How to compile and simulate DPI C file with Questasim?

[kansagaratushar]

I don't know how to compile and simulate DPI C file with Questasim. So Can you please give compilation process for the same.
Thanks in advance..

 

[meir]

You need to import the function in your sv code:

import "DPI" function int get_pid();
import "DPI" function int get_vmem( output string output_str_ptr );

Questasim will compile c files with vlog so you need to just add the files in your "do" file

 

[kansagaratushar]

I didn't get it. Can you please write down compilation process for questasim for following example:

............................CODE: SV_file .................................
program main;
string str;

import "DPI-C" string_sv2c=task string_sv2c();

initial
begin
string_sv2c();
end

endprogram


................................CODE: C_file .......................................
#include "svdpi.h"

void string_sv2c(){
printf(" C: Hellow from C ");
}

 

[meir]

change
import "DPI-C" string_sv2c=task string_sv2c();
to
import "DPI-C" string_sv2c=function void string_sv2c();

(you don't have to rename the function and I think it's better to move the import declaration out of the program)

for files string_sv2c.sv & string_sv2c.c
run :
vlib work
vlog -sv string_sv2c.sv string_sv2c.c
vsim -c work.main -do "run -all"

 

[dave_59]

A couple of things to mention for future reference:

• Do not use the -sv switch. *.sv files are already treated as SystemVerilog and using -sv will make legacy Verilog *.v files compile as SystemVerilog. This may cause errors if SV keywords are used in Verilog files.
• Use void functions instead of tasks for procedures that do not consume time(block), for both pure SV and DPI usage. Calling a function is a guarentee that the procedure will not consume time, and there is less overhead associated with that kind of call.
• Use vlog -dpiheader filename.h when compiling SV DPI code. That generates a header file that you should #include "filename.h" in your DPI C code. This gives you compile time checking that your C procedures have the correct argument types. Otherwise you may get run-time fatal errors from bad memory references.

 

[kansagaratushar]

Thanks.....Its Done....

 

[hirenpatel]

thx..............

 

[rangapura]

vlog -dpiheader dpi_header_file.h ../Verification/verificationcodes/dpi/dpi_test.sv ../Verification/verificationcodes/dpi/dpi_c.c
# QuestaSim vlog 10.0b Compiler 2011.05 May 5 2011
# -- Compiling program main
#
# Top level modules:
# main

vsim -c main -do "run -all"
# vsim -do {run -all} -c main
# ** Note: (vsim-3813) Design is being optimized due to module recompilation...
# Loading sv_std.std
# Loading work.main(fast)
# ** Warning: (vsim-3770) Failed to find user specified function 'string_sv2c'. The search list was empty.
# Using -sv_lib, -sv_root, and -sv_liblist arguments can provide a search list
# of shared libraries that will be used to resolve user specified functions.
# Time: 0 ns Iteration: 0 Instance: /main File: ../Verification/verificationcodes/dpi/dpi_test.sv
# run -all
# ** Fatal: (vsim-160) ../Verification/verificationcodes/dpi/dpi_test.sv(5): Null foreign function pointer encountered when calling 'string_sv2c'
# Time: 0 ns Iteration: 0 Process: /main/#INITIAL#8 File: ../Verification/verificationcodes/dpi/dpi_test.sv
# Fatal error at ../Verification/verificationcodes/dpi/dpi_test.sv line 5
#
# HDL call sequence:
# Stopped at ../Verification/verificationcodes/dpi/dpi_test.sv 5
# called from ../Verification/verificationcodes/dpi/dpi_test.sv 10

Getting this errors........

***********C Code********
#include"svdpi.h"
#include"F:\prepare\Verification\dpi_header_file.h"
void string_sv2c()
{
printf(" C: Hellow from C ");
}


**********SV Code***********
program main;
string str;
import "DPI-C" string_sv2c=function void string_sv2c();


initial
begin
string_sv2c();
end

endprogram



pls hlp...

 

[hirenpatel]

your above code is write
in c file what you write in 2nd line?
remove 2nd line and run it will work

 

[rangapura]

your above code is write
in c file what you write in 2nd line?
remove 2nd line and run it will work

thnks fr rply...
yah i have tryd dat one also but its giving same error....

 

[hirenpatel]

after removing 2nd line what error it will give?

 

[dave_59]

The output from vlog should have been

$ vlog -dpiheader dpi_header_file.h dpi_test.c dpi_test.sv
QuestaSim vlog 10.2a Compiler 2013.03 Mar 15 2013
-- Compiling program main

Top level modules:
        main
[COLOR="#FF0000"]-- Compiling DPI C/C++ file dpi_test.c[/COLOR]

Try putting everything in the same directory so there are no differences between cygwin and windows paths. If that doesn't work, you may need to compile your C files directly with gcc.

