On the same note, and to add to what Sebastian said, you should also know that you can change the floating point ABI in Zephyr by setting:

CONFIG_FP_SOFTABI=y
or
CONFIG_FP_HARDABI=y

in your prj.conf.

Carles

On 07/05/2018, 18:50, "devel@... on behalf of Sebastian Boe" <devel@... on behalf of Sebastian.Boe@...> wrote:

Hi,

what the toolchain is saying is that it can't link

libgcc.a into zephyr_prebuilt.elf because they have an incompatible floating point ABI.

Perhaps

c:/program files (x86)/gnu tools arm embedded/7.0 2017q4/bin/../lib/gcc/arm-none-eabi/7.2.1/thumb/v7e-m\libgcc.a(_popcountsi2.o)

uses a soft float ABI. You can determine this by running

"readelf -a libgcc.a"

on the library and grepping for "Tag_FP",
you should see something like

Tag_FP_arch: VFPv2

If it is indeed a soft-float library you could run "find c:/program files (x86)/gnu tools arm embedded/7.0 2017q4 -name libgcc.a"
to see if your toolchain has another libgcc.a that is built for hard-float.

See the similair, but different issue: https://github.com/zephyrproject-rtos/zephyr/issues/5771

________________________________________
From: devel@... <devel@...> on behalf of Abderrezak Mekkaoui <ab.mekka@...>
Sent: Monday, 7 May 2018 6:04:36 PM
To: devel@...
Subject: [Zephyr-devel] problems building a BME680 app: zephyr_prebuilt.elf uses VFP register arguments ....

Hi All,
I am having problems porting a BME680 app to Zephyr. This app uses a
pre-compiled library (libalgobsec.a) provided by Bosch.
It builds and runs correctly on mynewt (using the exact same tool chain
and the same flags). After solving few issues related to stdint I am
struggling with the last issues possibly related incompatibilities
between different libraries.
I think I am using the right compiler and linker flags (see below) but I
may be wrong.
Any hints/help would be greatly appreciated.
Regards
Abderrezak

P.S. I have other apps that build and run correctly using the same tool
chain (but use the default zephyr flags and have no need for an external
binary library). I am using a custom nrf52840 based board.



###########################################################################################################################################################
CMakelists.txt (latest flag settings, many other combinations all failed)

target_link_libraries(app libalgobsec.a)
target_link_libraries(app libm.a)

set(FPU_FOR_cortex-m4 fpv4-sp-d16)
target_link_libraries(app m.a)
zephyr_cc_option(-DFLOAT_ABI_HARD -mcpu=cortex-m4 -mthumb-interwork
-mthumb -mabi=aapcs -mfloat-abi=hard -mfpu=fpv4-sp-d16 -fno-exceptions
-ffunction-sections -fdata-sections )
zephyr_ld_options(-static -specs=nosys.specs -lgcc -Wl,--gc-sections
-nostartfiles -mthumb -mabi=aapcs -mfloat-abi=hard -mfpu=fpv4-sp-d16
-DFLOAT_ABI_HARD -lalgobsec -lm)
#

###########################################################################################################################################################
Error messages (only few lines)

/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld.exe:
error: zephyr\zephyr_prebuilt.elf uses VFP register arguments,
c:/program files (x86)/gnu tools arm embedded/7.0
2017q4/bin/../lib/gcc/arm-none-eabi/7.2.1/thumb/v7e-m\libgcc.a(_popcountsi2.o)
does not
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld.exe:
failed to merge target specific data of file c:/program files (x86)/gnu
tools arm embedded/7.0
2017q4/bin/../lib/gcc/arm-none-eabi/7.2.1/thumb/v7e-m\libgcc.a(_popcountsi2.o)
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld.exe:
error: zephyr\zephyr_prebuilt.elf uses VFP register arguments,
c:/program files (x86)/gnu tools arm embedded/7.0
2017q4/bin/../lib/gcc/arm-none-eabi/7.2.1/thumb/v7e-m\libgcc.a(_udivmoddi4.o)
does not
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld.exe:
failed to merge target specific data of file c:/program files (x86)/gnu
tools arm embedded/7.0
2017q4/bin/../lib/gcc/arm-none-eabi/7.2.1/thumb/v7e-m\libgcc.a(_udivmoddi4.o)
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld.exe:
error: zephyr\zephyr_prebuilt.elf uses VFP register arguments,
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/lib\libm.a(lib_a-sf_exp.o)
does not
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld.exe:
failed to merge target specific data of file
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/lib\libm.a(lib_a-sf_exp.o)
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld.exe:
error: zephyr\zephyr_prebuilt.elf uses VFP register arguments,
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/lib\libm.a(lib_a-sf_exp2_data.o)
does not
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld.exe:
failed to merge target specific data of file
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/lib\libm.a(lib_a-sf_exp2_data.o)
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld.exe:
error: zephyr\zephyr_prebuilt.elf uses VFP register arguments,
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/lib\libm.a(lib_a-sf_fabs.o)
does not
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld.exe:
failed to merge target specific data of file
c:/progra~2/gnutoo~1/70922~1.020/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/lib\libm.a(lib_a-sf_fabs.o)