Information on LEON3 Simulation

http://tech.groups.yahoo.com/group/leon_sparc/message/12106

Re: [leon_sparc] Running test program on leon in modelsim

You do not want to simulate a mkprom image in VHDL, trust me.
Even the smallest image will execute ~ 1,000,000 instructions
before entering main() in RAM. This is only ~ 30 ms on real
hardware at 50 MHz, but ~ 10 hours in VHDL (on a fast host).

You can easily see in TSIM how many instructions you will need:

sparc-elf-gcc -msoft-float hello.c -o hello.exe -lsmall
sparc-elf-mkprom hello.exe -nocomp -nomsg

tsim-leon3 prom.out
.
.
section: .text, addr: 0×0, size 34304 bytes
read 103 symbols
tsim> bre 0×40000000
breakpoint 1 at 0×40000000: .bdata
tsim> run
breakpoint 1 .bdata
tsim> per

Cycles : 1399497
Instructions : 906783
Overall CPI : 1.54

CPU performance (50.0 MHz) : 32.40 MOPS (32.40 MIPS, 0.00 MFLOPS)
Cache hit rate : 98.7 % (100.0 / 80.0)
AHB bandwidth utilisation : 33.7 % ( 0.4 / 33.3)
Simulated time : 27.99 ms
Processor utilisation : 100.00 %
Real-time performance : 11.86 %
Simulator performance : 3843.69 KIPS
Used time (sys + user) : 0.24 s

So even if we created the smallest possible binary using -lsmall
and fastest mkprom loading with -nomsg and -nocomp, you will need
to execute 906,783 instructions to get to RAM, and then maybe an
other 10,000 to get to main(). This is why the test bench in leon3
designs does NOT use mkprom, but a simple assembly reset sequence
and a pre-loaded RAM image…

Jiri.

sacliv wrote:
> Hey guys, I’m trying to load a test c program i wrote on the leon3 in
> the vhdl leon3 code and run it in modelsim to view the waveforms.
>
> I followed the bcc manual and did mkprom on my executable, and then i
> copied the .srec file to the testbench directory, and in the
> testbench.vhd, i changed the filename of the prom.srec to test.srec,
> which is my srec file.
>
> The test program is very simple and just prints out hello world, but
> in the modelsim simulation of the leon3, i’m watching the pc and
> instructions of the leon3 core, but i can’t seem to get to my test
> program.
>
> Does anyone know either how long i have to simulate it until before i
> get to main() in my test program? Or if i’m doing it wrong, what’s the
> correct procedure? Thanks!

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http://tech.groups.yahoo.com/group/leon_sparc/message/12108

Re: [leon_sparc] Re: Running test program on leon in modelsim

See how the test bench is compiled by doing ‘make soft’ in the
template design directory. The final command will be:

sparc-elf-gcc -I../../software/leon3 -O2 -g -msoft-float systest.c -L./
lib3tests.a -o systest.exe
sparc-elf-objcopy -O srec systest.exe sram.srec

You can do pretty much the same using your own application:

sparc-elf-gcc -O2 -g -msoft-float myapp.c -o myapp.exe
sparc-elf-objcopy -O srec myapp.exe sram.srec

And make sure you understand how to use the ‘volatile’ keyword
in C if you intend to do any memory tests or similar …

Jiri.

sacliv wrote:
> Wow that’s good to know. So is there a way to easily simulate my test
> code using the leon3 VHDL code?

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http://tech.groups.yahoo.com/group/leon_sparc/message/12114

Re: [leon_sparc] Re: Running test program on leon in modelsim

You can run your code from PROM for fastest run-time. Copy prom.S
from software/leon3 to you local template design, and do ‘make soft’.
Then, add your instructions just before the code jumps to RAM at
the end of the file:

set RAMSTART, %g1
<–insert here
jmp %g1
nop

Do a ‘make soft’ again, and restart simulation. Note that you can
get assembly output from the simulation by setting the disas generic
to 1 (or start modelsim with -gdisas=1) .

Jiri.

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http://www.gaisler.com/cms/index.php?option=com_content&task=view&id=92&Itemid=66

How do I put the content of a file “as is” into the .data section (or somewhere else into memory)?
You can add a binary file to an existing elf file with objcopy, by adding a new section and fill it with the desired content:

sparc-elf-objcopy –add-section .myelfsection=file.bin –change-section-address .myelfsection=0×00001000

–set-section-flags .myelfsection=alloc,contents,load,data file.exe

The example above adds the file ‘file.bin’ to the elf file ‘file.exe’ at address 0×1000. Note that this is done after linking.

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