really bad hack to fix simulator bug in carry handling

[soc.git] / src / soc / decoder / selectable_int.py

diff --git a/src/soc/decoder/selectable_int.py b/src/soc/decoder/selectable_int.py
index 4e091ea3d05f354d17571b1f3afa208423587af1..8eabec3ed08597ab5b601beed9e042cd396ddb10 100644 (file)
--- a/src/soc/decoder/selectable_int.py
+++ b/src/soc/decoder/selectable_int.py
@@ -153,7 +153,6 @@ class FieldSelectableIntTestCase(unittest.TestCase):
         fs[0:2] = 0b10
         self.assertEqual(fs.get_range(), 0b1011)
 
-
 class SelectableInt:
     """SelectableInt - a class that behaves exactly like python int
 
@@ -172,11 +171,22 @@ class SelectableInt:
         mask = (1 << bits) - 1
         self.value = value & mask
         self.bits = bits
+        self.overflow = (value & ~mask) != 0
 
     def eq(self, b):
         self.value = b.value
         self.bits = b.bits
 
+    def to_signed_int(self):
+        print ("to signed?", self.value & (1<<(self.bits-1)), self.value)
+        if self.value & (1<<(self.bits-1)) != 0: # negative
+            res = self.value - (1<<self.bits)
+            print ("    val -ve:", self.bits, res)
+        else:
+            res = self.value
+            print ("    val +ve:", res)
+        return res
+
     def _op(self, op, b):
         if isinstance(b, int):
             b = SelectableInt(b, self.bits)
@@ -245,7 +255,9 @@ class SelectableInt:
         return SelectableInt(~self.value, self.bits)
 
     def __neg__(self):
-        return SelectableInt(~self.value + 1, self.bits)
+        res = SelectableInt((~self.value) + 1, self.bits)
+        print ("neg", hex(self.value), hex(res.value))
+        return res
 
     def __lshift__(self, b):
         b = check_extsign(self, b)
@@ -277,7 +289,7 @@ class SelectableInt:
             start = self.bits - key.stop
 
             bits = stop - start
-            #print ("__getitem__ slice num bits", bits)
+            #print ("__getitem__ slice num bits", start, stop, bits)
             mask = (1 << bits) - 1
             value = (self.value >> start) & mask
             return SelectableInt(value, bits)
@@ -320,9 +332,9 @@ class SelectableInt:
         if isinstance(other, SelectableInt):
             other = check_extsign(self, other)
             assert other.bits == self.bits
-            other = other.value
+            other = other.to_signed_int()
         if isinstance(other, int):
-            return onebit(self.value >= other.value)
+            return onebit(self.to_signed_int() >= other)
         assert False
 
     def __le__(self, other):
@@ -331,9 +343,9 @@ class SelectableInt:
         if isinstance(other, SelectableInt):
             other = check_extsign(self, other)
             assert other.bits == self.bits
-            other = other.value
+            other = other.to_signed_int()
         if isinstance(other, int):
-            return onebit(self.value <= other)
+            return onebit(self.to_signed_int() <= other)
         assert False
 
     def __gt__(self, other):
@@ -342,20 +354,24 @@ class SelectableInt:
         if isinstance(other, SelectableInt):
             other = check_extsign(self, other)
             assert other.bits == self.bits
-            other = other.value
+            other = other.to_signed_int()
         if isinstance(other, int):
-            return onebit(self.value > other)
+            return onebit(self.to_signed_int() > other)
         assert False
 
     def __lt__(self, other):
+        print ("SelectableInt lt", self, other)
         if isinstance(other, FieldSelectableInt):
             other = other.get_range()
         if isinstance(other, SelectableInt):
             other = check_extsign(self, other)
             assert other.bits == self.bits
-            other = other.value
+            other = other.to_signed_int()
         if isinstance(other, int):
-            return onebit(self.value < other)
+            a = self.to_signed_int()
+            res = onebit(a  < other)
+            print ("    a < b", a, other, res)
+            return res
         assert False
 
     def __eq__(self, other):
@@ -366,6 +382,7 @@ class SelectableInt:
             other = check_extsign(self, other)
             assert other.bits == self.bits
             other = other.value
+        print ("    eq", other, self.value, other == self.value)
         if isinstance(other, int):
             return onebit(other == self.value)
         assert False