[myhdl-list] Slicing an unsigned intbv to a signed one

[Günter D. <dan...@we...>]

Hi,

I try to figure out whether there is a simple way to slice bits from an 
unsigned intbv and assign them to a signed intbv and have the msb of the 
slice specify the sign of the signed intbv? In addition to that it 
should be convertible with toVerilog/VHDL.

For example, what I try to do is split up a 8 bit wide data word that is 
considered unsigned, that means min=0 and max=256, into two 4 bit wide 
data words with those being considered signed, meaning min=-8 max = 8.

In Verilog that can be done using the $signed() system task. Is there a 
simple way to do that with myhdl?

The problem I am running into is when the msb in the slice is set, that 
when assigning it to a signed intbv it is complaining that the value 
exceeds the max allowed value as the slice is considered a positive value.

Thanks for the help.

Cheers,

Guenter