Path: ...!3.eu.feeder.erje.net!feeder.erje.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>
Newsgroups: comp.arch
Subject: Re: Address space limits
Date: Sat, 4 May 2024 14:59:26 -0700
Organization: A noiseless patient Spider
Lines: 15
Message-ID: <v16b3u$1dm6l$2@dont-email.me>
References: <v0s17o$2okf4$2@dont-email.me>
 <62dff0b888855a31ec10c0597669423f@www.novabbs.org>
 <v0soai$30rmc$3@dont-email.me>
 <f2ac45ffe1718a0b0070f027f0e5f58c@www.novabbs.org>
 <20240501225652.00002853@yahoo.com>
 <jwvh6fhnuzu.fsf-monnier+comp.arch@gnu.org> <v0uppp$3fitf$2@dont-email.me>
 <v1521l$15g68$1@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Injection-Date: Sat, 04 May 2024 23:59:26 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="00566bb81b0a3452542610785f934900";
	logging-data="1497301"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1/EAoIqsB1I8xcITF5Arua1/O5B9WVUKm4="
User-Agent: Mozilla Thunderbird
Cancel-Lock: sha1:OjDIBfPjPWrUQIDBcu/nq3YfAvY=
In-Reply-To: <v1521l$15g68$1@dont-email.me>
Content-Language: en-US
Bytes: 1999

On 5/4/2024 3:18 AM, Thomas Koenig wrote:
> Lawrence D'Oliveiro <ldo@nz.invalid> schrieb:
> 
>> Intel pushed this thing called the “x32” ABI into the Linux kernel (and
>> possibly some other places) some years ago. This was using the AMD64
>> instruction set, but with only 32-bit pointers. This way, you got the
>> benefit of the extra registers, without the overhead of the longer
>> addresses.
> 
> That was Donald Knuth's idea.

Storing meta data in actual pointers, aka aligned on a larger boundary, 
is critical to many advanced lock/wait free algorithms as well. I 
remember storing an actual reference count in pointers before for a 
special type of counting.