Hi,

sorry for delay.
thank you for the info, christophe.curis@ and diogratia@.

> And ya, I apologize for being verbose.

no problem, this is very informative to me.

> In the mean time Mr. Masaru please file a bug on gna
> (https://gna.org/support/?group=ghdl&func=additem)
> (and yes the certificate is wonky, it's okay).
> It'd be worth archiving the oisc test case for inclusion, too.
> It may not be available on bitbucket by the time someone takes it seriously.

you already filed a bug w/ my source code at https://gna.org/bugs/?18810
of course, you can use my code for what ever you want to.

> I take it this a Xilinx dual port memory?

i wrote this just for fun, is not implementation proposed though.

and yes, XST 13.2 can synthesize not only LVT_DMEM = true but also
LVT_DMEM = false.

FYI, "XST User Guide for Virtex-6, Spartan-6, and 7 Series Devices
UG687 (v 13.2) July 6, 2011 on " said,

Modeling a RAM in VHDL (Two Write Ports)
To model a RAM with two write ports in VHDL, use a shared variable
instead of a signal.
type ram_type is array (0 to 255) of std_logic_vector (15 downto 0);
shared variable RAM : ram_type;
• XST rejects an attempt to use a signal to model a RAM with two write
ports. Such a
model does not behave correctly during simulation.
• Shared variables are an extension of variables, allowing inter-process
communication.
– Use shared variables with even greater caution than variables.
– Shared variables inherit all basic characteristics from variables.
– The order in which items in a sequential process are described can
condition the
functionality being modeled.
– Two or more processes making assignments to a shared variable in the same
simulation cycle can lead to unpredictable results.
• Although shared variables are valid and accepted by XST, do not use a shared
variable if the RAM has only one write port. Use a signal instead.

and I saw LVT method on comp.lang.vhdl,
http://groups.google.com/group/comp.arch.fpga/browse_thread/thread/d12f605d8f3c1fc5?hl=en

Peace,

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