Also, you can simplify your import statement when the name in SV and C are the same.

import "DPI-C" function void string_sv2c();

 

[rangapura]

The output from vlog should have been

$ vlog -dpiheader dpi_header_file.h dpi_test.c dpi_test.sv
QuestaSim vlog 10.2a Compiler 2013.03 Mar 15 2013
-- Compiling program main

Top level modules:
        main
[COLOR="#FF0000"]-- Compiling DPI C/C++ file dpi_test.c[/COLOR]

Try putting everything in the same directory so there are no differences between cygwin and windows paths. If that doesn't work, you may need to compile your C files directly with gcc.

Also, you can simplify your import statement when the name in SV and C are the same.

import "DPI-C" function void string_sv2c();

as u said i just put every file in the same path

---------C - File -------------
#include"svdpi.h"
#include"dpi_header_file.h"
void string_sv2c()
{
printf(" C: Hellow from C ");
}

--------sv file-----

program main;
string str;
import "DPI-C" function void string_sv2c();


initial
begin
string_sv2c();
end

endprogram


vlib work
vlog -dpiheader dpi_header_file.h dpi_test.c dpi_test.sv
# QuestaSim vlog 10.0b Compiler 2011.05 May 5 2011
# -- Compiling program main
#
# Top level modules:
# main


vsim -c work.main
# vsim -c work.main
# ** Note: (vsim-3812) Design is being optimized...
# Loading sv_std.std
# Loading work.main(fast)
# ** Warning: (vsim-3770) Failed to find user specified function 'string_sv2c'. The search list was empty.
# Using -sv_lib, -sv_root, and -sv_liblist arguments can provide a search list
# of shared libraries that will be used to resolve user specified functions.
# Time: 0 ns Iteration: 0 Instance: /main File: dpi_test.sv


and getting this error....

- - - Updated - - -

The output from vlog should have been

$ vlog -dpiheader dpi_header_file.h dpi_test.c dpi_test.sv
QuestaSim vlog 10.2a Compiler 2013.03 Mar 15 2013
-- Compiling program main

Top level modules:
        main
[COLOR="#FF0000"]-- Compiling DPI C/C++ file dpi_test.c[/COLOR]

Try putting everything in the same directory so there are no differences between cygwin and windows paths. If that doesn't work, you may need to compile your C files directly with gcc.

Also, you can simplify your import statement when the name in SV and C are the same.

import "DPI-C" function void string_sv2c();

as u said i just put every file in the same path

---------C - File -------------
#include"svdpi.h"
#include"dpi_header_file.h"
void string_sv2c()
{
printf(" C: Hellow from C ");
}

--------sv file-----

program main;
string str;
import "DPI-C" function void string_sv2c();


initial
begin
string_sv2c();
end

endprogram


vlib work
vlog -dpiheader dpi_header_file.h dpi_test.c dpi_test.sv
# QuestaSim vlog 10.0b Compiler 2011.05 May 5 2011
# -- Compiling program main
#
# Top level modules:
# main


vsim -c work.main
# vsim -c work.main
# ** Note: (vsim-3812) Design is being optimized...
# Loading sv_std.std
# Loading work.main(fast)
# ** Warning: (vsim-3770) Failed to find user specified function 'string_sv2c'. The search list was empty.
# Using -sv_lib, -sv_root, and -sv_liblist arguments can provide a search list
# of shared libraries that will be used to resolve user specified functions.
# Time: 0 ns Iteration: 0 Instance: /main File: dpi_test.sv


and getting this error....

 

[dave_59]

You need a slightly newer version of Modelsim/Questa to auto-compile C code from the vlog command line on Windows. Either update your version, or see "Registering DPI Applications" in the User Manual.

 

[hirenpatel]

compile with

vlog c-file.c sv-file.sv

 

[aptronics]

Were these errors solved?

I am getting the same error when I try to run a simple "Hello World" program.
I am using the Questa 10.0b version.
Tried to compile the C program using gcc and getting some compile errors.

---System Verilog program ---
// Named as hello.sv
module top;

// Declare the DPI import function
import "DPI-C" function void hello(string str);

initial begin
hello("Hello World") ;
end

endmodule
---End of SV program---------
---Start of C program -----------
//Named as hello.c
#include <stdio.h>

void hello(char* str)
{
printf ("%s\n", str) ;
}

--End of C program ----
// Compile Steps //

vlog hello.sv
# QuestaSim vlog 10.0b Compiler 2011.05 May 5 2011
# -- Compiling module top
#
# Top level modules:
# top

gcc -shared -Bsymbolic -o hello.so hello.c
vsim -sv_lib hello top

# vsim -sv_lib hello top
# ** Error: (vsim-3763) SystemVerilog DPI cannot access file '.\hello.dll'
# No such file or directory. (errno = ENOENT)
# Time: 0 ns Iteration: 0 Unknown: <UNKNOWN>
# Use the -help option for complete vsim usage.
# Error loading design

I am confused whether the vsim is expection a .so file or not.
Any answers?

