Packed structure initialization/assignment


Subject: Packed structure initialization/assignment
From: Gordon Vreugdenhil (gvreugde@synopsys.com)
Date: Mon Oct 14 2002 - 08:38:37 PDT


Given some packed structure type and a variable declaration of the
form:

   Packed_struct_type packed_var = {1,2,3,4,5,6,7,8,9};

it is not clear whether the {...} expression should be interpreted
as a concat or a structure.

My thoughts on the options:
  1) "prefer" to treat this as a structure but allow that only if
     the self-determined properties of each element match the
     fields.
  2) always require this to be a concat unless coerced.
  3) always require this to be a concat.

The problem is that the interpretation of {...} must now appeal
to the LHS of the assignment or initialization. I don't particularly
like that but don't see any way to avoid it. Even in the
coercion case, one must figure out that
   Packed_struct_type'{....}
is supposed to be a structural creation field-by-field versus a
concat followed by coercion of the bitvector to the packed field type.

Gord.

-- 
----------------------------------------------------------------------
Gord Vreugdenhil                                 gvreugde@synopsys.com
Staff Engineer, VCS (Verification Tech. Group)   (503) 547-6054
Synopsys Inc., Beaverton OR



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