[Info-vax] Three boot camp sessions on YouTube

[John Reagan]

On Wednesday, October 12, 2016 at 7:04:27 AM UTC-4, Neil Rieck wrote:
> On Tuesday, October 11, 2016 at 2:44:10 PM UTC-4, Simon Clubley wrote:
> > On 2016-10-07, Camiel Vanderhoeven <> wrote:
> > >
> > > Well, there are similarities and differences between x86 and all of
> > > the previous architectures:
> > >
> > > x86 is a lot like VAX when you look at its instruction set
> > 
> > Except of course (as you also pointed out in one of the videos)
> > the x86 has lots of special purpose registers unlike the VAX where
> > the registers are general purpose registers.
> > 
> > I've done x86 assembly language programming in the past. It wasn't
> > a pleasant experience, especially when compared to the likes of
> > ARM or even (to a lesser extent) MIPS.
> > 
> > BTW, I noticed on one of your graphs that you have MIPS marked as
> > EOL. Has MIPS development actually ceased now (because I'm still
> > seeing it around in various places) ?
> > 
> > Microchip still have the PIC32 range which are low end MIPS cores.
> > 
> > Simon.
> > 
> > -- 
> > Simon Clubley, clubley
> > Microsoft: Bringing you 1980s technology to a 21st century world
> 
> For me, the big difference between Alpha and Itanium in those videos was the register count (32 vs. 128).  Having 128 registers may have seemed like a good idea when they were designing that chip, but we all know that an OS is going to require some/all those registers to be periodically saved then restored (well, not all on every interrupt). I wonder if Intel would have implemented 128 had they known that dynamic memory technology would keep improving as it has. 
>  
> So with the shift back to x86, the maximum number of registers appears to be moving to a more manageable number.
>  
> Neil Rieck
> Waterloo, Ontario, Canada.
> http://www3.sympatico.ca/n.rieck/

And now the compilers have to put many more variables on the stack and do memory reads/writes all the time.  Yes, you had to save/restore some of the register stack on interrupts, mode changes, context swaps, etc. but if you count the memory operations saved from not keeping your variables on the stack, I think it might come out better.