raise ValueError("partition_points doesn't fit in output_width")
self._reg_partition_points = self.partition_points.like()
- max_level = AddReduce.get_max_level(len(self.inputs))
+ max_level = AddReduceSingle.get_max_level(len(self.inputs))
for level in self.register_levels:
if level > max_level:
raise ValueError(
"not enough adder levels for specified register levels")
+ self.groups = AddReduceSingle.full_adder_groups(len(self.inputs))
+ self._intermediate_terms = []
+ if len(self.groups) != 0:
+ self.create_next_terms()
+
@staticmethod
def get_max_level(input_count):
"""Get the maximum level.
"""
retval = 0
while True:
- groups = AddReduce.full_adder_groups(input_count)
+ groups = AddReduceSingle.full_adder_groups(input_count)
if len(groups) == 0:
return retval
input_count %= FULL_ADDER_INPUT_COUNT
input_count += 2 * len(groups)
retval += 1
+
@staticmethod
def full_adder_groups(input_count):
"""Get ``inputs`` indices for which a full adder should be built."""
input_count - FULL_ADDER_INPUT_COUNT + 1,
FULL_ADDER_INPUT_COUNT)
- def _elaborate(self, platform):
+ def elaborate(self, platform):
"""Elaborate this module."""
m = Module()
m.d.comb += resized_input_assignments
m.d.comb += self._reg_partition_points.eq(self.partition_points)
- groups = AddReduceSingle.full_adder_groups(len(self.inputs))
+ for (value, term) in self._intermediate_terms:
+ m.d.comb += term.eq(value)
+
# if there are no full adders to create, then we handle the base cases
# and return, otherwise we go on to the recursive case
- if len(groups) == 0:
+ if len(self.groups) == 0:
if len(self.inputs) == 0:
# use 0 as the default output value
m.d.comb += self.output.eq(0)
# handle single input
m.d.comb += self.output.eq(self._resized_inputs[0])
else:
- # base case for adding 2 or more inputs, which get recursively
- # reduced to 2 inputs
+ # base case for adding 2 inputs
assert len(self.inputs) == 2
adder = PartitionedAdder(len(self.output),
self._reg_partition_points)
m.d.comb += adder.a.eq(self._resized_inputs[0])
m.d.comb += adder.b.eq(self._resized_inputs[1])
m.d.comb += self.output.eq(adder.output)
- return None, m
+ return m
+
+ mask = self._reg_partition_points.as_mask(len(self.output))
+ m.d.comb += self.part_mask.eq(mask)
+
+ # add and link the intermediate term modules
+ for i, (iidx, adder_i) in enumerate(self.adders):
+ setattr(m.submodules, f"adder_{i}", adder_i)
+
+ m.d.comb += adder_i.in0.eq(self._resized_inputs[iidx])
+ m.d.comb += adder_i.in1.eq(self._resized_inputs[iidx + 1])
+ m.d.comb += adder_i.in2.eq(self._resized_inputs[iidx + 2])
+ m.d.comb += adder_i.mask.eq(self.part_mask)
+
+ return m
+
+ def create_next_terms(self):
# go on to prepare recursive case
intermediate_terms = []
+ _intermediate_terms = []
def add_intermediate_term(value):
intermediate_term = Signal(
len(self.output),
name=f"intermediate_terms[{len(intermediate_terms)}]")
+ _intermediate_terms.append((value, intermediate_term))
intermediate_terms.append(intermediate_term)
- m.d.comb += intermediate_term.eq(value)
# store mask in intermediary (simplifies graph)
- part_mask = Signal(len(self.output), reset_less=True)
- mask = self._reg_partition_points.as_mask(len(self.output))
- m.d.comb += part_mask.eq(mask)
+ self.part_mask = Signal(len(self.output), reset_less=True)
# create full adders for this recursive level.
# this shrinks N terms to 2 * (N // 3) plus the remainder
- for i in groups:
+ self.adders = []
+ for i in self.groups:
adder_i = MaskedFullAdder(len(self.output))
- setattr(m.submodules, f"adder_{i}", adder_i)
- m.d.comb += adder_i.in0.eq(self._resized_inputs[i])
- m.d.comb += adder_i.in1.eq(self._resized_inputs[i + 1])
- m.d.comb += adder_i.in2.eq(self._resized_inputs[i + 2])
- m.d.comb += adder_i.mask.eq(part_mask)
+ self.adders.append((i, adder_i))
# add both the sum and the masked-carry to the next level.
# 3 inputs have now been reduced to 2...
add_intermediate_term(adder_i.sum)
else:
assert len(self.inputs) % FULL_ADDER_INPUT_COUNT == 0
- return intermediate_terms, m
+ self.intermediate_terms = intermediate_terms
+ self._intermediate_terms = _intermediate_terms
-class AddReduce(AddReduceSingle):
+class AddReduce(Elaboratable):
"""Recursively Add list of numbers together.
:attribute inputs: input ``Signal``s to be summed. Modification not
pipeline registers.
:param partition_points: the input partition points.
"""
- AddReduceSingle.__init__(self, inputs, output_width, register_levels,
- partition_points)
+ self.inputs = inputs
+ self.output = Signal(output_width)
+ self.output_width = output_width
+ self.register_levels = register_levels
+ self.partition_points = partition_points
- def next_register_levels(self):
+ self.create_levels()
+
+ @staticmethod
+ def next_register_levels(register_levels):
"""``Iterable`` of ``register_levels`` for next recursive level."""
- for level in self.register_levels:
+ for level in register_levels:
if level > 0:
yield level - 1
+ def create_levels(self):
+ """creates reduction levels"""
+
+ mods = []
+ next_levels = self.register_levels
+ partition_points = self.partition_points
+ inputs = self.inputs
+ while True:
+ next_level = AddReduceSingle(inputs, self.output_width, next_levels,
+ partition_points)
+ mods.append(next_level)
+ if len(next_level.groups) == 0:
+ break
+ next_levels = list(AddReduce.next_register_levels(next_levels))
+ partition_points = next_level._reg_partition_points
+ inputs = next_level.intermediate_terms
+
+ self.levels = mods
+
def elaborate(self, platform):
"""Elaborate this module."""
- intermediate_terms, m = AddReduceSingle._elaborate(self, platform)
- if intermediate_terms is None:
- return m
+ m = Module()
+
+ for i, next_level in enumerate(self.levels):
+ setattr(m.submodules, "next_level%d" % i, next_level)
- # recursive invocation of ``AddReduce``
- next_level = AddReduce(intermediate_terms,
- len(self.output),
- self.next_register_levels(),
- self._reg_partition_points)
- m.submodules.next_level = next_level
+ # output comes from last module
m.d.comb += self.output.eq(next_level.output)
+
return m
projects / ieee754fpu.git / commitdiff