Other flavours

Posted Dec 13, 2018 13:31 UTC (Thu) by plugwash (subscriber, #29694)
In reply to: Other flavours by cladisch
Parent article: The x32 subarchitecture may be removed

What has changed since then is a mechanism has been introduced to allow 32-bit architectures to use 64-bit time. There has been a mechanism for 32-bit architectures to use 64-bit file offsets for a long time.

Other than time and file offsets I can't think of much that has a pressing need to be 64-bit on 32-bit systems.

Other flavours

Posted Dec 13, 2018 19:02 UTC (Thu) by jccleaver (guest, #127418) [Link] (2 responses)

> What has changed since then is a mechanism has been introduced to allow 32-bit architectures to use 64-bit time. There has been a mechanism for 32-bit architectures to use 64-bit file offsets for a long time.

This absolutely is key. If this decision were to be rolled back in the interests of a meaningfully usable x32, it would be a great step.

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Posted Dec 13, 2018 23:22 UTC (Thu) by farnz (subscriber, #17727) [Link] (1 responses)

Why? 64-bit time for 32-bit architectures is worth the effort because there still exist 32-bit only systems being sold today (ARM Cortex-R range, including new designs, for example, not to mention embedded systems using older ARMv7-A cores, plus anything designed around the DM&P Vortex86 SoCs or RDC's Emkore and IAD chips which are x86 CPUs with no 64-bit support). Thus, we need to address this anyway; these chips are going to be around for a while, and saying that brand new hardware designed in 2019 (or probably 2020) is going to be worthless before 2038 isn't exactly nice.

OTOH, x32 is just a potential speedup for users who could use amd64 or i386 ABIs; it doesn't expand the user base by any significant amount, and does involve engineering effort.

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Posted Dec 14, 2018 8:30 UTC (Fri) by joib (subscriber, #8541) [Link]

I think the argument was that it would be nicer if X32 would use the generic support for 64-bit time_t for 32-bit targets rather than having its own custom way of doing it.