Thanks Theo. I will get the version 8 manual. Is the title for that "Armv8-m
Archetecture Reference Manual"? From what you've said, I was probably looking
at the v8-A manual.

Hul

Theo <theom+news@chiark.greenend.org.uk> wrote:
> Hul Tytus <ht@panix.com> wrote:
> > I'm aiming at the 32 bit devices and looking at the v7 text.

> ARMv8-M devices /are/ 32 bit.

> ARMv8-A brought in the 64 bit instruction set (AArch64) for Application
> cores.  The classic 32 bit instruction set (AArch32) remains optional for
> Application cores.  v8-A (and v9-A) describe the Application class
> architecture.

> ARMv8-M describes the Microcontroller class architecture and it's all 32
> bit.  For example v8-M brought in TrustZone instructions which weren't in
> ARMv7-M.

> You should check which core(s) you plan to use and what architecture they
> are.  For example the Cortex M55 follows ARMv8.1-M while the Cortex M7
> follows ARMv7E-M.

> Theo

Hul Tytus <ht@panix.com> wrote:
> I'm aiming at the 32 bit devices and looking at the v7 text.

ARMv8-M devices /are/ 32 bit.

ARMv8-A brought in the 64 bit instruction set (AArch64) for Application
cores.  The classic 32 bit instruction set (AArch32) remains optional for
Application cores.  v8-A (and v9-A) describe the Application class
architecture.

ARMv8-M describes the Microcontroller class architecture and it's all 32
bit.  For example v8-M brought in TrustZone instructions which weren't in
ARMv7-M.

You should check which core(s) you plan to use and what architecture they
are.  For example the Cortex M55 follows ARMv8.1-M while the Cortex M7
follows ARMv7E-M.

Theo

Apparantly you read a different version of the GNU copyright
than I did but I didn't read it all. It does vary with
time.

Hul

Tauno Voipio <tauno.voipio@notused.fi.invalid> wrote:
> Your code is just data passed through the tools, the GNU
> copyright does not limit it.

> You'll be safe as long as you are not going to modify the
> tools. Even then you have to publish the modifications, not
> the code processed using the tools.

> For libraries, there is the GNU LGPL coversin such cases
> and permitting to use them.

> -- 

> -TV


> On 17.4.2021 22:38 PM, Hul Tytus wrote:
> > Tauno - just the GNU copyright provides reason for not using it.
> > I would expect anyone using it, or considering same, to a major extent, whether
> > government sponsored or private, would look closely.
> > 
> > Hul
> > 
> > Tauno Voipio <tauno.voipio@notused.fi.invalid> wrote:
> >> On 17.4.21 18.53, Hul Tytus wrote:
> >>> David - I'm in the process of putting together an assembler for the Arm
> >>> 32 bit processors. There is no all-knowing compiler envolved so I need
> >>> to know what machine codes are valid for a given processor. Any suggestions
> >>> on where that information can be found?
> > 
> > 
> >> Why on earth?
> > 
> >> What is wrong with the GNU arm-none-eabi-as?
> > 
> >> The arm-none-eabi-gcc has switches for different processor
> >> architectures.
> > 
> >> ARM has an instruction reference card for Thumb2, with
> >> different processors marked on the card.
> > 
> >> -- 
> > 
> >> -TV

Maybe I should take a look at the version 8 text. Thanks

Hul

antispam@math.uni.wroc.pl wrote:
> Hul Tytus <ht@panix.com> wrote:
> > David - I'm in the process of putting together an assembler for the Arm
> > 32 bit processors. There is no all-knowing compiler envolved so I need
> > to know what machine codes are valid for a given processor. Any suggestions
> > on where that information can be found?

> If you think about microcontrollers, then most relevant probably
> is ARM v8-M Architecture Reference Manual which I found under
> file name DDI0553A_e_armv8m_arm.pdf

> It contains list of instructions with their encodings. v8 is resonably
> recent (maybe newest) version of ARM architecture.  Since ARM is
> mostly adding instructions it probably covers all intructions that
> you want to support.  ARM defined several subsets, for example
> Cortex -M3 Devices Generic User Guide file name
> DUI0552A_cortex_m3_dgug.pdf describes Cortex M3, in particular
> provides list of valid instructions.

> Collectiong information that you need looks like large and tedious
> job: you need to check instruction descriptions to know if
> instruction is valid for given subset (given mnemonic may be
> valid, but specific combination of argument may be invalid).
> I am not aware any documents containing needed data is
> syntetic form.  You may try a shortcut: generate "program"
> that contains all varianants of all instructions and look
> which one GNU assembler accepts for given subset (model).
> Of course, in this way you will repeat any bugs in tables
> in GNU assembler.  OTOH tables in GNU assembler are probably
> debugged at least as well as ARM documents...

> -- 
>                               Waldek Hebisch

I'm aiming at the 32 bit devices and looking at the v7 text.

Hul

Theo <theom+news@chiark.greenend.org.uk> wrote:
> Hul Tytus <ht@panix.com> wrote:
> > Thanks again Richard. I will assume that the "Arm v7-m Architecture Reference
> > Manual" is most current. The only similiarly titled text on Arm's web site
> > was for a 64 bit version. 

> You probably want the ARMv8-M architecture reference, unless you're dealing
> with older hardware:
> https://developer.arm.com/documentation/ddi0553/latest

> THeo

(Please don't top-post - it is making a serious mess of this thread.
I've fixed it here.)

