From: whitequark Date: Sat, 3 Aug 2019 13:05:41 +0000 (+0000) Subject: hdl.ast: deprecate Value.part, add Value.{bit,word}_select. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d3ae98673595cc29e86de7a97ac469334c5d18d0;p=nmigen.git hdl.ast: deprecate Value.part, add Value.{bit,word}_select. Fixes #148. --- diff --git a/nmigen/back/pysim.py b/nmigen/back/pysim.py index 76ef2d6..e88972c 100644 --- a/nmigen/back/pysim.py +++ b/nmigen/back/pysim.py @@ -177,11 +177,12 @@ class _RHSValueCompiler(_ValueCompiler): return lambda state: normalize((arg(state) >> shift) & mask, shape) def on_Part(self, value): - 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) + shape = value.shape() + arg = self(value.value) + shift = self(value.offset) + mask = (1 << value.width) - 1 + stride = value.stride + return lambda state: normalize((arg(state) >> shift(state) * stride) & mask, shape) def on_Cat(self, value): shape = value.shape() @@ -260,13 +261,14 @@ class _LHSValueCompiler(_ValueCompiler): return eval def on_Part(self, value): - lhs_r = self.rhs_compiler(value.value) - lhs_l = self(value.value) - shift = self.rhs_compiler(value.offset) - mask = (1 << value.width) - 1 + lhs_r = self.rhs_compiler(value.value) + lhs_l = self(value.value) + shift = self.rhs_compiler(value.offset) + mask = (1 << value.width) - 1 + stride = value.stride def eval(state, rhs): lhs_value = lhs_r(state) - shift_value = shift(state) + shift_value = shift(state) * stride lhs_value &= ~(mask << shift_value) lhs_value |= (rhs & mask) << shift_value lhs_l(state, lhs_value) diff --git a/nmigen/back/rtlil.py b/nmigen/back/rtlil.py index 55d15d9..5d23156 100644 --- a/nmigen/back/rtlil.py +++ b/nmigen/back/rtlil.py @@ -532,6 +532,8 @@ class _RHSValueCompiler(_ValueCompiler): def on_Part(self, value): lhs, rhs = value.value, value.offset + if value.stride != 1: + rhs *= value.stride lhs_bits, lhs_sign = lhs.shape() rhs_bits, rhs_sign = rhs.shape() res_bits, res_sign = value.shape() diff --git a/nmigen/hdl/ast.py b/nmigen/hdl/ast.py index b1d1a7e..68c3f10 100644 --- a/nmigen/hdl/ast.py +++ b/nmigen/hdl/ast.py @@ -146,15 +146,21 @@ class Value(metaclass=ABCMeta): """ return ~premise | conclusion + # TODO(nmigen-0.2): move this to nmigen.compat and make it a deprecated extension + @deprecated("instead of `.part`, use `.bit_slip`") def part(self, offset, width): - """Indexed part-select. + return Part(self, offset, width, src_loc_at=1) + + def bit_select(self, offset, width): + """Part-select with bit granularity. - Selects a constant width but variable offset part of a ``Value``. + Selects a constant width but variable offset part of a ``Value``, such that successive + parts overlap by all but 1 bit. Parameters ---------- offset : Value, in - start point of the selected bits + index of first selected bit width : int number of selected bits @@ -163,7 +169,27 @@ class Value(metaclass=ABCMeta): Part, out Selected part of the ``Value`` """ - return Part(self, offset, width, src_loc_at=1) + return Part(self, offset, width, stride=1, src_loc_at=1) + + def word_select(self, offset, width): + """Part-select with word granularity. + + Selects a constant width but variable offset part of a ``Value``, such that successive + parts do not overlap. + + Parameters + ---------- + offset : Value, in + index of first selected word + width : int + number of selected bits + + Returns + ------- + Part, out + Selected part of the ``Value`` + """ + return Part(self, offset, width, stride=width, src_loc_at=1) def eq(self, value): """Assignment. @@ -434,14 +460,17 @@ class Slice(Value): @final class Part(Value): - def __init__(self, value, offset, width, *, src_loc_at=0): + def __init__(self, value, offset, width, stride=1, *, src_loc_at=0): if not isinstance(width, int) or width < 0: raise TypeError("Part width must be a non-negative integer, not '{!r}'".format(width)) + if not isinstance(stride, int) or stride <= 0: + raise TypeError("Part stride must be a positive integer, not '{!r}'".format(stride)) super().__init__(src_loc_at=src_loc_at) self.value = value self.offset = Value.wrap(offset) self.width = width + self.stride = stride def shape(self): return self.width, False @@ -453,7 +482,8 @@ class Part(Value): return self.value._rhs_signals() | self.offset._rhs_signals() def __repr__(self): - return "(part {} {} {})".format(repr(self.value), repr(self.offset), self.width) + return "(part {} {} {} {})".format(repr(self.value), repr(self.offset), + self.width, self.stride) @final @@ -1240,7 +1270,7 @@ class ValueKey: return hash((ValueKey(self.value.value), self.value.start, self.value.end)) elif isinstance(self.value, Part): return hash((ValueKey(self.value.value), ValueKey(self.value.offset), - self.value.width)) + self.value.width, self.value.stride)) elif