From: whitequark <whitequark@whitequark.org>
Date: Sat, 15 Dec 2018 20:58:06 +0000 (+0000)
Subject: back.pysim: implement Part.
X-Git-Tag: working~214
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=20a04bca882fe7d56085a475a6bd556fba559713;p=nmigen.git

back.pysim: implement Part.
---

diff --git a/nmigen/back/pysim.py b/nmigen/back/pysim.py
index a3c09d1..e42169f 100644
--- a/nmigen/back/pysim.py
+++ b/nmigen/back/pysim.py
@@ -118,7 +118,11 @@ class _RHSValueCompiler(ValueTransformer):
         return lambda state: normalize((arg(state) >> shift) & mask, shape)
 
     def on_Part(self, value):
-        raise NotImplementedError
+        shape = value.shape()
+        arg   = self(value.value)
+        shift = self(value.offset)
+        mask  = (1 << value.width) - 1
+        return lambda state: normalize((arg(state) >> shift(state)) & mask, shape)
 
     def on_Cat(self, value):
         shape  = value.shape()
diff --git a/nmigen/hdl/ast.py b/nmigen/hdl/ast.py
index 42923f4..0ed355b 100644
--- a/nmigen/hdl/ast.py
+++ b/nmigen/hdl/ast.py
@@ -405,7 +405,7 @@ class Part(Value):
         return self.value._lhs_signals()
 
     def _rhs_signals(self):
-        return self.value._rhs_signals()
+        return self.value._rhs_signals() | self.offset._rhs_signals()
 
     def __repr__(self):
         return "(part {} {} {})".format(repr(self.value), repr(self.offset), self.width)
diff --git a/nmigen/test/test_sim.py b/nmigen/test/test_sim.py
index 7cecfd7..75e53a6 100644
--- a/nmigen/test/test_sim.py
+++ b/nmigen/test/test_sim.py
@@ -130,6 +130,12 @@ class SimulatorUnitTestCase(FHDLTestCase):
         stmt2 = lambda a: a[2:4]
         self.assertOperator(stmt2, [C(0b10110100, 8)], C(0b01, 2))
 
+    def test_part(self):
+        stmt = lambda a, b: a.part(b, 3)
+        self.assertOperator(stmt, [C(0b10110100, 8), C(0)], C(0b100, 3))
+        self.assertOperator(stmt, [C(0b10110100, 8), C(2)], C(0b101, 3))
+        self.assertOperator(stmt, [C(0b10110100, 8), C(3)], C(0b110, 3))
+
     def test_cat(self):
         self.assertOperator(Cat, [C(0b10, 2), C(0b01, 2)], C(0b0110, 4))