I am also looking for an Alpha simulator. Problem with FreeAXP is that it won't run in Wine and I only have Linux. There used to be one called AlphaVM Free but now they charge a prohibitive cost for the hobbyist version.
On Nov 20, 2017 11:45 AM, "Eberhard Heuser" < eberhard.heu...@chemie.uni-konstanz.de> wrote: > Am 20.11.2017 um 17:36 schrieb Hittner, David T [US] (MS): > >> I'm actually working on the Alpha implementation right now, during my >> not-as-free-as-I-would-like time. >> >> Why is it taking so long? >> ------------------------------- >> The Alpha is amazingly complex, as you have to simulate the entire set of >> PC devices (JDEC memory, RT Clock, APICs, Serial Ports, etc.) and buses >> (PCI, ISA, EISA, SCSI, USB, etc.) that have not been developed for SIMH >> yet. I have recently found almost all of the needed PC device simulation >> logic in the QEMU code base, and might be able to port that logic into the >> SIMH simulator to speed up the development process. Driving the SCSI bus >> state transitions will be particularly time consuming without the real >> dedicated SCSI processors which were on every SCSI device and host card. >> >> I have the Alpha simulator booting and running some 68 million >> instructions before it gives up due to a "fatal hardware error", but it >> hasn't gotten up to the firmware chevrons (>>>) yet, as I haven't simulated >> most of the required hardware devices yet. The Alpha Firmware itself is a >> very complex OS, initializing and testing the hardware, and setting up all >> of the in-memory data structure required by the Alpha Architecture manual, >> before running the interactive console chevron dialog. >> >> What about JIT? >> -------------------- >> The emulator is also amazingly slow compared to real hardware due to the >> sheer number of emulated instructions executed and the emulation overhead. >> JIT would be a wonderful thing, but it's more important to get the >> emulation right than to make it work faster, as (theoretically) newer host >> hardware will eventually "catch up" to the emulation overhead. That said, >> the TCG (Tiny Code Generator) component of QEMU has made me think that we >> could "do some JIT" in SIMH, either at the single instruction level or at >> the block level. The primary impact of adding JIT to the emulator is that >> it throws the emulated clock off - SIMH time, IO, and polling works by >> counting emulated instructions, and if the emulation instruction count >> "jumps" because you executed a large block of JIT code, it could >> significantly delay or miss the response required for SIMH polling and >> simulated clock interrupts. It is unlikely that a SIMH Alpha emulation will >> ever hit the speeds of the commercial emulators, since SIMH is designed be >> portable, and the commercial emulators are tweaked for specific host >> platforms. Note that SIMH VAX has never hit the speeds posted by commercial >> VAX emulators, but runs on almost anything. It is probable that JIT would >> only be possible on specific host processors or host OS's, requiring that >> the emulator be capable of both JIT and non-JIT operation. >> >> >> If anyone would care to help in the Alpha development process, I can >> start checking my code in to allow other developers to assist. If you are >> interested in helping, send me an email. >> >> In the meantime, if you just want to run a free Alpha emulator, the >> FreeAXP emulator from MSI is and will continue to be available. >> >> David Hittner >> >> -----Original Message----- >> From: Simh [mailto:simh-boun...@trailing-edge.com] On Behalf Of Paul >> Koning >> Sent: Monday, November 20, 2017 8:58 AM >> To: Gordon Miller <gordonamille...@gmail.com> >> Cc: simh@trailing-edge.com >> Subject: EXT :Re: [Simh] Any chance of AXP for SIMH ? >> >> >> >> On Nov 20, 2017, at 12:07 AM, Gordon Miller <gordonamille...@gmail.com> >>> wrote: >>> >>> Hi guys >>> >>> I'm the new kid here, despite my grey hair. >>> >>> Anyway, what I'm quite interested in, is any kind of Alpha AXP support >>> for SIMH. >>> >> Take a look at the current code, there is an "alpha" subdirectory. I >> don't remember the status of that, probably quite preliminary but there are >> at least some pieces in place. >> >> paul >> >> >> _______________________________________________ >> Simh mailing list >> Simh@trailing-edge.com >> http://mailman.trailing-edge.com/mailman/listinfo/simh >> _______________________________________________ >> Simh mailing list >> Simh@trailing-edge.com >> http://mailman.trailing-edge.com/mailman/listinfo/simh >> > > Take a look into the es40 source code: > > https://sourceforge.net/projects/es40 > > eberhard > > > > --- > Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft. > https://www.avast.com/antivirus > > _______________________________________________ > Simh mailing list > Simh@trailing-edge.com > http://mailman.trailing-edge.com/mailman/listinfo/simh
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