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Subject: RE: [PATCH 2/5] lib/eal: add portable version of
 __builtin_add_overflow
Date: Fri, 3 Jan 2025 09:19:42 +0100
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From: =?iso-8859-1?Q?Morten_Br=F8rup?= <mb@smartsharesystems.com>
To: "Andre Muezerie" <andremue@linux.microsoft.com>,
 "Tyler Retzlaff" <roretzla@linux.microsoft.com>
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> From: Andre Muezerie [mailto:andremue@linux.microsoft.com]
> Sent: Thursday, 2 January 2025 23.33
>=20
> __builtin_add_overflow is gcc specific. There's a need for a portable
> version that can also be used with other compilers.
>=20
> This patch introduces __rte_add_overflow_u8, __rte_add_overflow_u16
> and __rte_add_overflow_u32.

Instead of the proposed three type-specific macros, add one generic =
rte_add_overflow(a, b, res) macro, like rte_bit_test() [1] using =
"_Generic".

[1]: =
https://elixir.bootlin.com/dpdk/v24.11.1/source/lib/eal/include/rte_bitop=
s.h#L130

You may still need the type-specific macros as internal helpers for the =
MSVC implementation.

Furthermore, a 64 bit variant might be useful.

PS: DPDK naming convention typically uses just "8"/"16"/"32" postfix to =
the function name, not "_u8"/"_u16"/"_u32".