04-17-2018 11:06 AM
Hello,I tried to change $now back and forth in time by like: set now 1800 which seemed to have worked temporarily in the sense that one can puts "$now" and see 1800. But after run 50 it changes back to the last simulation time value. Question: Does it internally has a copy so that the actual value of $now can never be changed? greg
04-18-2018 06:39 AM
04-19-2018 05:35 AM
--- Quote Start --- I wonder not know if such jumping is possible. 1. I want to know if Modelsim supports changing the essential "now". Anyway it is a mature (more than two decades) software and the most widely used HDL simulator. I don't know if they have built this into the software. --- Quote End --- You want timetravel, that's still a bit tricky in the real world. If you want to change the viewpoint, you need to check the reference of the wave subcommands. --- Quote Start --- 2. I saw you and Tricky in another thread (https://www.alteraforum.com/forum/showthread.php?t=58437&p=237672#post237672) all used VHDL example, and you referred to an limitation of verilog in this one. --- Quote End --- I use VHDL since that's what I was thaught in university. My Verilog expertise is not great i.e. I can read and understand what's going on, but I don't know the finesses of the language and never had a reason to learn it (yet). From what I understand from people used Verilog learning/writing VHDL is that they prefer Verilog. As to why I use VHDL in my answers, think of HDL land as Belgium, one country two languages. If you meet someone in the street in Brussels (where they use both languages) which language do you use if you don't know which is spoken by the other? I would default to the language that I know, in HDL land that is VHDL, so I have nothing against using Verilog.