[Info-vax] Moving WASD from one box to another...

[John Reagan]

"Mark Daniel" <mark.daniel at vsm.com.au> wrote in message 
news:0174f553$0$20652$c3e8da3 at news.astraweb.com...
> Jan-Erik Söderholm wrote:
>
>> The CC compiler has the same writing in the HELP texts, so I guess
>> this emulation of higher-EV-code is not tied to the compiler
>> itself.
>
> I sure others here can comment authoritatively on compiler construction.
>

/ARCH lets the compiler generate new instructions.  EV56 added the byte/word 
instructions.  They are emulated on pre-EV56 CPUs by the operating system. 
Instructions added after EV56 have little overall benefit for most 
applications.  It helps a few applications (mostly SPECmarks at the time) 
with SQRT and FTOI, but in general, not much for others.  [I'm not sure that 
the emulator does the right thing for such instructions on pre-EV6 systems. 
I've never tried it.]

/OPT=TUNE controls the instruction scheduling for a particular chip variant. 
Different schedulings will never produce the wrong answer, but might cause a 
cache miss or a stall.  I've seen folks play with /ARCH=EV56/OPT=TUNE=EV6 
and such, but again, only playing with SPECmarks.

Personally, I'd just say /ARCH=EV56 (which will make EV56 the default for 
/OPT=TUNE) and be done with it if you think you won't see many 
EV4/EV45/EV5s.

John Reagan