RTEMS not compiling with -mfloat-abi=hard in ARM926ejs

Amarnath MB amarnath.mb at mistralsolutions.com
Fri Jan 4 19:52:48 UTC 2019


I'm working on RTEMS 5.0 BSP for a new SOC based on ARM926EJS which has a
VFP9-S Floating point coprocessor inside.
I was able to successfully boot RTEMS and run hello.exe and ticker.exe
testsuite samples using u-boot.

I have enabled VFP from Uboot using the coprocessor instructions given in
In order to use the VFP coprocessor in RTEMS I have added
*CPU_CFLAGS = -mcpu=arm926ej-s -mthumb -mfloat-abi=hard *in the .cfg file
for the BSP.
But during the BSP build, it gives error "configure: error: C compiler
cannot create executables".
How can I enable hard float support in my BSP?

*As a trial, I have built BSP with CPU_CFLAGS = -mcpu=arm926ej-s -mthumb
and manually added*
*CPU_CFLAGS = -mcpu=arm926ej-s -mthumb -mfloat-abi=hard in the makefile
(Makefile.leaf) for application build.*
*In this case, I'm getting error 'error: o-optimize/init.o uses VFP
register arguments, o-optimize/rtems-app.exe does not'*

*As per RTEMS CPU Architecture Supplement Release 5.0.0 (master) Section
3.1.3 Floating Point Unit only*
*VFPv3-D32, **VFPv3-D16 and *
*FPv4-SP-D16 are supported by RTEMS, but VFP9-S Floating point coprocessor
is an *

*implementation of the Vector Floating-point Architecture (VFPv2) which is
not listed in 3.1.3.*
*Does this state that VFP9-S Floating point coprocessor is not supported by

*For your info floating point operations are working fine in the
application built using -mfloat-abi=soft.*

*Thanks in advance for all your precious time.*

*Regards, *

*Amarnath MB*
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