Re: [myhdl-list] intbv.wrap()

[Christopher F. <chr...@gm...>]

The following are the proposed changes to the intbv class (WIP).

I added the attribute but I have not added the "wrap" __setitem__ and i* 
operators.

Need to determine if the intbv.wrap function will remain a public 
function or move to a private function.  If it remains an advertised 
public function then the conversion will need to handle the wrap function.

Feedback always welcome.

Note the attached change set is *INCOMPLETE* add for convenience.

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# Simple test code
x = intbv(0, min=-8, max=8)
for ii in xrange(x):
     x[:] = x.wrap(x+1)
     print x

for ii in range(1333):
     x[:] = x.wrap(x+77)
     # bound checking will catch errors, more test cases needed
	
# Additions to the intbv class
class intbv(object):
     __slots__ = ('_val', '_min', '_max', '_nrbits', '_range', '_wrap')

     def __init__(self, val=0, min=None, max=None, wrap=False, _nrbits=0):

         ...

         self._nrbits = _nrbits
         self._wrap  = wrap
         self._range = 2**_nrbits


     def wrap(self, val):
         """ Wrap the value back to the range of the inbv

         The following will check that the defined min-max is the full
         range of the binary word.  If the full range is specified if
         the value is outside the bounds of the range it will be adjusted
         to the proper value in bounds.
         """
         assert abs(self.min) == self.max
         assert (abs(self.min) + self.max) == self._range

         rval = self.min + ((val +self.max) % self._range)

         return rval
----------------------