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From: Paul Koning <>
To: jacob navia <>
Cc: Palmer Dabbelt <>,,
Subject: Re: P.S. Follow up to my last post
Date: Fri, 25 Aug 2023 13:03:31 -0400	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

> On Aug 25, 2023, at 12:10 PM, jacob navia <> wrote:
> OK.
> 1) We agree that the -march=rv64gc_zbb option is completely undocumented and impossible for the user to know.
> 2) We agree that « gnu gas » is an assembler whose duty is to assemble instructions. But « gas » will refuse to assemble those instructions. 
>  Why is that? It is the responsibility of the programmer or the compiler to write the instructions that are present in this or another machine. 
>  Why the assembler thinks it is necessary to forbid some instructions???

It's reasonable for the assembler to enforce ISA variations, based on what it's told in the -march switch.  If so, then (a) gcc has to pass that switch, and (b) gcc can't add a variant that gas doesn't know about.

Is that the case here?  Are you invoking the assembler manually or having it done for you by gcc?  If the former, the -march switch is your responsibility; if the latter, then gcc is responsible for getting it right.


  reply	other threads:[~2023-08-25 17:03 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <>
2023-08-25 15:32 ` Palmer Dabbelt
2023-08-25 16:10   ` jacob navia
2023-08-25 17:03     ` Paul Koning [this message]
2023-08-25 19:44       ` jacob navia
2023-08-28  6:17         ` Jan Beulich
2023-08-28  7:04           ` jacob navia
2023-08-25 11:52 jacob navia
2023-08-25 12:00 ` Jan Beulich
2023-08-25 13:07   ` jacob navia
2023-08-25 13:30     ` Jan Beulich
2023-08-25 13:40       ` Paul Koning

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