Arm registers

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

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

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

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