Trying another example

[inttuser]

Observed Behavior

Hello, I wanted to try another example based on ibex_simple_system (specifically hello_test). I added my .c files to the common and hello_test directories—following the existing pattern—and rebuilt everything. The code uses the puts function; in the log file, I can see the output from puts, but I also see an exception. Upon investigating the cause of the exception, I found this:

Could you tell me where this problem might be coming from?

Expected Behavior

Steps to reproduce the issue

My Environment

EDA tool and version:

I used Siemens Questa sim tool. version 2024.2

Operating system:

Version of the Ibex source code:

[SamuelRiedel]

Hi @inttuser. Looking at the graphics, it appears that half of the word coming out of the RAM is valid, while the other half is X. Specifically, a read at address 0xcff6 is returning 0x0006XXXX, right?

My main suspicion is that your program is simply reading at the very boundary of the initialized RAM. Since the X states are propagating directly out of the RAM module itself, an uninitialized memory region is the most likely culprit here.

To narrow this down, I'd recommend inspecting your compiled binary and your preloaded memory file in more detail. Check what data is actually placed around address 0xcff6. I suspect that your initialization data ends right in the middle of that word.

Good luck!