-from nmigen import Module, Signal
-from nmigen.cli import main
+# SPDX-License-Identifier: LGPL-2.1-or-later
+# See Notices.txt for copyright information
+from nmigen import Signal, Module, Const, Cat
+from nmigen.cli import verilog, rtlil
-size = 11
-class LFSR:
- def __init__(self):
+class LFSRPolynomial(set):
+ """ implements a polynomial for use in LFSR
+ """
+ def __init__(self, exponents=()):
+ for e in exponents:
+ assert isinstance(e, int), TypeError("%s must be an int" % repr(e))
+ assert (e >= 0), ValueError("%d must not be negative" % e)
+ set.__init__(self, set(exponents).union({0})) # must contain zero
- # Output
- self.enable = Signal(1)
- self.o = Signal(size)
+ @property
+ def max_exponent(self):
+ return max(self) # derived from set, so this returns the max exponent
- def elaborate(self, platform=None):
+ @property
+ def exponents(self):
+ exponents = list(self) # get elements of set as a list
+ exponents.sort(reverse=True)
+ return exponents
+
+ def __str__(self):
+ expd = {0: "1", 1: 'x', 2: "x^{}"} # case 2 isn't 2, it's min(i,2)
+ retval = map(lambda i: expd[min(i,2)].format(i), self.exponents)
+ return " + ".join(retval)
+
+ def __repr__(self):
+ return "LFSRPolynomial(%s)" % self.exponents
+
+
+# list of selected polynomials from https://web.archive.org/web/20190418121923/https://en.wikipedia.org/wiki/Linear-feedback_shift_register#Some_polynomials_for_maximal_LFSRs # noqa
+LFSR_POLY_2 = LFSRPolynomial([2, 1, 0])
+LFSR_POLY_3 = LFSRPolynomial([3, 2, 0])
+LFSR_POLY_4 = LFSRPolynomial([4, 3, 0])
+LFSR_POLY_5 = LFSRPolynomial([5, 3, 0])
+LFSR_POLY_6 = LFSRPolynomial([6, 5, 0])
+LFSR_POLY_7 = LFSRPolynomial([7, 6, 0])
+LFSR_POLY_8 = LFSRPolynomial([8, 6, 5, 4, 0])
+LFSR_POLY_9 = LFSRPolynomial([9, 5, 0])
+LFSR_POLY_10 = LFSRPolynomial([10, 7, 0])
+LFSR_POLY_11 = LFSRPolynomial([11, 9, 0])
+LFSR_POLY_12 = LFSRPolynomial([12, 11, 10, 4, 0])
+LFSR_POLY_13 = LFSRPolynomial([13, 12, 11, 8, 0])
+LFSR_POLY_14 = LFSRPolynomial([14, 13, 12, 2, 0])
+LFSR_POLY_15 = LFSRPolynomial([15, 14, 0])
+LFSR_POLY_16 = LFSRPolynomial([16, 15, 13, 4, 0])
+LFSR_POLY_17 = LFSRPolynomial([17, 14, 0])
+LFSR_POLY_18 = LFSRPolynomial([18, 11, 0])
+LFSR_POLY_19 = LFSRPolynomial([19, 18, 17, 14, 0])
+LFSR_POLY_20 = LFSRPolynomial([20, 17, 0])
+LFSR_POLY_21 = LFSRPolynomial([21, 19, 0])
+LFSR_POLY_22 = LFSRPolynomial([22, 21, 0])
+LFSR_POLY_23 = LFSRPolynomial([23, 18, 0])
+LFSR_POLY_24 = LFSRPolynomial([24, 23, 22, 17, 0])
+
+
+class LFSR(LFSRPolynomial):
+ """ implements a Linear Feedback Shift Register
+ """
+ def __init__(self, polynomial):
+ """ Inputs:
+ ------
+ :polynomial: the polynomial to feedback on. may be a LFSRPolynomial
+ instance or an iterable of ints (list/tuple/generator)
+ :enable: enable (set LO to disable. NOTE: defaults to HI)
+
+ Outputs:
+ -------
+ :state: the LFSR state. length is taken from the polynomial
+
+ Note: if an LFSRPolynomial is passed in as the input, because
+ LFSRPolynomial is derived from set() it's ok:
+ LFSRPolynomial(LFSRPolynomial(p)) == LFSRPolynomial(p)
+ """
+ LFSRPolynomial.__init__(self, polynomial)
+ self.state = Signal(self.max_exponent, reset=1)
