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Olimex Support Forum

OLinuXino Android / Linux boards and System On Modules => A20 => Topic started by: spin on November 22, 2013, 11:29:21 PM

Title: Compiler optimization for A20
Post by: spin on November 22, 2013, 11:29:21 PM
I am porting some HAM programs in Debian for A20-Olinuxino.
Some are in C, other C++ and also in Fortran.
What flag I need to use for compiler optimization?
Need I to use -march=armv7, -float-abi=hard, -mfpu=vfp flags?

Regards
Franco Spinelli
IW2DHW
Title: Re: Compiler optimization for A20
Post by: isidoro on November 25, 2013, 01:20:49 PM
Xfer suggested :
QuoteCFLAGS="-march=armv7-a -mtune=cortex-a7 -mfpu=neon-vfpv4 -ffast-math -Ofast"

and get very nice performances.


https://www.olimex.com/forum/index.php?topic=1653.msg7970#msg7970
Title: Re: Compiler optimization for A20
Post by: spin on November 25, 2013, 09:39:44 PM
Using as suggested I get:

gcc -I. -fbounds-check -march=armv7-a -mtune=cortex-a7 -mfpu=neon-vfpv4 -ffast-math -c igray.c
cc1: error: bad value (cortex-a7) for -mtune switch

I am compiling on A20 and using Debian image from Olimex and gcc version is gcc (Debian 4.6.3-14) 4.6.3

Is a GCC version problem?

Regards

Franco Spinelli


Title: Re: Compiler optimization for A20
Post by: isidoro on November 26, 2013, 10:17:59 AM
Maybe cc version,
I'm using : cc (GCC) 4.7.2 from archlinux distro.
Also you can try using linaro, I posted a linaro 13.10 image few weeks ago, it includes gcc 4.8.
Title: Re: Compiler optimization for A20
Post by: spin on November 26, 2013, 09:36:04 PM
Installed 4.7 version of Gcc/G++/Gfortran and now suggested CFLAGS is working

Unfortunately not a big improvement on Wsjtx program.

Regards

Franco Spinelli
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