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Add (heavily work in progress) documentation.

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To render correctly, the docs require:
 * pygments/pygments#1441
This commit is contained in:
whitequark 2020-04-27 07:21:31 +00:00
parent 8dacbbb2b2
commit 399b8f9863
21 changed files with 1565 additions and 23 deletions
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4
nmigen/hdl/ast.py
View file

@ -135,7 +135,7 @@ class Value(metaclass=ABCMeta):
self.src_loc = tracer.get_src_loc(1 + src_loc_at)
def __bool__(self):
raise TypeError("Attempted to convert nMigen value to boolean")
raise TypeError("Attempted to convert nMigen value to Python boolean")
def __invert__(self):
return Operator("~", [self])
@ -184,7 +184,7 @@ class Value(metaclass=ABCMeta):
# Neither Python nor HDLs implement shifts by negative values; prohibit any shifts
# by a signed value to make sure the shift amount can always be interpreted as
# an unsigned value.
raise NotImplementedError("Shift by a signed value is not supported")
raise TypeError("Shift amount must be unsigned")
def __lshift__(self, other):
other = Value.cast(other)
other.__check_shamt()

7
nmigen/hdl/dsl.py
View file

@ -214,10 +214,9 @@ class Module(_ModuleBuilderRoot, Elaboratable):
width, signed = cond.shape()
if signed:
warnings.warn("Signed values in If/Elif conditions usually result from inverting "
"Python booleans with ~, which leads to unexpected results: ~True is "
"-2, which is truthful. Replace `~flag` with `not flag`. (If this is "
"a false positive, silence this warning with "
"`m.If(x)` → `m.If(x.bool())`.)",
"Python booleans with ~, which leads to unexpected results. "
"Replace `~flag` with `not flag`. (If this is a false positive, "
"silence this warning with `m.If(x)` → `m.If(x.bool())`.)",
SyntaxWarning, stacklevel=4)
return cond

18
nmigen/test/test_hdl_ast.py
View file

@ -159,7 +159,7 @@ class ValueTestCase(FHDLTestCase):
def test_bool(self):
with self.assertRaises(TypeError,
msg="Attempted to convert nMigen value to boolean"):
msg="Attempted to convert nMigen value to Python boolean"):
if Const(0):
pass
@ -466,11 +466,11 @@ class OperatorTestCase(FHDLTestCase):
self.assertEqual(v1.shape(), unsigned(11))
def test_shl_wrong(self):
with self.assertRaises(NotImplementedError,
msg="Shift by a signed value is not supported"):
with self.assertRaises(TypeError,
msg="Shift amount must be unsigned"):
1 << Const(0, signed(6))
with self.assertRaises(NotImplementedError,
msg="Shift by a signed value is not supported"):
with self.assertRaises(TypeError,
msg="Shift amount must be unsigned"):
Const(1, unsigned(4)) << -1
def test_shr(self):
@ -479,11 +479,11 @@ class OperatorTestCase(FHDLTestCase):
self.assertEqual(v1.shape(), unsigned(4))
def test_shr_wrong(self):
with self.assertRaises(NotImplementedError,
msg="Shift by a signed value is not supported"):
with self.assertRaises(TypeError,
msg="Shift amount must be unsigned"):
1 << Const(0, signed(6))
with self.assertRaises(NotImplementedError,
msg="Shift by a signed value is not supported"):
with self.assertRaises(TypeError,
msg="Shift amount must be unsigned"):
Const(1, unsigned(4)) << -1
def test_lt(self):

12
nmigen/test/test_hdl_dsl.py
View file

@ -289,9 +289,9 @@ class DSLTestCase(FHDLTestCase):
m = Module()
with self.assertWarns(SyntaxWarning,
msg="Signed values in If/Elif conditions usually result from inverting Python "
"booleans with ~, which leads to unexpected results: ~True is -2, which is "
"truthful. Replace `~flag` with `not flag`. (If this is a false positive, "
"silence this warning with `m.If(x)` → `m.If(x.bool())`.)"):
"booleans with ~, which leads to unexpected results. Replace `~flag` with "
"`not flag`. (If this is a false positive, silence this warning with "
"`m.If(x)` → `m.If(x.bool())`.)"):
with m.If(~True):
pass
@ -301,9 +301,9 @@ class DSLTestCase(FHDLTestCase):
pass
with self.assertWarns(SyntaxWarning,
msg="Signed values in If/Elif conditions usually result from inverting Python "
"booleans with ~, which leads to unexpected results: ~True is -2, which is "
"truthful. Replace `~flag` with `not flag`. (If this is a false positive, "
"silence this warning with `m.If(x)` → `m.If(x.bool())`.)"):
"booleans with ~, which leads to unexpected results. Replace `~flag` with "
"`not flag`. (If this is a false positive, silence this warning with "
"`m.If(x)` → `m.If(x.bool())`.)"):
with m.Elif(~True):
pass