public inbox for
 help / color / mirror / Atom feed
From: Richard Earnshaw <>
To: Umesh Kalappa <>
Cc:, Binutils <>
Subject: Re: ARMV7a: selected processor does not support requested special purpose register
Date: Tue, 4 Oct 2022 11:03:27 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 04/10/2022 05:26, Umesh Kalappa wrote:
> Thank you Richard for the information and do you please point us to
> the reference ,which states the same ?
> Quick grep doesn't helped us ,Thank you again
> ~Umesh
> On Mon, Oct 3, 2022 at 9:24 PM Richard Earnshaw
> <> wrote:
>> On 03/10/2022 16:48, Richard Earnshaw via Binutils wrote:
>>> On 03/10/2022 15:41, Umesh Kalappa via Binutils wrote:
>>>> Hi All,
>>>> We have problem to compile the following asm
>>>> and asm error out with the subject message .
>>>> Is mrs for float special register not valid on cortex-a9 ?
>>>> Thank you
>>>> ~Umesh
>>> that's because the instruction you want is
>>> vmrs r4, fpscr
>>> R.
>> Also note that the fmrrs mnemonic is not part of the UAL (unified
>> assembly language) specification - it was deprecated a long time ago.
>> The correct names these days all start with a V - the disassembler
>> output shows the modern form.
>> The legacy name for vmrs was fmrx.
>> R.

You won't find (well are extremely unlikely to find) any documentation 
for the legacy mnemonics online - the reference I have is from the ARMv5 
ARM ARM from nearly 20 years ago, which was in paper form.

The current UAL syntax is documented in the Arm ARM, which you can 
download from - follow the links to the architecture.

There's also a fairly good list of the mapping between the legacy 
mnemonics and UAL for VFP here:


  reply	other threads:[~2022-10-04 10:03 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-03 14:41 Umesh Kalappa
2022-10-03 15:48 ` Richard Earnshaw
2022-10-03 15:54   ` Richard Earnshaw
2022-10-04  4:26     ` Umesh Kalappa
2022-10-04 10:03       ` Richard Earnshaw [this message]
2022-10-04 15:10         ` Joseph Myers

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).