Indexing an Array of differently shaped integer constants with a Signal generates invalid RTLIL #15

the6p4c · 2018-12-31T02:12:27Z

The following MWE generates invalid RTLIL and as such fails Verilog generation.

from nmigen import *
from nmigen.cli import main

class Test:
    def __init__(self):
        self.out = Signal(8)

    def get_fragment(self, platform):
        data = [0b100, 0b1000, 0b10000]
        arr = Array(data)
        idx = Signal(max=len(data))

        m = Module()
        m.d.comb += self.out.eq(arr[idx])
        m.d.sync += idx.eq(idx + 1)
        return m.lower(platform)

test = Test()
main(test, ports=[test.out])

The following error is produced:

D:\test> python test.py generate -t v test.v
Traceback (most recent call last):
  File "test.py", line 19, in <module>
    main(test, ports=[test.out])
  File "D:\Program Files\Python36\lib\site-packages\nmigen-0.1-py3.6.egg\nmigen\cli.py", line 74, in main
    main_runner(parser, parser.parse_args(), *args, **kwargs)
  File "D:\Program Files\Python36\lib\site-packages\nmigen-0.1-py3.6.egg\nmigen\cli.py", line 56, in main_runner
    output = verilog.convert(fragment, name=name, ports=ports)
  File "D:\Program Files\Python36\lib\site-packages\nmigen-0.1-py3.6.egg\nmigen\back\verilog.py", line 37, in convert
    raise YosysError(error.strip())
nmigen.back.verilog.YosysError: ERROR: Found error in internal cell \top.$5 ($pos) at kernel/rtlil.cc:704:
  attribute \src "test.py:14"
  cell $pos $5
    parameter \Y_WIDTH 8
    parameter \A_WIDTH 5
    parameter \A_SIGNED 0
    connect \Y $4
    connect \A 4'1000
  end

This error does not occur when the elements of the Array all have the same shape (i.e. [0b100, 0b101, 0b111, 0b110]).

The text was updated successfully, but these errors were encountered:

whitequark closed this as completed in ae3c583 Dec 31, 2018

whitequark added the bug label Jun 28, 2019

whitequark added this to the 0.1 milestone Jun 28, 2019

mithro mentioned this issue Jul 9, 2019

Support silkscreen references (and other information) in platform definitions #143

Open

nmigen-issue-migration mentioned this issue Jan 27, 2020

Indexing an Array of differently shaped integer constants with a Signal generates invalid RTLIL amaranth-lang/amaranth#17

Closed

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Indexing an Array of differently shaped integer constants with a Signal generates invalid RTLIL #15

Indexing an Array of differently shaped integer constants with a Signal generates invalid RTLIL #15

the6p4c commented Dec 31, 2018 •

edited

Indexing an Array of differently shaped integer constants with a Signal generates invalid RTLIL #15

Indexing an Array of differently shaped integer constants with a Signal generates invalid RTLIL #15

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the6p4c commented Dec 31, 2018 • edited

the6p4c commented Dec 31, 2018 •

edited