OpenSPARC released

Has anyone seen Sizes / and MHz for this, finally sitting in a FPGA ? How does it compare with Leon ?

-jg

Hihi,

I was thinking about that at the time of the first announcement (a few months ago), but well I will sure look at it, and decide what todo (if).

but funny you asked, I am considering adopting some micro for one specific FPGA right now, but it would need to fit with SDRAM controller into 3000LUTs and there must be uclinux support for it. its very tight if doable using existing cores so I may end up re-writing something

Antti

Hi Pablo, Thank you for your useful information.

Weng

??

I wonder if there is any reason why it would be useful to compile the verilog for a FPGA?

Aust> For those who are interested, SUN released Open SPARC today:

I can imagine no practical use. But it sure is fun to do :).

-Isaac

Errr... To start developing and testing a SoC based on OpenSPARC interfaced to a custom digital block in an FPGA? CPU cores + FPGA blocks seem to be resurrecting now. Also, a bunch of companies are working strongly on FPAAs and other analog configurable architectures (this time done right). If we have 8051/PSoC/ARM7/PowerPC embedded cores now, why we can't dream of having devices based on a state of the art and truly open platform (GPL) in the next years? And differently from the other proprietary solutions, anyone can share ownership and help in the development of OpenSPARC...

-- PabloBleyerKocik /"But what... is it good for?" pablo / -- 1968 Engineer at IBM's Advanced Computing @bleyer.org / Systems Division, commenting on the microchip

The problem is "System Requirements": "SPARC CPU based system"

Is that for the software development environment?. Seems like the verilog rtl code should be pretty generic. From the description it sounds more like a big compute farm engine rather than something you would put in a fpga for an embedded system.

John Eaton

Why not? This would be a great teaching tool for fpga design and/or computer system design courses at college level.

~jz

Only if it can fit into an FPGA. Anybody have a gatecount?

John Eaton

Personally I think the best textbook on logic design is AMD PAL Device Handbook. All my logic training was based on the book, read by myself, not taught at any classes.

I bought 5 VHDL books, but only the AMD book really teaches me how to program in logic.

The open CPU source code is an excellent contributions to the generations of logic designers by Sun Microsystem.

It would be much wonderful If there is an retired engineer from Sun who deeply invovled in the code making writes a book with the opened source code. It would be more valuable than any Verilog books available in the market.

Teaching by example is the best way to teach a language and related technique.

Real design examples give you really deep insights on what the designers were thinking about and how nicely they handle the difficult situations.

I appreciate Sun's efforts to open its source code.

Thank you, Sun Microsystem.

Weng

The source comes with scripts for Design Compiler. I guess they want you to use that tool; which is for targetting ASICs.

Oh, and I don't have a gate count but the design is quite large:

[gliss@precision design]$ find ~/opensparc/design -name "*.v" -exec cat {} \; | wc -l 323957

There are over 320,000 lines of Verilog and the support scripts are built for a DC ASIC synthesis environment... good luck getting that to fit in an FPGA.

Chris,

Brings up a question for the group: how many lines of verilog can you fit in any given FPGA?

Anyone out there in the ASIC emulation world care to comment?

Being a 'hardware' type, I am just ignorant...

Aust> Oh, and I don't have a gate count but the design is quite large:

It's a meaningless question without considering the exact nature of the Verilog code.

For example, a complex control FSM described in several pages of code may require less than 100 gates. On the other hand, a simple (but wide) flip-flop intensive data path, described in a few lines, may require 10000 gates or more.

As for the SPARC code, it seems like an extreme example. I wouldn't call this RTL code. It's more like a manually generated technology- independent netlist. For example, they don't even use flip-flop inference. And they do have excessive hierarchy.

I suspect that it should be possible to gain at least an order of magnitude in terms of lines of code by using a proper RTL style. And the synthesis results might be better. (Excessive hierarchy tends to yield suboptimal synthesis results).

Regards,

Jan

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Jan,

OK, that makes sense. I had thought the "law of large numbers" would take over with enough code, but if this code is handcrafted for ASIC cell applications (with extremely primitive cells), then it would synthesize very poorly for anything but that application.

Aust> Aust>

I found this in design/sys/iop/sparc/ifu/rtl/sparc_ifu_rndrob.v

.... assign next_pv[0] = pv[0] | reset;

dff #4 park_reg(.din (next_pv), .clk (clk), .q (park_vec), .se (se), .si(), .so());

....

I don't see how the #4 is legal is Verilog 2001. Can someone explain to me under what it means, and under what circumstances this is legal? Is this construct part of Verilog 2001, or is it vendor specific?

-- IDB

Plain ol' verilog udp?