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Can nios_gnupro support file system?

Hi, can any body explain to me does the nios_gnupro support any functions that manage files or other input/output streams??? I am currently using the Altera Nios Developed Board during my research which is Apex Device (EP20K200EFC484-2x). But i failed to execute a very simple program which just consist of fopen and fclose as follows:

#include

main() { FILE *a; a = fopen("simple.dat", "w"); fclose(a); return 0; }

i have compile this program using Visual Studio, and the output is correct. But once i execute the nios-build in the Nios SDK shell, it keep giving me the following errors:

in function `_open_r': openr.o(.text+0x14): undefined reference to `_open' openr.o(.text+0x16): undefined reference to `_open' openr.o(.text+0x18): undefined reference to `_open' openr.o(.text+0x1a): undefined reference to `_open'

Can anybody explain to me where is my problem? Thanks a lot and wish you all have a nice day.

Reply to
Jasmine Hau
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Where are you expecting this file to be? Which operating system is running on the Nios, and providing access to a file system? File access is a service that needs to be provided by an operating system, or emulated in some way - without that, the program has no more chance of openning a file than it has of drawing a window on the screen.

Functions such as fopen and fclose are required parts of the standard c library, but since there is no sensible way to implement them on most embedded systems, they are often stubbed out (i.e., they do nothing, as is the case for fclose), or are missing entirely from the library files (as is the case for _open).

Reply to
David Brown

In many embedded system, a memory file system is used. MicroBlaze and EDK is shipped with a memory file system.

Göran Bilski

Reply to
Goran Bilski

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Yes, that's the most common way to implement working file functions on embedded systems without a reasonably complete OS with a real file system somewhere. The file functions are simply implemented in library functions. I don't know if there are such library functions in the Nios kit - I haven't looked at everything on it yet.

Reply to
David Brown

Hi,I am currently doing research on the Elliptic Curve Cryptosystem (ECC) on Smart Card Prototype. I will build a ECC Smart card prototype and download the entire design into Altera FPGA APEX Device which is EP20K200EFC484-2x. This prototype does not have an embedded OS. To test and verify my design, I will build a testbench for Elliptic Curve Digital Signature and ECC-based Mutual Authentication. Currently, the Operating System on my PC is Windows2000 with NTFS File System. My Altera Nios Development Board communicates with the PC through UART. To build the testbench, i need to write a software which will be built and run on the Nios SDK shell and able to do the following functions: 1. Open a new file or read a existing file (plain-text) in the Operating System Windows2000 environemnt in my PC. 2. The file will be sent from my PC to my Smart Card prototype through UART. 3. The file (plaintext) will be processed in my Smart Card prototype to create a Digital Signature. 4. Both of the original file (plaintext) and the digital signature will then sent back to PC from smart card prototype through UART.

My question is: Does the Nios-gnupro support the file access system such as fopen, fprintf, fclose? I have written a simple program which is able to run on Visual Studio but can't execute while in nios-build process. I wonder does the Nios-gnupro support the file access system. Thanks for your reply. Wish you all have a nice day.

Reply to
Jasmine Hau

I think you are confusing the issues here quite significantly. The OS you have on your PC is basically irrelevant - when I asked what OS you had, I meant what OS your embedded processor is running - and the answer is none. So unless you implement (or find) functions to create a virtual file system in the Nios's local memory, then it has no fopen, etc., functions. Even with such memory-based file access, it would not give you what you want.

Forget file access for the Nios - it is not what you are looking for. You need something running on the PC which accesses files there, and sends them through the UART to the Nios board. The Nios program must take its data from the UART, not through fopen, and send its results back through the UART. Unless you need the Nios program to be able to choose the files itself, you can probably do this using a simple terminal program on the PC (maybe the nios-run terminal, or download something like Tera Term Pro or RealTerm). If you need more than that, you can write a PC program to handle the file access and send data back and forth across the UART.

Reply to
David Brown

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