+ self.enable = Signal(reset=1)
+
+ def elaborate(self, platform):
m = Module()
+ # do absolutely nothing if the polynomial is empty (always has a zero)
+ if self.max_exponent <= 1:
+ return m
+
+ # create XOR-bunch, select bits from state based on exponent
+ feedback = Const(0) # doesn't do any harm starting from 0b0 (xor chain)
+ for exponent in self:
+ if exponent > 0: # don't have to skip, saves CPU cycles though
+ feedback ^= self.state[exponent - 1]
+
+ # if enabled, shift-and-feedback
+ with m.If(self.enable):
+ # shift up lower bits by Cat'ing in a new bit zero (feedback)
+ newstate = Cat(feedback, self.state[0:self.max_exponent - 1])
+ m.d.sync += self.state.eq(newstate)
- for i in range(size):
- with m.If(self.enable):
- if i == 0:
- zero = self.o[0]
- one = self.o[1]
- m.d.sync += self.o[0].eq(zero ^ one)
- if i == 3:
- zero = self.o[0]
- three = self.o[4]
- m.d.sync += self.o[3].eq(zero ^ three)
- else:
- prev = self.o[(i + 1) % size]
- m.d.sync += self.o[i].eq(prev)
return m
+
+# example: Poly24
+if __name__ == '__main__':
+ p24 = rtlil.convert(LFSR(LFSR_POLY_24))
+ with open("lfsr2_p24.il", "w") as f:
+ f.write(p24)
--- /dev/null
+# SPDX-License-Identifier: LGPL-2.1-or-later
+# See Notices.txt for copyright information
+from nmigen import Module
+from typing import Iterable, Optional, Iterator, Any, Union
+from typing_extensions import final
+
+
+@final
+class LFSRPolynomial(set):
+ def __init__(self, exponents: Iterable[int] = ()):
+ def elements() -> Iterable[int]: ...
+ @property
+ def exponents(self) -> list[int]: ...
+ def __str__(self) -> str: ...
+ def __repr__(self) -> str: ...
+
+
+@final
+class LFSR:
+ def __init__(self, polynomial: Union[Iterable[int], LFSRPolynomial]): ...
+ @property
+ def width(self) -> int: ...
+ def elaborate(self, platform: Any) -> Module: ...
+++ /dev/null
-# SPDX-License-Identifier: LGPL-2.1-or-later
-# See Notices.txt for copyright information
-from nmigen import Signal, Module, Const, Cat
-from nmigen.cli import verilog, rtlil
-
-
-class LFSRPolynomial(set):
- """ implements a polynomial for use in LFSR
- """
- def __init__(self, exponents=()):
- for e in exponents:
- assert isinstance(e, int), TypeError("%s must be an int" % repr(e))
- assert (e >= 0), ValueError("%d must not be negative" % e)
- set.__init__(self, set(exponents).union({0})) # must contain zero
-
- @property
- def max_exponent(self):
- return max(self) # derived from set, so this returns the max exponent
-
- @property
- def exponents(self):
- exponents = list(self) # get elements of set as a list
- exponents.sort(reverse=True)
- return exponents
-
- def __str__(self):
- expd = {0: "1", 1: 'x', 2: "x^{}"} # case 2 isn't 2, it's min(i,2)
- retval = map(lambda i: expd[min(i,2)].format(i), self.exponents)
- return " + ".join(retval)
-
- def __repr__(self):
- return "LFSRPolynomial(%s)" % self.exponents
-
-
-# list of selected polynomials from https://web.archive.org/web/20190418121923/https://en.wikipedia.org/wiki/Linear-feedback_shift_register#Some_polynomials_for_maximal_LFSRs # noqa
-LFSR_POLY_2 = LFSRPolynomial([2, 1, 0])
-LFSR_POLY_3 = LFSRPolynomial([3, 2, 0])
-LFSR_POLY_4 = LFSRPolynomial([4, 3, 0])
