FPGA Central

I'm stumped. Ideas welcomed.

I'm trying to write a SystemVerilog DPI application that
interacts with the simulator console and, in just one of
the simulators I use, I can't get a prompt to appear on
the same line as user input at the console. Here's a
sketch of the DPI import function written in C:

void called_from_Verilog() {
char s[200];
io_printf("This line is displayed OK\n");
io_printf("This prompt doesn't appear correctly: ");
gets(s);
io_printf("You typed :%s:", s);
}

One major simulator doesn't flush the console's output buffer
on a gets() call, so I don't see the prompt correctly. If
I use printf() instead of io_printf(), things go even worse;
but that's perhaps not too surprising.

On two other simulators it works as I would hope, with the
prompt being flushed to stdout before the user starts typing.

Adding a fflush() or vpi_flush() call just before the gets()
has no effect that I can discern.

Does anyone know a really robust way to do this?

Thanks in advance
--
Jonathan Bromley, Consultant

DOULOS - Developing Design Know-how
VHDL * Verilog * SystemC * e * Perl * Tcl/Tk * Project Services

Doulos Ltd., 22 Market Place, Ringwood, BH24 1AW, UK
[email protected]
http://www.MYCOMPANY.com

The contents of this message may contain personal views which
are not the views of Doulos Ltd., unless specifically stated.

I would suggest filing a bug to the tool vendor.

I would have expected vpi_flush to occomplish what you want to have happen.

If you file a bug against it. Thier developers can give you a workaround.
You may be able to use the workaroun as a robust method in the future.
Before you mentioned this problem I would have said using vpi_flush was the
robust method.

"Jonathan Bromley" <[email protected]> wrote in message
news:[email protected]..
> I'm stumped. Ideas welcomed.
>
> I'm trying to write a SystemVerilog DPI application that
> interacts with the simulator console and, in just one of
> the simulators I use, I can't get a prompt to appear on
> the same line as user input at the console. Here's a
> sketch of the DPI import function written in C:
>
> void called_from_Verilog() {
> char s[200];
> io_printf("This line is displayed OK\n");
> io_printf("This prompt doesn't appear correctly: ");
> gets(s);
> io_printf("You typed :%s:", s);
> }
>
> One major simulator doesn't flush the console's output buffer
> on a gets() call, so I don't see the prompt correctly. If
> I use printf() instead of io_printf(), things go even worse;
> but that's perhaps not too surprising.
>
> On two other simulators it works as I would hope, with the
> prompt being flushed to stdout before the user starts typing.
>
> Adding a fflush() or vpi_flush() call just before the gets()
> has no effect that I can discern.
>
> Does anyone know a really robust way to do this?
>
> Thanks in advance
> --
> Jonathan Bromley, Consultant
>
> DOULOS - Developing Design Know-how
> VHDL * Verilog * SystemC * e * Perl * Tcl/Tk * Project Services
>
> Doulos Ltd., 22 Market Place, Ringwood, BH24 1AW, UK
> [email protected]
> http://www.MYCOMPANY.com
>
> The contents of this message may contain personal views which
> are not the views of Doulos Ltd., unless specifically stated.

On Feb 19, 2:53 pm, "Dwayne Dilbeck" <ddilb...@yahoo.com> wrote:
> I would suggest filing a bug to the tool vendor.
>
> I would have expected vpi_flush to occomplish what you want to have happen.
>
> If you file a bug against it. Thier developers can give you a workaround.
> You may be able to use the workaroun as a robust method in the future.
> Before you mentioned this problem I would have said using vpi_flush was the
> robust method.
>
> "Jonathan Bromley" <jonathan.brom...@MYCOMPANY.com> wrote in message
>
> news:[email protected]..
>
> > I'm stumped. Ideas welcomed.
>
> > I'm trying to write a SystemVerilog DPI application that
> > interacts with the simulator console and, in just one of
> > the simulators I use, I can't get a prompt to appear on
> > the same line as user input at the console. Here's a
> > sketch of the DPI import function written in C:
>
> > void called_from_Verilog() {
> > char s[200];
> > io_printf("This line is displayed OK\n");
> > io_printf("This prompt doesn't appear correctly: ");
> > gets(s);
> > io_printf("You typed :%s:", s);
> > }
>
> > One major simulator doesn't flush the console's output buffer
> > on a gets() call, so I don't see the prompt correctly. If
> > I use printf() instead of io_printf(), things go even worse;
> > but that's perhaps not too surprising.
>
> > On two other simulators it works as I would hope, with the
> > prompt being flushed to stdout before the user starts typing.
>
> > Adding a fflush() or vpi_flush() call just before the gets()
> > has no effect that I can discern.
>
> > Does anyone know a really robust way to do this?
>
> > Thanks in advance
> > --
> > Jonathan Bromley, Consultant
>
> > DOULOS - Developing Design Know-how
> > VHDL * Verilog * SystemC * e * Perl * Tcl/Tk * Project Services
>
> > Doulos Ltd., 22 Market Place, Ringwood, BH24 1AW, UK
> > jonathan.brom...@MYCOMPANY.com
> >http://www.MYCOMPANY.com
>
> > The contents of this message may contain personal views which
> > are not the views of Doulos Ltd., unless specifically stated.

If this were C, the gets call should force a flush. I'd tend to agree
it's a bug...

On Sun, 17 Feb 2008 22:42:36 +0000, Jonathan Bromley wrote:

>I'm stumped. Ideas welcomed.

Thanks for the suggestions, guys; I'll see what the
tool vendor has to say.
--
Jonathan Bromley, Consultant

DOULOS - Developing Design Know-how
VHDL * Verilog * SystemC * e * Perl * Tcl/Tk * Project Services

Doulos Ltd., 22 Market Place, Ringwood, BH24 1AW, UK
[email protected]
http://www.MYCOMPANY.com

The contents of this message may contain personal views which
are not the views of Doulos Ltd., unless specifically stated.