From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@quanstro.net>
Date: Mon, 21 Nov 2011 17:08:47 -0500
To: 9fans@9fans.net
Message-ID: <1f44256f014adb8ba778c7fdf5951b43@brasstown.quanstro.net>
In-Reply-To: <CAOw7k5hcpmt26NppfrFENPWS9_g6jD=XMhQzVMeS1usGQrwL0w@mail.gmail.c>
References: <93653898c4ceb27355b5fa1e548176aa@brasstown.quanstro.net>
	<CAOw7k5hcpmt26NppfrFENPWS9_g6jD=XMhQzVMeS1usGQrwL0w@mail.gmail.c>
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Subject: Re: [9fans] sysrfork fp bug?
Topicbox-Message-UUID: 42ce8840-ead7-11e9-9d60-3106f5b1d025

On Mon Nov 21 10:34:15 EST 2011, charles.forsyth@gmail.com wrote:
> registers are dead on entry to a function, so there's no point in saving
> particular values, because they won't be used. on an amd64, however,
> the kernel should
> reset the FP-used flag, to cause the preset values to be set in the high FP
> registers if the fork'd process does touch the FP.
>

why does pc/trap.c:/^syscall take pains to save the fp registers, then?

- erik