Re: [myhdl-list] myhdl.concat

[Jan D. <ja...@ja...>]

Correct, thanks for the bug report, and for entering it in BitBucket.
This is solved in development.

On 08/09/2014 10:17 AM, Thomas Heller wrote:
> I expected myhdl.concat to return a bit-wise concatenation of the arguments.
> However, when I use concat(unsigned, signed) this is not the case.
> The following program prints '7FFFFFFD' instead of '8FFFFFFD':
>
> <code>
> #!/usr/bin/python2.7-32
> # -*- coding: utf-8 -*-
>
> import myhdl
>
> def unsigned(width, value=0, cls=myhdl.intbv):
>       """Create an unsigned signal based on a bitvector with the
>       specified width and initial value.
>       """
>       return myhdl.Signal(cls(value, 0, 2**width))
>
> def signed(width, value=0, cls=myhdl.intbv):
>       """Create an signed signal based on a bitvector with the
>       specified width and initial value.
>       """
>       return myhdl.Signal(cls(value, -2**(width-1), 2**(width-1)))
>
> a = unsigned(4, 8)
> b = signed(28, -3)
>
> print "%08X" % myhdl.concat(a, b)
> </code>
>
> Is this correct?  Changing (in myhdl 0.8, module _concat.py) this line
> gives the result that I expected:
>
> --- _concat.py~ Mon Aug  4 12:20:26 2014
> +++ _concat.py  Sat Aug  9 10:15:05 2014
> @@ -65,7 +65,7 @@
>            if not w:
>                raise TypeError, "concat: arg on pos %d should have
> length" % (i+1)
>            width += w
> -        val = val*(2**w) + v
> +        val = val*(2**w) | (v % 2**len(v))
>
>        if basewidth:
>            return intbv(val, _nrbits=basewidth + width)
>
>
> Thomas
>
>
> ------------------------------------------------------------------------------
>


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