On 17/04/2021 21:38, Hul Tytus wrote:
> 
> Tauno Voipio <tauno.voipio@notused.fi.invalid> wrote:
>> On 17.4.21 18.53, Hul Tytus wrote:
>>> David - I'm in the process of putting together an assembler for the Arm
>>> 32 bit processors. There is no all-knowing compiler envolved so I need
>>> to know what machine codes are valid for a given processor. Any suggestions
>>> on where that information can be found?
> 
> 
>> Why on earth?
> 
>> What is wrong with the GNU arm-none-eabi-as?
> 
>> The arm-none-eabi-gcc has switches for different processor
>> architectures.
> 
>> ARM has an instruction reference card for Thumb2, with
>> different processors marked on the card.
> 
> Tauno - just the GNU copyright provides reason for not using it.
> I would expect anyone using it, or considering same, to a major
extent, whether
> government sponsored or private, would look closely.
>
> Hul

The copyright ownership has no particular relevance here, it is the
license that is important.  And the license lets you use the tools
completely freely for any purpose - commercial, governmental, private,
or whatever.  It only places restrictions on what you can do with the
source code to the assembler - you can modify it that source as much as
you like, but if you give people a copy of a binary version of the
assembler, you need to give them a copy of the modified source too.  The
GPL does not affect your ARM code in any way.

The GNU toolchain - assembler, linker, compiler collection - are far and
away the most used development toolchain in the world, and cover the
widest range of targets.  If the copyright or license caused some
restriction in how they could be used or who could use them, someone
would have noticed by now.

And if you want to be able to take the source code for an ARM assembler,
modify it, and pass on (or sell) the binaries while keeping your changes
secret, then you could look to the LLVM project which also includes an
assembler and supports ARM as a target, and is all under a BSD/MIT style
license.

(Please don't top-post.  Usenet has its standards for formatting posts,
and it is best to stick to those.)

On 17/04/2021 21:30, Hul Tytus wrote:
> David: writing an assembler isn't really a "big effort" although
> the documentation of the Arm and the heaps of machine codes it
> has moves in that direction. As for "why?", there are several
> reasons and fun is one.
>    Thanks for the direction regarding the Arm device.
> 
> Hul

I have always felt that "fun" is a perfectly good reason for any
programming project - you don't need more than that.  But there is no
doubt that as assemblers go, making one for ARM is complicated by all
its variations and the fact that unlike most assemblies, there is not a
one-to-one relationship between assembly instructions and machine code
instructions.

But have fun with it anyway!

Your code is just data passed through the tools, the GNU
copyright does not limit it.

You'll be safe as long as you are not going to modify the
tools. Even then you have to publish the modifications, not
the code processed using the tools.

For libraries, there is the GNU LGPL coversin such cases
and permitting to use them.

-- 

-TV


On 17.4.2021 22:38 PM, Hul Tytus wrote:
> Tauno - just the GNU copyright provides reason for not using it.
> I would expect anyone using it, or considering same, to a major extent, whether
> government sponsored or private, would look closely.
> 
> Hul
> 
> Tauno Voipio <tauno.voipio@notused.fi.invalid> wrote:
>> On 17.4.21 18.53, Hul Tytus wrote:
>>> David - I'm in the process of putting together an assembler for the Arm
>>> 32 bit processors. There is no all-knowing compiler envolved so I need
>>> to know what machine codes are valid for a given processor. Any suggestions
>>> on where that information can be found?
> 
> 
>> Why on earth?
> 
>> What is wrong with the GNU arm-none-eabi-as?
> 
>> The arm-none-eabi-gcc has switches for different processor
>> architectures.
> 
>> ARM has an instruction reference card for Thumb2, with
>> different processors marked on the card.
> 
>> -- 
> 
>> -TV

Hul Tytus <ht@panix.com> wrote:
> David - I'm in the process of putting together an assembler for the Arm
> 32 bit processors. There is no all-knowing compiler envolved so I need
> to know what machine codes are valid for a given processor. Any suggestions
> on where that information can be found?

If you think about microcontrollers, then most relevant probably
is ARM v8-M Architecture Reference Manual which I found under
file name DDI0553A_e_armv8m_arm.pdf

It contains list of instructions with their encodings. v8 is resonably
recent (maybe newest) version of ARM architecture.  Since ARM is
mostly adding instructions it probably covers all intructions that
you want to support.  ARM defined several subsets, for example
Cortex -M3 Devices Generic User Guide file name
DUI0552A_cortex_m3_dgug.pdf describes Cortex M3, in particular
provides list of valid instructions.

Collectiong information that you need looks like large and tedious
job: you need to check instruction descriptions to know if
instruction is valid for given subset (given mnemonic may be
valid, but specific combination of argument may be invalid).
I am not aware any documents containing needed data is
syntetic form.  You may try a shortcut: generate "program"
that contains all varianants of all instructions and look
which one GNU assembler accepts for given subset (model).
Of course, in this way you will repeat any bugs in tables
in GNU assembler.  OTOH tables in GNU assembler are probably
debugged at least as well as ARM documents...

-- 
                              Waldek Hebisch

Hul Tytus <ht@panix.com> wrote:
> Thanks again Richard. I will assume that the "Arm v7-m Architecture Reference
> Manual" is most current. The only similiarly titled text on Arm's web site
> was for a 64 bit version. 

You probably want the ARMv8-M architecture reference, unless you're dealing
with older hardware:
https://developer.arm.com/documentation/ddi0553/latest

THeo