ARM GCC machine options for RTEMS 6

Sebastian Huber sebastian.huber at embedded-brains.de
Fri Jul 3 07:06:31 UTC 2020


Hello,

someone from ARM changed the machine options used to build the RTEMS 
multilibs some time ago (I think GCC 8):

arm-rtems6-gcc -print-multi-lib -march=armv4t
.;
thumb;@mthumb
armv5te+fp/hard;@march=armv5te+fp at mfloat-abi=hard
thumb/armv6-m;@mthumb at march=armv6-m
thumb/armv7-a;@mthumb at march=armv7-a
thumb/armv7-r;@mthumb at march=armv7-r
thumb/cortex-m3;@mthumb at mcpu=cortex-m3
thumb/cortex-m4+nofp;@mthumb at mcpu=cortex-m4+nofp
thumb/armv7-a+simd/hard;@mthumb at march=armv7-a+simd at mfloat-abi=hard
thumb/armv7-r+fp/hard;@mthumb at march=armv7-r+fp at mfloat-abi=hard
thumb/cortex-m4/hard;@mthumb at mcpu=cortex-m4 at mfloat-abi=hard
thumb/cortex-m7/hard;@mthumb at mcpu=cortex-m7 at mfloat-abi=hard
eb/thumb/armv7-r;@mbig-endian at mthumb@march=armv7-r
eb/thumb/armv7-r+fp/hard;@mbig-endian at mthumb@march=armv7-r+fp at mfloat-abi=hard

It seems that our current machine options still map to the right multilib:

arm-rtems6-gcc -print-multi-directory -march=armv7-a -mthumb -mfpu=neon 
-mfloat-abi=hard -mtune=cortex-a9
thumb/armv7-a+simd/hard

arm-rtems6-gcc -print-multi-directory -mthumb -mcpu=cortex-m4 
-mfpu=fpv4-sp-d16 -mfloat-abi=hard
thumb/cortex-m4/hard

arm-rtems6-gcc -print-multi-directory -march=armv7-r -mthumb -mbig-endian
eb/thumb/armv7-r

arm-rtems6-gcc -print-multi-directory -march=armv7-r -mthumb 
-mbig-endian -mfpu=vfpv3-d16 -mfloat-abi=hard
eb/thumb/armv7-r+fp/hard

Should we change the options to match the ones given in the multilib 
definition or should we keep the current options? If we change the 
options, then we can no longer build with GCC 7.



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