Re: [Simh] retargetable assembler

[Phil Budne]

Please disregard dead.letter detritus!

> > How do you feel about the dwelling value?  The inspection came in at 
> > $133,000 for the replacement cost of your home, do you agree? The policy is 
> > currently at $205,000.
>
> How was the inspection estimate calculated:
> Was it based on current condition or replacement cost?


A message I killed, when I realized I had quoted the answer
to the question I was asking!
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Re: [Simh] retargetable assembler

[Phil Budne]

> How do you feel about the dwelling value?  The inspection came in at $133,000 
> for the replacement cost of your home, do you agree? The policy is currently 
> at $205,000.

How was the inspection estimate calculated:
Was it based on current condition or replacement cost?

> Reading the Wikipedia page about Whirlwind, it mentions that the pdp1 is a 
> direct descendent, so would a pdp1 assembler work? Or a tx0 Assembler? I 
> don't know if these already exist or not.

There's certainly close interrelation the the development of Whirlwind, TX-0 
and the PDP-1.

http://libraries.mit.edu/archives/research/collections/collections-mc/mc665.html
says:

The U.S. Air Force provided substantial financial support for
Whirlwind applications and it was a key component in the
design of the Air Force's SAGE (Semi-Automatic Ground
Environment) air defense system in the 1950s. Research
projects at Lincoln Laboratory resulted in the further
development of two additional computers, the MTC (memory test
computer) and TX-0 (transistor computer), by Group 63 of
Lincoln Lab, Division 6.

http://americanhistory.si.edu/comphist/olsen.html

Ken Olsen:

We understood from experience that you really had to test
every possible combination. Because [no matter] how thoroughly
you designed things there's always something that might go
wrong or some combination of things that might be wrong. And
people were not about to trust the core memory unless it was
truly tested in an environment that was tested. So we set
about to build what we called a memory test computer. It was
supposed to be an honest to goodness computer that would
really run and test the memory, but not a computer that
designed to be useful. I was given the job of building the
computer just as soon as my thesis was done. I think I was
still a graduate student and it cost a million dollars. I can
remember being impressed of how much a million dollars
was. How much work it took to spend a million dollars. Now I'm
impressed at how little effort it takes to spend a million
dollars. So we built a 16-bit machine.



[STANDING AT THE TX-0 COMPUTER] When I was given the
opportunity to work on a transistor computer, the idea was
kind of new, it was exciting and we had knowledge of the very
fast transistor which we had built a very fast computer. The
rules were, I could hire nobody and have no space. I studied
the rules carefully and found all the loopholes. I somehow was
able, one way or another, to get three or four people to work
with me. We discovered that hallway was not space. So we moved
my office into the hall and put walls around it. We then
traded that space for a space in the basement which was less
desirable but bigger. With that we were able to do our work.

TX-0 was to TX-2 as MTC was to the Whirlwind.

The PDP-1 was designed by Ben Gurley, who had worked on TX-0 and TX-2.

http://www.computerhistory.org/pdp-1/ben-gurley/

Two years after DEC was formed in 1957, Ben Gurley was brought
on board to work on the PDP-1 with fellow engineers--and former
Lincoln Laboratory employees--Ken Olsen, Dick Best, Bob Savell,
Harlan Anderson, and Stan Olsen. Their computer design work at
MIT greatly influenced the development of the PDP-1, which has
been described as a "direct descendant" of the TX-0 and TX-2
computers created at MIT.

You can find a PDP-1 cross-assembler at
https://github.com/simh/simtools/tree/master/crossassemblers/macro1/

I wacked at it to be PDP-1 MACRO compatible enough to assemble MACRO sources.

It has PDP-1 opcode values built in (unlike the actual implementations
back in the day, where the opcodes were defined by a source (paper)
tape.  The same is the case with the "as" assembled on PDP-7 UNIX,
which I also coaxed back to life), nonetheless it should suffice!

ISTR:
the MACRO (and MIDAS?) assemblers got their start on TX-0.
one of them was translated to the PDP-1 in a weekend hack attack (on a 
bet?)
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Re: [Simh] retargetable assembler

[Al Kossow]

On 9/6/17 11:26 AM, khandy21yo wrote:

> Is there any source for actual Whirlwind Code?
CHM has paper and magnetic tapes archived, but not read.
Code appears in various docments on bitsavers

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Re: [Simh] retargetable assembler

[khandy21yo]

Wikipedia has some rather odd ideas sometimes.
Is there any source for actual Whirlwind Code? It might give more information 
about how people actually used it. 

