.py
index 059cfd21..babf817a 100644
--- a/myhdl/test_intbv.py
+++ b/myhdl/test_intbv.py
@@ -123,6 +123,14 @@ def setSlice(s, i, j, val):
     si = len(exts)-i
     sj = len(exts)-j
     return exts[:si] + val[si-sj:] + exts[sj:]
+
+def setSliceLeftOpen(s, j, val):
+    ext = '0' * (j-len(s)+1)
+    exts = ext + s
+    if j:
+        return val + exts[-j:]
+    else:
+        return val
     
 
 class TestIntBvIndexing(TestCase):
@@ -250,6 +258,27 @@ class TestIntBvIndexing(TestCase):
                             refi = ~long(setSlice(s, i, j, extv), 2)
                             self.assertEqual(bvi, refi)
                             
+    def testSetSliceLeftOpen(self):
+        self.seqsSetup()
+        toggle = 0 
+        for s in self.seqs:
+            n = long(s, 2)
+            for j in range(0, len(s)+5):
+                for v in self.seqv:
+                    bv = intbv(n)
+                    bvi = intbv(~n)
+                    val = long(v, 2)
+                    toggle ^= 1
+                    if toggle:
+                        val = intbv(val)
+                    bv[:j] = val
+                    bvi[:j] = -1-val
+                    ref = long(setSliceLeftOpen(s, j, v), 2)
+                    self.assertEqual(bv, ref)
+                    refi = ~long(setSliceLeftOpen(s, j, v), 2)
+                    self.assertEqual(bvi, refi)
+    
+                            
 
 class TestIntBvAsInt(TestCase):