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Comment by amelius | Hacker News Reader

> It takes 6 lines of VHDL to backdoor a CPU

Are they still using VHDL?

I wonder what hardware languages are being used by Intel and ARM.

VHDL is used primarily in Europe (and in some academic classes in the US), while Verilog is used by the vast majority of businesses in the US, and most of the top schools for VLSI. I know that the vast majority of chip designers I know (which are 90% US based) much prefer Verilog.

As for Intel and ARM, both are primarily Verilog shops, but I know ARM provides both Verilog and VHDL models for the licensed components.

Thanks. Looking at wikipedia, Verilog stems from 1984. I'm wondering why Intel and ARM don't develop their own hardware compilers. I mean, if Mozilla can decide to start a new language, then certainly can those big companies.

Like most languages, they evolve over time. The latest version of the IEEE standard version of Verilog is Verilog 2005, but there are also offshoots, such as SystemVerilog. While most things distributed for interoperability and targeted for general understanding are written in Verilog, most actual designers use SystemVerilog, which was eventually made into its own IEEE standard. SystemVerilog adds a lot of object oriented features, and is a pretty clean addition to Verilog.

As far as why Intel, ARM, and everyone else mostly sticks to these languages is similar reason to why C is still used... it is because it works, and works good enough. After 20 years of just having Verilog, enough people agreed that it needed a update, and SystemVerilog developed. Another big reason is the fact that Intel, ARM, etc. all rely heavily on scripts and design flows that are common between pretty much every semiconductor company... all of the EDA vendors have united around these standards, and in a world where interoperability is required and very little innovation happens on the backend tools, people stick to what works.

Intel used "iHDL" which was an in-house language from 1986 to 2005, and after 2005 switched mainly to Verilog.

You usually see VHDL in .eu and some defense contractors, and Verilog everywhere else. VHDL feels similar to Ada, and Verilog is more similar to C.

An interesting history from Intel's perspective is available here: http://webee.technion.ac.il/people/kolodny/ftp/IntelCADPaper...

A lot of companies still use VHDL to write IPs.

Systemverilog is the de facto standard in verification, but VHDL with its strong typing remains a favorite for writing synthesizable code.

ARMs customer facing code is 100% verilog and this reflects most of the industry.

They do provide VHDL models for at least some components I have seen, but Verilog is what they do seem to prefer)

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