P
Peter Dickerson
- Jan 1, 1970
- 0
krw said:Of course there are examples of hardwired CISC machined (360/75).
That wasn't the point.
Is it called by a JSR instruction?
Petty much. More like a system call.
Peter
krw said:Of course there are examples of hardwired CISC machined (360/75).
That wasn't the point.
Is it called by a JSR instruction?
Nick Maclaren said:|> |>
|> >> PAL-code isn't microcode because it's essentially the same
instruction
|> >> set, processed through the same decoders and schedulers as the
externally
|> >> visible instruction set. It's a subroutine library.
|> >
|> > Is it called by a JSR instruction?
|>
|> Petty much. More like a system call.
I think that you meant "Not really"! It changes to kernel context
(well, roughly).
There were systems that had the equivalent that was more like a
subroutine - the Ferranti Atlas/Titan extracodes were done like that.
There are MASSIVE advantages to such a mechanism, because it can be
used to provide complex instruction emulation efficiently and
transparently without any of the scheduling or RAS problems that
come in if you have iffy PALcode.
Petty much. More like a system call.
Well, my very old Alpha architecture book calls the instruction CALL_PAL,
which has a 6-bit opcode (0) and 26 function code bits (what I might call an
abstract target address). The expectation from the opcode name is that after
it does whatever it does it will return to the instruction following the
CALL_PAL instruction. JSR, presumably jump-to-subroutine, is much the same.
The differences are in how the target address is determined and some state.
But then I'd say an INTn instruction on x86 is like a call too...
Nick Maclaren said:|>
|> Well, my very old Alpha architecture book calls the instruction CALL_PAL,
|> which has a 6-bit opcode (0) and 26 function code bits (what I might call
an
|> abstract target address). The expectation from the opcode name is that
after
|> it does whatever it does it will return to the instruction following the
|> CALL_PAL instruction. JSR, presumably jump-to-subroutine, is much the same.
|> The differences are in how the target address is determined and some state.
|> But then I'd say an INTn instruction on x86 is like a call too...
Grrk. And so would most SVCs be on System/370. But that is ONLY in
control flow, for the non-exceptional case. PALcode is documented
to change the environment, which is entirely unlike a subroutine
call on modern systems. Oh, yes, you could change addressing mode
on System/370, but full context changes at a subroutine call are
very different.
Yes, PALcode is USED like a subroutine, but that isn't how it works.
Regards,
Nick Maclaren.
Where has Radium gone? Haven't seen any of his dribble in a few days. Maybe
the idiocy of his notion finally sunk in??
LOL, I'm still here and dreaming of a PC that has the advantages of
the world's current best PC along with additional advantages. For
example, my dream PC is entirely chip-based and does *not* require any
of the following:
1. Fans or other cooling equipment
2. Moving parts
3. Magnetic parts
4. Discs
5. ROM
In addition, my dream PC does not experience any latency or use any
buffering at all.
Radium said:1. Fans or other cooling equipment
2. Moving parts
3. Magnetic parts
4. Discs
5. ROM
In addition, my dream PC does not experience any latency or use any
buffering at all.
LOL, I'm still here and dreaming of a PC that has the advantages of
the world's current best PC along with additional advantages. For
example, my dream PC is entirely chip-based and does *not* require any
of the following:
1. Fans or other cooling equipment
2. Moving parts
3. Magnetic parts
4. Discs
5. ROM
In addition, my dream PC does not experience any latency or use any
buffering at all.
Add to that wish list:
Peace for the peoples
Bread for the hungry
Land for the farmers
Factories for the workers
LOL
We already do this.LOL, I'm still here and dreaming of a PC that has the advantages of
the world's current best PC along with additional advantages. For
example, my dream PC is entirely chip-based and does *not* require any
of the following:
1. Fans or other cooling equipment
We can do this too.2. Moving parts
Why would you care if it is magnetic? Non-linear magneto-optical3. Magnetic parts
4. Discs
5. ROM
No problem! Just kill all of the politicians! ;-)
Cheers!
Rich
We already do this.
We can do this too.
Why would you care if it is magnetic? Non-linear magneto-optical
effects could allow very fast logic at extremely low power levels.
We already do this.
Why no ROM. It is very handy stuff.
Eventually the signal has to become electric for processing. Why waste
time converting signals from electric to magnetic [and visa versa]?
LOL, I'm still here and dreaming of a PC that has the advantages of
the world's current best PC along with additional advantages. For
example, my dream PC is entirely chip-based and does *not* require any
of the following:
1. Fans or other cooling equipment
2. Moving parts
3. Magnetic parts
4. Discs
5. ROM
In addition, my dream PC does not experience any latency or use any
buffering at all.
Why would you care if it is magnetic? Non-linear magneto-optical
effects could allow very fast logic at extremely low power levels.
Eventually the signal has to become electric for processing. Why waste
time converting signals from electric to magnetic [and visa versa]?
Because I prefer that the info usually stored in ROM, be generated in
real-time.
The following is a bad analogy but I'll add it anyway.
PC reading info from ROM = sample playback synth playing back its
samples of sounds of an FM synth.
PC chip generating its signals in real-time = an *actual* FM synth
freshly-generating its tones "on the fly".
Yes, I know, the above is a poor analogy but I couldn't think of
anything better.
Eventually the signal has to become electric for processing. Why waste
time converting signals from electric to magnetic [and visa versa]?
No problem, just use electromagnetic devices for everything. No tedious
conversions necessary.
MooseFET said:He said he is Aspergered. This will mean that he may have some
trouble really understanding your suggestion and its intended
purpose. It doesn't prevent him from learning electronics but he will
have to develop his own was of dealing with things. It is likely that
he will work in terms of images in places you would work with
equations.