Signed arithmetics in Verilog: The only rule one needs to know

The golden rule is: All operands must be signed. Verilog, it seems, is strongly inclined towards unsigned numbers. Any of the following yield an unsigned value: Any operation on two operands, unless both operands are signed. Based numbers (e.g. 12′d10), unless the explicit “s” modifier is used) Bit-select results Part-select results Concatenations So the bottom [...]

Permission denied to directory, despite group permission set OK

I tried to change directory to eli from other users belonging to the group “eli” and it failed with $ cd ../eli/ -bash: cd: ../eli/: Permission denied despite everything begin OK with the classic UNIX settings. Reminder: After settings groups, there’s a need to either logout and login again, or use “su -” to refresh [...]

Workaround: “git push” from msysgit (git for Windows) hangs

I had set up my plain git-daemon and everything seemed to work fine, until I tried it from Windows. It just didn’t return from the command. According to a discussion in a newsgroup, the problem is a bug in msysgit’s implementation of side-band-64k, whatever that is. Personally, even if an upgrade to msysgit existed, or [...]

DHCP changing the IP address suddenly on embedded systems

The problem It first seemed extremely odd: The IP address of my embedded Linux machine changed suddenly after a few hours, breaking the ssh connection I had up, and messing up the NFS mount. The problem turned out to be the lack of a hardware clock (RTC) on the board + clock being updated with [...]