Nios II Command Shell

Starting the Nios II Command Shell brings up a console window in a UNIX-like environment.

Windows File Systems

The Windows directories are attached to the /cygdrive directory. The C directory, for example, is linked to /cygdrive/c.

Root Directory

The root directory is mapped to a Quartus directory. On my system it is C:\altera\72sp1\quartus\bin\cygwin.

Path

The search path, where the system looks for executable files, can be obtained as follows:

[SOPC Builder]$ echo $PATH
/cygdrive/c/altera/72/nios2eds/bin:/cygdrive/c/altera/72/nios2eds/bin/nios2-gnut
ools/H-i686-pc-cygwin/bin:/cygdrive/c/altera/72/nios2eds/sdk2/bin:/cygdrive/c/al
tera/72/nios2eds/bin/fs2/bin:/bin:/usr/bin:/cygdrive/c/altera/72sp1/quartus/win
    ... output truncated ...

The usual Windows path is included in the colon-delimited list. The first few directories in the list are:

/cygdrive/c/altera/72/nios2eds/bin:
/cygdrive/c/altera/72/nios2eds/bin/nios2-gnutools/H-i686-pc-cygwin/bin:
/cygdrive/c/altera/72/nios2eds/sdk2/bin:
/bin:
/usr/bin:
/cygdrive/c/altera/72sp1/quartus/win:

Console Window

Below is a screen image of the Nios II Console:

You can mark and copy a portion of the console window by pressing the right mouse button with the mouse cursor in the title bar (not the client window). Select Edit - Mark, drag the mouse to select a region, then press the enter key. You can then paste the selection into another document.

The advantage of copying text from the console window is that the resulting content is generally more readable and avoids the black background of a screen capture, as shown below.

------------------------------------------------ Welcome To Altera SOPC Builder Version 7.2, Built Tue Nov 20 21:50:25 PST 2007 ------------------------------------------------ ------------------------------------------------ Welcome to the Nios II Embedded Design Suite Version 7.2, Built Tue Nov 20 23:27:29 PST 2007 Example designs can be found in /cygdrive/c/altera/72/nios2eds/examples ------------------------------------------------ (You may add a startup script: c:/altera/72/nios2eds/user.bashrc) /cygdrive/c/altera/72/nios2eds/examples [SOPC Builder]$

Change Directory

The Nios II Console is “unix-style”. Directory paths are separated by a forward slash (/). The following example changes the directory to the c-drive and then uses pwd to “print the working directory”.

[SOPC Builder]$ cd /cygdrive/c
/cygdrive/c
[SOPC Builder]$ pwd
/cygdrive/c
/cygdrive/c
[SOPC Builder]$

From here, change directory to one where a Nios II executable file (.elf) is stored. For example:

cd nios2lab1/software/hello_world_small_0/release.

Console Tools

Most Nios II tools are designed to run from the console. For example, to obtain the size of an executable program:

[SOPC Builder]$ nios2-elf-size hello_world_small_0.elf
   text    data     bss     dec     hex filename
    652      16       0     668     29c hello_world_small_0.elf

To show the main header of an excutable (.elf) file:

[SOPC Builder]$ nios2-elf-readelf -h hello_world_small_0.elf
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 ff 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            Standalone App
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Altera Nios II
  Version:                           0x1
  Entry point address:               0x8020
  Start of program headers:          52 (bytes into file)
  Start of section headers:          14180 (bytes into file)
  Flags:                             0x0
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         2
  Size of section headers:           40 (bytes)
  Number of section headers:         20
  Section header string table index: 17

You can redirect output to a file, which can then be edited, and inserted into a document. For example, to generate a disassembly listing:

[SOPC Builder]$ nios2-elf-objdump -d hello_world_small_0.elf > hello.da.txt

The output file, hello.da.txt was edited to the following excerpt (main program):

0000806c <main>:
    806c:	deffff04 	addi	sp,sp,-4
    8070:	01000074 	movhi	r4,1
    8074:	21209d04 	addi	r4,r4,-32140
    8078:	dfc00015 	stw	ra,0(sp)
    807c:	00081780 	call	8178 <alt_putstr>
    8080:	003fff06 	br	8080 <main+0x14>

Shell Scripts

Collections of useful operations can be collected into a “shell script” that can be run from the console. For example, type (or download demo.zip) the following script into a file called demo.sh:

#!/bin/sh
inp="hello_world_small_0"
oup="hi_world"
nios2-elf-size ${inp}.elf > ${oup}.size.txt
nios2-elf-readelf -h ${inp}.elf > ${oup}.program.txt
nios2-elf-objdump -dS ${inp}.elf > ${oup}.da.txt
echo done

To run the script, enter

./demo.sh

Maintained by John Loomis, last updated 15 September 2008