-LFSR_POLY_5 = LFSRPolynomial([5, 3, 0])
-LFSR_POLY_6 = LFSRPolynomial([6, 5, 0])
-LFSR_POLY_7 = LFSRPolynomial([7, 6, 0])
-LFSR_POLY_8 = LFSRPolynomial([8, 6, 5, 4, 0])
-LFSR_POLY_9 = LFSRPolynomial([9, 5, 0])
-LFSR_POLY_10 = LFSRPolynomial([10, 7, 0])
-LFSR_POLY_11 = LFSRPolynomial([11, 9, 0])
-LFSR_POLY_12 = LFSRPolynomial([12, 11, 10, 4, 0])
-LFSR_POLY_13 = LFSRPolynomial([13, 12, 11, 8, 0])
-LFSR_POLY_14 = LFSRPolynomial([14, 13, 12, 2, 0])
-LFSR_POLY_15 = LFSRPolynomial([15, 14, 0])
-LFSR_POLY_16 = LFSRPolynomial([16, 15, 13, 4, 0])
-LFSR_POLY_17 = LFSRPolynomial([17, 14, 0])
-LFSR_POLY_18 = LFSRPolynomial([18, 11, 0])
-LFSR_POLY_19 = LFSRPolynomial([19, 18, 17, 14, 0])
-LFSR_POLY_20 = LFSRPolynomial([20, 17, 0])
-LFSR_POLY_21 = LFSRPolynomial([21, 19, 0])
-LFSR_POLY_22 = LFSRPolynomial([22, 21, 0])
-LFSR_POLY_23 = LFSRPolynomial([23, 18, 0])
-LFSR_POLY_24 = LFSRPolynomial([24, 23, 22, 17, 0])
-
-
-class LFSR(LFSRPolynomial):
- """ implements a Linear Feedback Shift Register
- """
- def __init__(self, polynomial):
- """ Inputs:
- ------
- :polynomial: the polynomial to feedback on. may be a LFSRPolynomial
- instance or an iterable of ints (list/tuple/generator)
- :enable: enable (set LO to disable. NOTE: defaults to HI)
-
- Outputs:
- -------
- :state: the LFSR state. length is taken from the polynomial
-
- Note: if an LFSRPolynomial is passed in as the input, because
- LFSRPolynomial is derived from set() it's ok:
- LFSRPolynomial(LFSRPolynomial(p)) == LFSRPolynomial(p)
- """
- LFSRPolynomial.__init__(self, polynomial)
- self.state = Signal(self.max_exponent, reset=1)
- self.enable = Signal(reset=1)
-
- def elaborate(self, platform):
- m = Module()
- # do absolutely nothing if the polynomial is empty (always has a zero)
- if self.max_exponent <= 1:
- return m
-
- # create XOR-bunch, select bits from state based on exponent
- feedback = Const(0) # doesn't do any harm starting from 0b0 (xor chain)
- for exponent in self:
- if exponent > 0: # don't have to skip, saves CPU cycles though
- feedback ^= self.state[exponent - 1]
-
- # if enabled, shift-and-feedback
- with m.If(self.enable):
- # shift up lower bits by Cat'ing in a new bit zero (feedback)
- newstate = Cat(feedback, self.state[0:self.max_exponent - 1])
- m.d.sync += self.state.eq(newstate)
-
- return m
-
-
-# example: Poly24
-if __name__ == '__main__':
- p24 = rtlil.convert(LFSR(LFSR_POLY_24))
- with open("lfsr2_p24.il", "w") as f:
- f.write(p24)
+++ /dev/null
-# SPDX-License-Identifier: LGPL-2.1-or-later
-# See Notices.txt for copyright information
-from nmigen import Module
-from typing import Iterable, Optional, Iterator, Any, Union
-from typing_extensions import final
-
-
-@final
-class LFSRPolynomial(set):
- def __init__(self, exponents: Iterable[int] = ()):
- def elements() -> Iterable[int]: ...
- @property
- def exponents(self) -> list[int]: ...
- def __str__(self) -> str: ...
- def __repr__(self) -> str: ...
-
-
-@final
-class LFSR:
- def __init__(self, polynomial: Union[Iterable[int], LFSRPolynomial]): ...
- @property
- def width(self) -> int: ...
- def elaborate(self, platform: Any) -> Module: ...
projects / soc.git / commitdiff