[Simh] Is Alpha AXP in SIMH's future?

[Mark Pizzolato - Info Comm]

On Tuesday, March 3, 2015 at 12:44 PM, Serge Oboguev wrote:
> The downside of running a 32-bit version of virtually any AXP simulator is
> that it is bound to be 2-3 times slower than 64-bit version, due to
> 
> (a) simulation of AXP 64-bit operations on top of 32-bit host operations,
> 
> (b) indirect access to guest memory when it is sized above 2 GB or so
>     assuming such an access is implemented at all.
> 
> The only exception to (a) would be a 64-bit simulator squeezed into 32-bit
> environment running on 64-bit machine, but this is hardly worth the effort.

How did this get to be a discussion about running a 32bit simulator of a 64bit machine?

The ONLY requirement that the simh framework would require to implement a AXP simulator would be that the host machine have 64bit integer support.  Certainly if large memory was to be simulated (as would only be reasonable with an AXP simulator) then things would have to run on an 64bit capable host with a 64bit OS compiled as a 64bit binary.

The existing makefile will compile simulators with the default compiler available on the host (gcc) or any other compiler which is explicitly requested by GCC=othercompiler on the make command line.  If the host system is native 64bit and the compiler is native 64bit then the resulting simulator will be fully capable of providing memory beyond 4GB.  Nothing special needs to be done.

There already are other simulators which require 64bit integer support.  

- Mark


> ----- Original Message -----
> From: "lists at openmailbox.org" <lists at openmailbox.org>
> To: "Simh at trailing-edge.com" <Simh at trailing-edge.com>
> Cc:
> Sent: Tuesday, March 3, 2015 9:25 AM
> Subject: [Simh] Is Alpha AXP in SIMH's future?
> 
> Is an Alpha machine capable of running OpenVMS in SIMH's future? I know
> there are several Alpha emulators for Linux and Windows but I really like
> SIMH since it runs on pretty much any UNIX-like OS and doesn't depend on
> having a 64-bit Linux installed.
> 
> Thank you for SIMH.
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