From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <0ad26600f43ce6f44c61e6f6d78ed116@swtch.com>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] OS X threads + dynamic linking
From: "Russ Cox" <rsc@swtch.com>
Date: Fri, 21 Apr 2006 20:54:04 -0500
In-Reply-To: <3e1162e60604210924h2a12fd99n171afc7893b5e646@mail.gmail.com>
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> Actually, this code violates the ABI.  The stack needs to be aligned
> on a 16byte address.
>
> http://developer.apple.com/documentation/DeveloperTools/Conceptual/LowLevelABI/index.html
>
> So the assembly block should be:
>
>        asm(
>                "pushal\n"
>                "movl 8(%ebp), %ebx\n"
>                "movl 12(%ebp), %eax\n"
>                "xchgl %esp, %eax\n"
> 	        "subl $0xc, %esp\n"  //need to align the stack... can't just pushl
>                "pushl %eax\n"
>                "call *%ebx\n"
>                "popl %esp\n"
>                "popal\n"
>        );
>
> Just don't compile with -Os because gcc freaking inlines runonstack.
> Whom to throttle for that one?

The real version doesn't use inline assembly, so it's not a problem.
I just wanted a single file demonstrating the problem.

After aligning the stack pointer properly, the x86 OS X code
now in CVS does appear to work.

Thanks very much for tracking this down.

Russ