Sent from my Galaxy Tab® A
 Original message From: Paul Koning <paulkon...@comcast.net> 
Date: 9/6/17  8:19 AM  (GMT-07:00) To: khandy21yo <khandy2...@gmail.com> Cc: 
Timothe Litt <l...@ieee.org>, simh@trailing-edge.com Subject: Re: [Simh] 
retargetable assembler 

> On Sep 6, 2017, at 9:21 AM, khandy21yo <khandy2...@gmail.com> wrote:
> 
> Reading the Wikipedia page about Whirlwind, it mentions that the pdp1 is a 
> direct descendent, so would a pdp1 assembler work? Or a tx0 Assembler? I 
> don't know if these already exist or not.

I wonder why it would say that.  PDP1 and TX0 are both 18-bit machines.  Their 
instruction sets are quite different from each other, and very different also 
from Whirlwind judging by the documents on Bitsavers.  They are all single 
address accumulator machines, but then again so are most other computers of 
that era.

paul

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Re: [Simh] retargetable assembler

[Timothe Litt]

On 06-Sep-17 08:19, Paul Koning wrote:
>> On Sep 5, 2017, at 9:18 PM, Timothe Litt  wrote:
>>
>> It's a heavy lift & overkill, but GCC (gas) can be made to cross-compile 
>> for/from any reasonable machine.  That gives you a complete toolset - but 
>> it's a lot of work.
> The assembler (gas) is separate from the compiler (gcc and friends).  It's a 
> prerequisite for a complete cross-package but you can certainly do a gas for 
> some new architecture without bothering with the compiler.
gdb gives you a disassembler.
> The question is assembler syntax.  If the machine you're after has a standard 
> syntax, then gas is unlikely to help since it uses Unix "as" style syntax.  
> For example, while you can assemble PDP11 programs with gas, they don't look 
> like familiar Macro-11 programs and if you feed it Macro-11 sources it will 
> complain bitterly.
Yes, but presumably this is a bootstrapping exercise - hopefully the
native assembler can be found and used once the simulator runs.

As noted, this isn't the approach I'd take, but tastes (and energy
levels) vary.
>> If it were my project, I'd define some macros in MACRO-11 to create a 
>> cross-assembler, as IIRC Whirlwind has 16 bit wordsize.  MACRO-11 has a 
>> reasonable set of operators and macro pseudo-ops.  Define the Whirlwind 
>> instructions as macros, and you're all set.  People have done this for early 
>> micros - it's not quite native and can be a bit awkward - but it works and 
>> can be put together with minimal effort.  
>>
>> You can output absolute binary from the assembler - or link/task build if 
>> you want psects or libraries.  But with the small memory size, MACRO will do.
>>
>> If you want 32-bit words, there's always MACRO-32 - pretty much the same 
>> macro capabilities.
>>
>> For a host, you can use a simh PDP-11 or VAX - whatever you're comfortable 
>> with.
> Sure, those are good options.  Others mentioned Python to write one from 
> scratch.  That is very easy.  I've written an Electrologica assembler in 
> Python, which didn't take long, and a more limited assembler is probably just 
> a week or two worth of work.
>
> One complication for using Macro-11 is that Whirlwind is one-s complement, so 
> negative numbers will be wrong.
That can be handled with a macro to convert 2's complement to 1's,
including any end-around carry.

>   paul
>
>



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Re: [Simh] retargetable assembler

[Timothe Litt]

On 06-Sep-17 09:21, khandy21yo wrote:
> Reading the Wikipedia page about Whirlwind, it mentions that the pdp1
> is a direct descendent, so would a pdp1 assembler work? Or a tx0
> Assembler? I don't know if these already exist or not.
>
> Is the pdp1 a transistorized Whirlwind as the Wikipedia article
> suggests? We already have an emulator for that.
>
> Anyway, I remember reading about the tx0, and that they were always
> modifying the instruction set in hardware. For this early machine, was
> there even an official assembler Format? And which character sets did
> it use, probably not ascii.
>
ASCII didn't exist in the whirlwind timeframe; not until mid 1960s. 
IIRC, TX0 used a 5 level code from the Frieden flexowriter.  Probably
similar to Baudot.  Don't know about whirlwind.

yes, the architecture of early machines was fluid...





