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sim._pyrtl: sign extend RHS of assignment.

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Fixes #502.
This commit is contained in:
whitequark 2020-10-22 16:08:38 +00:00
parent 9d62cbefa5
commit df70aae887
2 changed files with 9 additions and 1 deletions
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5
nmigen/sim/_pyrtl.py
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@ -337,7 +337,10 @@ class _StatementCompiler(StatementVisitor, _Compiler):
self.emitter.append("pass") self.emitter.append("pass")
def on_Assign(self, stmt): def on_Assign(self, stmt):
return self.lhs(stmt.lhs)(self.rhs(stmt.rhs)) gen_rhs = f"({(1 << len(stmt.rhs)) - 1} & {self.rhs(stmt.rhs)})"
if stmt.rhs.shape().signed:
gen_rhs = f"sign({gen_rhs}, {-1 << (len(stmt.rhs) - 1)})"
return self.lhs(stmt.lhs)(gen_rhs)
def on_Switch(self, stmt): def on_Switch(self, stmt):
gen_test = self.emitter.def_var("test", gen_test = self.emitter.def_var("test",

5
tests/test_sim.py
View file

@ -67,6 +67,11 @@ class SimulatorUnitTestCase(FHDLTestCase):
self.assertStatement(stmt, [C(0b01, unsigned(2)), C(0b0001, signed(4))], C(1)) self.assertStatement(stmt, [C(0b01, unsigned(2)), C(0b0001, signed(4))], C(1))
self.assertStatement(stmt, [C(0b11, unsigned(2)), C(0b1111, signed(4))], C(1)) self.assertStatement(stmt, [C(0b11, unsigned(2)), C(0b1111, signed(4))], C(1))
def test_as_signed_issue_502(self):
stmt = lambda y, a: y.eq(a.as_signed())
self.assertStatement(stmt, [C(0b01, unsigned(2))], C(0b0001, signed(4)))
self.assertStatement(stmt, [C(0b11, unsigned(2))], C(0b1111, signed(4)))
def test_any(self): def test_any(self):
stmt = lambda y, a: y.eq(a.any()) stmt = lambda y, a: y.eq(a.any())
self.assertStatement(stmt, [C(0b00, 2)], C(0)) self.assertStatement(stmt, [C(0b00, 2)], C(0))