Thanks.

 

[dave_59]

If you are running on windows, then change -o hello.so to -o hello.dll.

Also, we strongly recommend that you create a dpi header file.

 vlog hello.sv -dpiheader hello.h

Then #include "hello.h" inside your C file.

 

[aptronics]

Thanks Dave. The simulation error disappeared, but the output is still missing.

vlog hello.sv
# QuestaSim vlog 10.0b Compiler 2011.05 May 5 2011
# -- Compiling module top
#
# Top level modules:
# top
gcc -shared -Bsymbolic -o hello.dll hello.c
vsim -sv_lib hello top
# vsim -sv_lib hello top
# ** Note: (vsim-3813) Design is being optimized due to module recompilation...
# Loading sv_std.std
# Loading work.top(fast)
# Loading .\hello.dll
run -all

I tried with the dpiheader option also.
vlog hello.sv -dpiheader dpiheader.h
# QuestaSim vlog 10.0b Compiler 2011.05 May 5 2011
# -- Compiling module top
#
# Top level modules:
# top

But the compilation of C file in the next step ended in error.

gcc -shared -Bsymbolic -o hello.dll hello.c
# hello.c:5:6: error: conflicting types for 'hello'
# In file included from hello.c:2:0:
# dpiheader.h:27:1: note: previous declaration of 'hello' was here

//DPI header contents are pasted below
--- dpiheader starts here -----------
#ifndef INCLUDED_DPIHEADER
#define INCLUDED_DPIHEADER

#ifdef __cplusplus
#define DPI_LINK_DECL extern "C"
#else
#define DPI_LINK_DECL
#endif

#include "svdpi.h"


DPI_LINK_DECL DPI_DLLESPEC
void
hello(
const char* str);

#endif
--- dpiheader ends here -----------

The C program seems to be working fine when I ran independently.

 

[dave_59]

The output should have gone to stdout. If you want the output to go to the transcript or log files as well, you will need to use vpi_printf() instead of printf(). You will need to #include "vpi_user.h" to pick up the VPI routines.

The conflicting types for 'hello' message you got is exactly the kind of message using -dpiheader should be giving you. It means your C code did not match the expected prototype fro the function hello. The str argument should have been declare const char* str to prevent the C code from modifying the string. This is not a problem in your simple code example, but I hope you can see how a conflicting type could become a hard to debug run-time error hand you not caught it at compile time.

 

[aptronics]

Thanks Dave.

Changed it to const char* in C program and the conflicting type error disappeared. Pretty good utility this header inclusion

Still I dint get the output on my transcript because of a gcc error. (I have not used verilog PLI/VPI. Started directly with DPI). I included the "vpi_user.h" and the "vpi_compatibility.h". Is there anything else I need to add to get the vpi_printf function? (Using Windows + Questa 10.0b).
---------Modified C program ---------------
#include "vpi_user.h"
#include "dpiheader.h"


void hello(const char* a)
{
vpi_printf("%s\n",a);
}
-----------End of C program ---------------



vlog -dpiheader dpiheader.h hello.sv
# QuestaSim vlog 10.0b Compiler 2011.05 May 5 2011
# -- Compiling module top
#
# Top level modules:
# top
gcc -shared -Bsymbolic -o hello.dll hello.c
# C:\Users\..\AppData\Local\Temp\ccyjsdv0.o:hello.c.text+0x15): undefined reference to `vpi_printf'
# collect2.exe: error: ld returned 1 exit status


I tried the qverilog option (after changing to const char*) and then got the output comfortably.
But still at a loss after trying to compare what qverilog did with what I should have done for it to work without using qverilog.

QuestaSim qverilog 10.0b Compiler 2011.05 May 5 2011
C:\questasim_10.0b\win32\qverilog.exe -reportprogress 300 -guimode hello.sv hello.c
-- Compiling module top

Top level modules:
top
+ C:\questasim_10.0b\win32/vsim -lib work top -c -do "run -all; quit -sim" -appendlog -l qverilog.log -vopt -sv_lib work/_dpi/qv_dpi
modules:
# top
# + C:\questasim_10.0b\win32/vsim -lib work top -c -do "run -all; quit -sim" -appendlog -l qverilog.log -vopt -sv_lib work/_dpi/qv_dpi
vsim -lib work top -c -do {run -all; quit -sim} -appendlog -l qverilog.log -vopt -sv_lib work/_dpi/qv_dpi
# vsim -appendlog -do {run -all; quit -sim} -l qverilog.log -lib work -c -vopt -sv_lib work/_dpi/qv_dpi top
# Loading sv_std.std
# Loading work.top(fast)
# Loading .\work/_dpi/qv_dpi.dll
# run -all
# Hello System Verilog
# quit -sim