This patch adds the constant system functions for Verilog-2005
and Verilog-AMS. These are evaluated at compile time. $abs(),
$min() and $max() support their polymorphic behavior in the
compiler where it really matters. They are always evaluated
as reals in the run time and the result/argument(s) will be
converted as needed.
The Verilog-2005 functions are available if using the 2005
generation (default) and if either the icarus-misc (also on
by default) or verilog-ams flags are set.
The Verilog-AMS functions are available if either the
icarus-misc or verilog-ams flags are set.
GCC 4.3 has tightened up header dependencies so that
`strcmp' is no longer declared if <cstdlib> is included
(which it was in prior versions). This causes the changes
in 5e512e6570 to fail to
build with 4.3.
This patch includes <cstring> in the files that are failing.
This patch adds the $clog2 system function. It also makes this
function work as a constant function. The runtime version still
needs to be updated to use an integer based version instead of
the current double based method. The double method suffers from
rounding errors.
When left-shifting unsized constants in self-determined contexts, the
constant value is normally pared down to its minimum required width.
But this practically guarantees loss of bits. Instead, detect this
special case and give the unsized constant a width of an integer.
Still allow for the super-special case that the shifted value and the
shift amount are constants. In that case, the result width (and value)
can be calculated precisely and there is no need to resort to default
widths.
This patch reworks much of the ternary code to short circuit when
possible and supports real values better. It adds a blend operator
for real values that returns 0.0 when the values differ and the value
when they match. This deviates slightly from the standard which
specifies that the value for reals is always 0.0 when the conditional
is 'bx. There are also a couple bug fixes.
These fixes have not been ported to continuous assignments yet.
Ternary operators used at compile time and in procedural assignments
should be complete (short circuit and support real values).
Rework the handling of file names to use a perm_string heap to hold
the file names, instead of the custom file name heap in the lexor.
Also rename the get_line to get_fileline to reflect its real duties.
This latter chage touched a lot of files.
I now generate the scopes and notice the parameters
in a separate pass over the pform. Once the scopes
are generated, I can process overrides and evalutate
paremeters before elaboration begins.
Stephen Williams
Nick Gasson
Cary R
Larry Doolittle
steve