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hedmo
Veteran
Joined: 29 Aug 2009
Posts: 1334
Location: sweden
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 Posted: Sun Apr 03, 2022 3:51 pm Post subject: correct way for arm cflags vs useflag |
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hi all
what is the correct way to use cflags vs useflags for arm ? . ATM i have it like this :
| Code: |
CFLAGS="-O2 -pipe -march=armv7-a -mfpu=neon -mfloat-abi=hard"
CXXFLAGS="${CFLAGS}"
USE="cpu_flags_arm_neon"
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regards hedmo |
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NeddySeagoon
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Joined: 05 Jul 2003
Posts: 54845
Location: 56N 3W
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| Posted: Sun Apr 03, 2022 4:21 pm Post subject: |
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hedmo,
app-portage/cpuid2cpuflags works on ARM.
| Code: | #From a Raspberry Pi4
CPU_FLAGS_ARM="edsp neon thumb vfp vfpv3 vfpv4 vfp-d32 crc32 v4 v5 v6 v7 v8 thumb2" |
| Code: | | USE="cpu_flags_arm_neon" |
is OK, just a bit cluttered.
_________________
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NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
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ElRay70K70H
n00b
Joined: 12 Apr 2022
Posts: 17
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| Posted: Tue Apr 12, 2022 2:59 am Post subject: Re: correct way for arm cflags vs useflag |
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Are you getting errors with: | hedmo wrote: | | Code: | | ... -mfpu=neon -mfloat-abi=hard" |
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I tried those with the regular Raspberry PI OS on an 64-bit 8GB Pi4. As best as I can tell, those options are not supported in 64-bit mode. |
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NeddySeagoon
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Joined: 05 Jul 2003
Posts: 54845
Location: 56N 3W
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| Posted: Tue Apr 12, 2022 10:25 am Post subject: |
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ElRay70K70H,
Welcome to Gentoo.
Both 32 and 64 bit arm have neon but they are different, non interchangeable options.
-mfloat-abi=hard does not make sense on arm64 as the hardware FPU is not optional.
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NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
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hedmo
Veteran
Joined: 29 Aug 2009
Posts: 1334
Location: sweden
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| Posted: Mon Apr 18, 2022 12:22 pm Post subject: |
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sorry for a late reply ...
the more important answer is if i need :
in CFLAGS= ?
regards hedmo |
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Gentoo on ARM
