From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@quanstro.net>
Date: Fri,  9 May 2014 10:31:49 -0400
To: sstallion@gmail.com, 9fans@9fans.net
Message-ID: <9bca01ca1ac85fadafe2959cf3f7af87@mikro.quanstro.net>
In-Reply-To: <CAGGHmKF-upNXMZjzhrmp4zGsFvS25hx2BJeZapndYB0QbusgJw@mail.gmail.com>
References: <51d4d8ec419f841a99baf30ede300c25@brasstown.quanstro.net>
	<CAGGHmKF-upNXMZjzhrmp4zGsFvS25hx2BJeZapndYB0QbusgJw@mail.gmail.com>
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Subject: Re: [9fans] ureg alignment
Topicbox-Message-UUID: e4caf9ac-ead8-11e9-9d60-3106f5b1d025

> Ugh, no! Is there a case where the padding is a problem? Normally
> registers belonging to the same union are uniform in size. Those
> defines will expand anywhere and not behave as expected:
>
> ulong sp = ureg->sp;
>
> This could lead to all sorts of entertaining problems.

any union on a 64-bit machine will get padded out to 0%8 bytes.

also your example

	ulong sp = ureg->sp

will get expanded to

	ulong r13 = ureg->r13

and this is just fine!

- erik