Re: modeling a simple cpu

From: Ara.T.Howard [mailto:[email protected]]

i need to model the on board cpu of a satellite in order to
mock running uploaded commands. basically i need to model
the internal state and all incoming commands so i can
determine register states at a given point in time.

Not to distract the thread from your very real question, but you do
realize that you have one of the coolest jobs around, right? :slight_smile:

On 10/26/06, Gavin K. [email protected] wrote:

From: Ara.T.Howard [mailto:[email protected]]

i need to model the on board cpu of a satellite in order to
mock running uploaded commands. basically i need to model
the internal state and all incoming commands so i can
determine register states at a given point in time.

Not to distract the thread from your very real question, but you do
realize that you have one of the coolest jobs around, right? :slight_smile:

Right, why should we help him hey?
Seriously Ara wasn’t there a Ruby Q. about it
http://rubyquiz.com/quiz88.html
(the only one I replied to BTW)?

HTH
Robert

–
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore all progress
depends on the unreasonable man.

  • George Bernard Shaw

On Oct 26, 2006, at 3:28 PM, Gavin K. wrote:

From: Ara.T.Howard [mailto:removed_ema[email protected]]

i need to model the on board cpu of a satellite in order to
mock running uploaded commands. basically i need to model
the internal state and all incoming commands so i can
determine register states at a given point in time.

Not to distract the thread from your very real question, but you do
realize that you have one of the coolest jobs around, right? :slight_smile:

I agree. :wink:

James Edward G. II

Gavin K. wrote:

From: Ara.T.Howard [mailto:[email protected]]

i need to model the on board cpu of a satellite in order to
mock running uploaded commands. basically i need to model
the internal state and all incoming commands so i can
determine register states at a given point in time.

Not to distract the thread from your very real question, but you do
realize that you have one of the coolest jobs around, right? :slight_smile:

The last processor I successfully modeled was the old 6502 (Apple II),
since
then processor behavior has become too difficult to sort out in any
reliable way (IMHO).

It would be interesting for the OP to reveal what kind of processor is
involved, and how complex. I am going to assume it doesn’t support
interrupts or threads, otherwise there is little chance to mimic its
behavior.

On Fri, 27 Oct 2006, Paul L. wrote:

The last processor I successfully modeled was the old 6502 (Apple II), since
then processor behavior has become too difficult to sort out in any
reliable way (IMHO).

It would be interesting for the OP to reveal what kind of processor is
involved, and how complex. I am going to assume it doesn’t support
interrupts or threads, otherwise there is little chance to mimic its
behavior.

it’s for these guys

http://heasarc.nasa.gov/docs/heasarc/missions/dmsp.html
http://www.ngdc.noaa.gov/dmsp/

at this point i only need to model a limited subset of the processor (i
don’t
know the type yet). basically i’ll be executing something long these
lines

 !=================================================================
 !*****  GAIN ORBIT MEMORY FOR OPS45  26 JAN 04 - 01 FEB 04   *****
 !=================================================================
 !
  0.000  CMD  OAXSPG   0x00       ; 807E#  (PAGE=0)
  0.000  CMD  OGNASG   LIN        ; 0010#  ASGC LIN
 !
  0.076  CMD  OAXLOD   0xA2       ; 511E#  (112dB) (SED)
  0.076  CMD  OAXSTR   0x44       ; A22E#  (BC MAX)
 !
  0.316  CMD  OAXLOD   0x03       ; 819E#  (.08) (VED-1/00)
  0.316  CMD  OAXSTR   0x48       ; A42E#  (BRDF X2)
 !
  0.324  CMD  OAXLOD   0x06       ; 831E#  (.25) (VED-00/12)
  0.324  CMD  OAXSTR   0x46       ; 232E#  (BRDF HRD)
  0.324  CMD  OAXLOD   0x9E       ; 4F1E#  (136dB)
  0.324  CMD  OAXSTR   0x44       ; A22E#  (BC MAX)
 !
  0.326  CMD  OAXLOD   0x8E       ; C71E#  (118dB) (VES)
  0.326  CMD  OAXSTR   0x44       ; A22E#  (BC MAX)
 !
  0.650  CMD  OAXLOD   0x29       ; 149E#  (.02)
  0.650  CMD  OAXSTR   0x48       ; A42E#  (BRDF X2)

 ....
 ....
 ....

as you can tell these are load/store/add instuctions. there are no
parameters, all the values are burned on board before flight - so there
are
only certain values you can do ops with. as you can tell it’s ultra
simple -
basically i’ll just have to model rom, ram, registes, and ops.

hey - a smell a ruby quiz! :wink:

-a

On Fri, 27 Oct 2006, Robert D. wrote:

Right, why should we help him hey?
Seriously Ara wasn’t there a Ruby Q. about it
http://rubyquiz.com/quiz88.html
(the only one I replied to BTW)?

HTH
Robert

great resource! thanks!

-a

[email protected] wrote:

Not to distract the thread from your very real question, but you do
behavior.

!
!

simple -
basically i’ll just have to model rom, ram, registes, and ops.

hey - a smell a ruby quiz! :wink:

-a

Isn’t there an open-source “universal old architecture emulator” package
of some kind? I remember seeing it in Debian when I was running Debian
– it could play most of the old Atari games, etc.

I can certainly see if it’s in Gentoo, if I can figure out what it was
called.

M. Edward (Ed) Borasky wrote:

Isn’t there an open-source “universal old architecture emulator” package
of some kind? I remember seeing it in Debian when I was running Debian
– it could play most of the old Atari games, etc.

I can certainly see if it’s in Gentoo, if I can figure out what it was
called.

I think I found it … simh

http://simh.trailing-edge.com/

Of course, I’m probably the only one on this list that’s actually
touched some of those gizmos :slight_smile:

Sheesh – a computer museum on your hard drive :slight_smile:

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