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Re: [Simh] retargetable assembler

[khandy21yo]

Reading the Wikipedia page about Whirlwind, it mentions that the pdp1 is a 
direct descendent, so would a pdp1 assembler work? Or a tx0 Assembler? I don't 
know if these already exist or not.
Is the pdp1 a transistorized Whirlwind as the Wikipedia article suggests? We 
already have an emulator for that.
Anyway, I remember reading about the tx0, and that they were always modifying 
the instruction set in hardware. For this early machine, was there even an 
official assembler Format? And which character sets did it use, probably not 
ascii.


Sent from my Galaxy Tab® A
 Original message From: Paul Koning <paulkon...@comcast.net> 
Date: 9/6/17  6:19 AM  (GMT-07:00) To: Timothe Litt <l...@ieee.org> Cc: 
simh@trailing-edge.com Subject: Re: [Simh] retargetable assembler 

> On Sep 5, 2017, at 9:18 PM, Timothe Litt <l...@ieee.org> wrote:
> 
> It's a heavy lift & overkill, but GCC (gas) can be made to cross-compile 
> for/from any reasonable machine.  That gives you a complete toolset - but 
> it's a lot of work.

The assembler (gas) is separate from the compiler (gcc and friends).  It's a 
prerequisite for a complete cross-package but you can certainly do a gas for 
some new architecture without bothering with the compiler.

The question is assembler syntax.  If the machine you're after has a standard 
syntax, then gas is unlikely to help since it uses Unix "as" style syntax.  For 
example, while you can assemble PDP11 programs with gas, they don't look like 
familiar Macro-11 programs and if you feed it Macro-11 sources it will complain 
bitterly.

> If it were my project, I'd define some macros in MACRO-11 to create a 
> cross-assembler, as IIRC Whirlwind has 16 bit wordsize.  MACRO-11 has a 
> reasonable set of operators and macro pseudo-ops.  Define the Whirlwind 
> instructions as macros, and you're all set.  People have done this for early 
> micros - it's not quite native and can be a bit awkward - but it works and 
> can be put together with minimal effort.  
> 
> You can output absolute binary from the assembler - or link/task build if you 
> want psects or libraries.  But with the small memory size, MACRO will do.
> 
> If you want 32-bit words, there's always MACRO-32 - pretty much the same 
> macro capabilities.
> 
> For a host, you can use a simh PDP-11 or VAX - whatever you're comfortable 
> with.

Sure, those are good options.  Others mentioned Python to write one from 
scratch.  That is very easy.  I've written an Electrologica assembler in 
Python, which didn't take long, and a more limited assembler is probably just a 
week or two worth of work.

One complication for using Macro-11 is that Whirlwind is one-s complement, so 
negative numbers will be wrong.

paul


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Re: [Simh] retargetable assembler

[Paul Koning]

> On Sep 5, 2017, at 9:18 PM, Timothe Litt  wrote:
> 
> It's a heavy lift & overkill, but GCC (gas) can be made to cross-compile 
> for/from any reasonable machine.  That gives you a complete toolset - but 
> it's a lot of work.

The assembler (gas) is separate from the compiler (gcc and friends).  It's a 
prerequisite for a complete cross-package but you can certainly do a gas for 
some new architecture without bothering with the compiler.

The question is assembler syntax.  If the machine you're after has a standard 
syntax, then gas is unlikely to help since it uses Unix "as" style syntax.  For 
example, while you can assemble PDP11 programs with gas, they don't look like 
familiar Macro-11 programs and if you feed it Macro-11 sources it will complain 
bitterly.

> If it were my project, I'd define some macros in MACRO-11 to create a 
> cross-assembler, as IIRC Whirlwind has 16 bit wordsize.  MACRO-11 has a 
> reasonable set of operators and macro pseudo-ops.  Define the Whirlwind 
> instructions as macros, and you're all set.  People have done this for early 
> micros - it's not quite native and can be a bit awkward - but it works and 
> can be put together with minimal effort.  
> 
> You can output absolute binary from the assembler - or link/task build if you 
> want psects or libraries.  But with the small memory size, MACRO will do.
> 
> If you want 32-bit words, there's always MACRO-32 - pretty much the same 
> macro capabilities.
> 
> For a host, you can use a simh PDP-11 or VAX - whatever you're comfortable 
> with.

Sure, those are good options.  Others mentioned Python to write one from 
scratch.  That is very easy.  I've written an Electrologica assembler in 
Python, which didn't take long, and a more limited assembler is probably just a 
week or two worth of work.

One complication for using Macro-11 is that Whirlwind is one-s complement, so 
negative numbers will be wrong.

paul


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