musl gcc compiler generating "udiv" on a A9mp ARM core...

musl gcc compiler generating "udiv" on a A9mp ARM core...

[Ovi Nastai]

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Hi,

I have  an A9mp based SoC.

My tool generates the “udiv” opcode, that it is not supported by the A9mp.
I also see the “__aeabi_uidiv” at times.

I need to have the tool generating exclusively “__aeabi_uidiv”, on my A9mp
system.



This is the tool’s version:

…

[onastai@bldsrv-ott-03 user]$
../../../../../toolchains/gcc-arm-tzos-musl-4_8-2015q1/bin/arm-tzos-musl-gcc
--version

arm-tzos-musl-gcc (GNU Tools for ARM Embedded Processors) 4.8.4 20140725
(release) [ARM/embedded-4_8-branch revision 213147]

Copyright (C) 2013 Free Software Foundation, Inc.

…

This is the command line (to show the flags):

…

../../../../../toolchains/gcc-arm-tzos-musl-4_8-2015q1/bin/arm-tzos-musl-gcc
-I. -I../../../../kernel/api -MD -MP -mcpu=cortex-a9 -mtune=mpcore
-mfpu=vfpv3 -D__TZOS__ -O2 -g -Wall -Werror  -std=gnu99 -D_POSIX_SOURCE -c
signals_tests.c -o bin/signals_tests.o

../../../../../toolchains/gcc-arm-tzos-musl-4_8-2015q1/bin/arm-tzos-musl-g++
bin/signals_tests.o   -o user.elf

…



Question: are there any flags to instruct the tool to NOT generate the
“udiv” opcodes, and replace them with “sw division” (i.e. “__aeabi_uidiv) ?





Tnx,

Ovi

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Re: musl gcc compiler generating "udiv" on a A9mp ARM core...

[Sebastian Gottschall]

one hint. your compile flags are likelly wrong. mpcore is not cortex-a9
try -mcpu=armv6k
but would be better if you can tell me the exact cpu brand and name
if its the broadcom northstar cortext a9 cpu, the following flags are 
working good.
-march=armv7-a -mcpu=cortex-a9 -mtune=cortex-a9 -msoft-float since the 
northstar cpu has no fpu support, vfpv3 would be wrong

consider always that the musl libc library needs to be compiled using 
the same flags, otherwise it will break again

Sebastian



Am 15.08.2016 um 15:51 schrieb Ovi Nastai:
>
> Hi,
>
> I have  an A9mp based SoC.
>
> My tool generates the “udiv” opcode, that it is not supported by the 
> A9mp. I also see the “__aeabi_uidiv” at times.
>
> I need to have the tool generating exclusively “__aeabi_uidiv”, on my 
> A9mp system.
>
> This is the tool’s version:
>
> …
>
> [onastai@bldsrv-ott-03 user]$ 
> ../../../../../toolchains/gcc-arm-tzos-musl-4_8-2015q1/bin/arm-tzos-musl-gcc 
> --version
>
> arm-tzos-musl-gcc (GNU Tools for ARM Embedded Processors) 4.8.4 
> 20140725 (release) [ARM/embedded-4_8-branch revision 213147]
>
> Copyright (C) 2013 Free Software Foundation, Inc.
>
> …
>
> This is the command line (to show the flags):
>
> …
>
> ../../../../../toolchains/gcc-arm-tzos-musl-4_8-2015q1/bin/arm-tzos-musl-gcc 
> -I. -I../../../../kernel/api -MD -MP -mcpu=cortex-a9 -mtune=mpcore 
> -mfpu=vfpv3 -D__TZOS__ -O2 -g -Wall -Werror -std=gnu99 -D_POSIX_SOURCE 
> -c signals_tests.c -o bin/signals_tests.o
>
> ../../../../../toolchains/gcc-arm-tzos-musl-4_8-2015q1/bin/arm-tzos-musl-g++ 
> bin/signals_tests.o   -o user.elf
>
> …
>
> Question: are there any flags to instruct the tool to NOT generate the 
> “udiv” opcodes, and replace them with “sw division” (i.e. 
> “__aeabi_uidiv) ?
>
> Tnx,
>
> Ovi
>


-- 
Mit freundlichen Grüssen / Regards

Sebastian Gottschall / CTO

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