From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@quanstro.net>
Date: Thu, 12 Jun 2014 09:41:53 -0400
To: 9fans@9fans.net
Message-ID: <623b64d7e9aa7b9a8a91c0d3cda2819a@brasstown.quanstro.net>
In-Reply-To: <2b4c21e3aa0b13cd88427a6cbd0d8537@felloff.net>
References: <2b4c21e3aa0b13cd88427a6cbd0d8537@felloff.net>
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
Subject: Re: [9fans] 9syscall
Topicbox-Message-UUID: faa4869e-ead8-11e9-9d60-3106f5b1d025

On Thu Jun 12 09:35:29 EDT 2014, cinap_lenrek@felloff.net wrote:
> because the kernel assumes that returned vlong is passed
> by reference in the first argument, where on amd64, the
> (amd64) calling convention returns it in 64 bit AX register.
>
> so seek() is a library func that emulates the previous convention
> for _seek() syscall.

that's not how the amd64 kernel has worked.  the registers are 64 bits,
the return value, regardless of where it is is 64 bits.  for example, anything
returning an address would already just work, such as segbrk.

- erik