Error: selected processor does not support ARM mode `ldralt r5,[r0],#4'

Error: selected processor does not support ARM mode `ldralt r5,[r0],#4'

[Khem Raj]

Hi Matthew

There is a regression that I am seeing on trunk and also 2.23 branch

testcase

/tmp/as.s

ldralt r5,[r1],#4

$ ./gas/as-new -march=armv5te /tmp/a.s
/tmp/a.s: Assembler messages:
/tmp/a.s:1: Error: selected processor does not support ARM mode `ldralt r5,[r1],#4'


The below commit is the casue of this error

Author: mgretton <mgretton>
Date:   Fri Aug 24 08:03:38 2012 +0000

        * gas/config/tc-arm.c (do_rm_rn): New function.
        (do_strlex): Likewise.
        (do_t_strlex): Likewise.
        (insns): Add support for LDRA/STRL instructions.
        * gas/testsuite/gas/arm/armv8-a-bad.l: Update testcase.
        * gas/testsuite/gas/arm/armv8-a-bad.s: Likewise.
        * gas/testsuite/gas/arm/armv8-a.d: Likewise.
        * gas/testsuite/gas/arm/armv8-a.s: Likewise.
        * opcodes/arm-dis.c (arm_opcodes): Add LDRA/STRL instructions.
        (thumb32_opcodes): Likewise.
        (print_arm_insn): Add support for %<>T formatter.


-- 
-Khem

Re: Error: selected processor does not support ARM mode `ldralt r5,[r0],#4'

[Matthew Gretton-Dann]

On 12 September 2012 00:22, Khem Raj <raj.khem@gmail.com> wrote:
> Hi Matthew
>
> There is a regression that I am seeing on trunk and also 2.23 branch
>
> testcase
>
> /tmp/as.s
>
> ldralt r5,[r1],#4
>
> $ ./gas/as-new -march=armv5te /tmp/a.s
> /tmp/a.s: Assembler messages:
> /tmp/a.s:1: Error: selected processor does not support ARM mode `ldralt r5,[r1],#4'

Yes - I agree that's a regression.  Can you please raise the issue in BugZilla?

The problem is that
   ldralt is <LDRA><LT> (in unified syntax ARMv8-A and above) and
<LDR><AL><T> (in divided syntax).

I think this may be the only instruction this applies to - but I will
go away and have a think.

There are a couple of user-source workarounds:

 * Use unified syntax - so ldrtal instead of ldralt.
 * Don't use 'al' -so ldrt and not ldralt.

The binutils fix however is going to take some thinking about, and I
need to discuss with a maintainer what the most acceptable way forward
is.  Please don't expect anything before the end of the week.

Thanks,

Matt

-- 
Matthew Gretton-Dann
Linaro Toolchain Working Group
matthew.gretton-dann@linaro.org