Talk:SPARC/Archives/2017

This is an archive of past discussions about SPARC. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

DFP

There is a claim that some Fujitsu SPARC processors have hardware implementations of decimal floating point. I don't see a reference for this, though, so I looked here. Does anyone here know about that? Gah4 (talk) 20:52, 18 September 2017 (UTC)

I presume you have seen Decimal_floating_point ("Fujitsu also has Sparc processors with DFP in hardware").

I have never seen any definitive reference to DFP op-codes for any Fujitsu SPARC processor, but given Fujitsu ported their BS2000/OSD mainframe operating system (inherited from Siemens) to SPARC in the early 2000s, it would not be totally surprising to find they had either customised cores, or DFP co-processors (using the traditional SPARC co-processor interface) lurking in their SX series mainframes somewhere - Fujitsu SX mainframes might be a good place to start looking.

Secondly, the SPARC64V was loosely based on the 1999 Fujitsu GS8900 (non-SPARC) mainframe processor, so *just might* therefore have some poorly-documented DFP capabilities hidden away somewhere, perhaps only available when loaded with "mainframe" microcode.

The (Fujitsu) MB86900, microSPARC-II and TurboSPARC did not have DFP in hardware (except possibly using an external co-processor).

Good luck with your search, remember to post any interesting results back here. Shelldozer (talk) 11:08, 19 September 2017 (UTC)

Soft-Cores versus Concrete Implementations

Not too happy that "LEON4" is in the main table, with most of the fields blanked out (because it is a ***configurable*** VHDL "soft-core" rather than an actual microprocessor). Replacing it with a concrete implementation, eg: Cobham Gaisler GR740, where the data-fields *can* be filled-in, sounds like a better way to go.

Perhaps this page should have a separate summary paragraph listing the known SPARC soft-cores: OpenSPARC T1/T2; ERC32; the LEON series (with a link to the LEON Wikipedia article for the gory details); and so on. Shelldozer (talk) 12:34, 19 September 2017 (UTC)

Thoughts?

Alternative suggestion: could use eg: LEON4 or LEON3 as the generic-/code-name ("micro-architectural name"), and eg: GR740 or GR712RC as the specific model name ("concrete implementation name"). Shelldozer (talk) 12:34, 19 September 2017 (UTC)

I have adopted the alternative suggestion, and updated the main article page accordingy. Shelldozer (talk) 14:32, 19 September 2017 (UTC)