isinstance(self.value, Cat): return hash(tuple(ValueKey(o) for o in self.value.parts)) elif isinstance(self.value, ArrayProxy): @@ -1276,7 +1306,8 @@ class ValueKey: elif isinstance(self.value, Part): return (ValueKey(self.value.value) == ValueKey(other.value.value) and ValueKey(self.value.offset) == ValueKey(other.value.offset) and - self.value.width == other.value.width) + self.value.width == other.value.width and + self.value.stride == other.value.stride) elif isinstance(self.value, Cat): return all(ValueKey(a) == ValueKey(b) for a, b in zip(self.value.parts, other.value.parts)) diff --git a/nmigen/hdl/xfrm.py b/nmigen/hdl/xfrm.py index db3260e..25f2825 100644 --- a/nmigen/hdl/xfrm.py +++ b/nmigen/hdl/xfrm.py @@ -157,7 +157,8 @@ class ValueTransformer(ValueVisitor): return Slice(self.on_value(value.value), value.start, value.end) def on_Part(self, value): - return Part(self.on_value(value.value), self.on_value(value.offset), value.width) + return Part(self.on_value(value.value), self.on_value(value.offset), + value.width, value.stride) def on_Cat(self, value): return Cat(self.on_value(o) for o in value.parts) diff --git a/nmigen/test/test_hdl_ast.py b/nmigen/test/test_hdl_ast.py index 54824b1..6fa0a1c 100644 --- a/nmigen/test/test_hdl_ast.py +++ b/nmigen/test/test_hdl_ast.py @@ -294,24 +294,52 @@ class SliceTestCase(FHDLTestCase): self.assertEqual(repr(s1), "(slice (const 4'd10) 2:3)") -class PartTestCase(FHDLTestCase): +class BitSelectTestCase(FHDLTestCase): def setUp(self): self.c = Const(0, 8) self.s = Signal(max=self.c.nbits) def test_shape(self): - s1 = self.c.part(self.s, 2) + s1 = self.c.bit_select(self.s, 2) self.assertEqual(s1.shape(), (2, False)) - s2 = self.c.part(self.s, 0) + s2 = self.c.bit_select(self.s, 0) self.assertEqual(s2.shape(), (0, False)) + def test_stride(self): + s1 = self.c.bit_select(self.s, 2) + self.assertEqual(s1.stride, 1) + + def test_width_bad(self): + with self.assertRaises(TypeError): + self.c.bit_select(self.s, -1) + + def test_repr(self): + s = self.c.bit_select(self.s, 2) + self.assertEqual(repr(s), "(part (const 8'd0) (sig s) 2 1)") + + +class WordSelectTestCase(FHDLTestCase): + def setUp(self): + self.c = Const(0, 8) + self.s = Signal(max=self.c.nbits) + + def test_shape(self): + s1 = self.c.word_select(self.s, 2) + self.assertEqual(s1.shape(), (2, False)) + + def test_stride(self): + s1 = self.c.word_select(self.s, 2) + self.assertEqual(s1.stride, 2) + def test_width_bad(self): with self.assertRaises(TypeError): - self.c.part(self.s, -1) + self.c.word_select(self.s, 0) + with self.assertRaises(TypeError): + self.c.word_select(self.s, -1) def test_repr(self): - s = self.c.part(self.s, 2) - self.assertEqual(repr(s), "(part (const 8'd0) (sig s) 2)") + s = self.c.word_select(self.s, 2) + self.assertEqual(repr(s), "(part (const 8'd0) (sig s) 2 2)") class CatTestCase(FHDLTestCase): diff --git a/nmigen/test/test_sim.py b/nmigen/test/test_sim.py index c57056b..2a3d93d 100644 --- a/nmigen/test/test_sim.py +++ b/nmigen/test/test_sim.py @@ -151,18 +151,30 @@ class SimulatorUnitTestCase(FHDLTestCase): stmt2 = lambda y, a: y[2:4].eq(a) self.assertStatement(stmt2, [C(0b01, 2)], C(0b11110111, 8), reset=0b11111011) - def test_part(self): - stmt = lambda y, a, b: y.eq(a.part(b, 3)) + def test_bit_select(self): + stmt = lambda y, a, b: y.eq(a.bit_select(b, 3)) self.assertStatement(stmt, [C(0b10110100, 8), C(0)], C(0b100, 3)) self.assertStatement(stmt, [C(0b10110100, 8), C(2)], C(0b101, 3)) self.assertStatement(stmt, [C(0b10110100, 8), C(3)], C(0b110, 3)) - def test_part_lhs(self): - stmt = lambda y, a, b: y.part(a, 3).eq(b) + def test_bit_select_lhs(self): + stmt = lambda y, a, b: y.bit_select(a, 3).eq(b) self.assertStatement(stmt, [C(0), C(0b100, 3)], C(0b11111100, 8), reset=0b11111111) self.assertStatement(stmt, [C(2), C(0b101, 3)], C(0b11110111, 8), reset=0b11111111) self.assertStatement(stmt, [C(3), C(0b110, 3)], C(0b11110111, 8), reset=0b11111111) + def test_word_select(self): + stmt = lambda y, a, b: y.eq(a.word_select(b, 3)) + self.assertStatement(stmt, [C(0b10110100, 8), C(0)], C(0b100, 3)) + self.assertStatement(stmt, [C(0b10110100, 8), C(1)], C(0b110, 3)) + self.assertStatement(stmt, [C(0b10110100, 8), C(2)], C(0b010, 3)) + + def test_word_select_lhs(self): + stmt = lambda y, a, b: y.word_select(a, 3).eq(b) + self.assertStatement(stmt, [C(0), C(0b100, 3)], C(0b11111100, 8), reset=0b11111111) + self.assertStatement(stmt, [C(1), C(0b101, 3)], C(0b11101111, 8), reset=0b11111111) + self.assertStatement(stmt, [C(2), C(0b110, 3)], C(0b10111111, 8), reset=0b11111111) + def test_cat(self): stmt = lambda y, *xs: y.eq(Cat(*xs)) self.assertStatement(stmt, [C(0b10, 2), C(0b01, 2)], C(0b0110, 4))