From: Andrew Haley <aph@redhat.com>
To: gcc-help@gcc.gnu.org
Subject: Re: gcc inline asm unknown mnemonics problems
Date: Tue, 20 Sep 2022 11:26:57 +0100 [thread overview]
Message-ID: <ba2d07fe-0e79-2611-dc61-45a8ad6ae380@redhat.com> (raw)
In-Reply-To: <d4eb3730562f130b74d29ba7749d2b4f2be04934.camel@xry111.site>
On 9/20/22 06:39, Xi Ruoyao via Gcc-help wrote:
> On Mon, 2022-09-19 at 21:47 -0700, mike wrote:
>
> /* snip */
>
>> I am having a problem using ldrexb and strexb using inline assembler. The
>> code is running on a RPi4 on ubuntu 20.04LTS.
>>
>> I get an error message "Error: unknown mnemonic `ldrexb' -- `ldrexb
>> x0,[[sp,8]]'"
>
> ldrexb and strexb are Thumb-2 instructions, but RPi4 uses an AArch64
> CPU. AArch64 is an extension of the classic ARM instruction set, not an
> extension of Thumb-2. So you can't use them on AArch64.
The AArch64 name of that instruction is LDAXRB. I'm assuming you're running
a 64-bit kernel: you don't say.
--
Andrew Haley (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671
prev parent reply other threads:[~2022-09-20 10:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-20 4:47 mike
2022-09-20 5:39 ` Xi Ruoyao
2022-09-20 10:26 ` Andrew Haley [this message]
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