RE: [vhdl-200x] Corrections to Minutes for VHDL-200X-FT meeting, San Jose Dec 4, 2003

Subject: RE: [vhdl-200x] Corrections to Minutes for VHDL-200X-FT meeting, San Jose Dec 4, 2003
From: Bailey, Stephen (SBailey@model.com)
Date: Tue Dec 16 2003 - 15:35:30 PST

Hamish,

> I think this example demonstrates a good point: what test would COND
> operator use on std_logic? Probably test for '1'. Thus the
> above is not
> equivalent in the presence of metavalues;
>
> if not we_n then
>
> is not the same as
>
> if we_n = '0' then
>
> but really is
>
> if we_n /= '1' then

This is incorrect. Remember that with the implicit COND call:

  if not we_n then

is the same as

  if COND( not we_n ) then

Currently, std_logic_1164.not will return '1' whenever we_n is '0' or 'L', it does not return '1' for any other value. Therefore, it is equivalent to:

  if (we_n = '0') or (we_n = 'L') then

Which should be considered satisfactory, correct and what is expected.

-Steve Bailey

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