Also my BSP CFLAG in .../arm-xilinx-zynq-rtems-4.11/arm-rtems4.11/xilinx_zynq_zedboard/make/target.cfg is as below: CFLAGS = -march=armv7-a -mthumb -mfpu=neon -mfloat-abi=hard -mtune=cortex-a9 -O2 -g -Wall -Wmissing-prototypes -Wimplicit-function-declaration -Wstrict-prototypes -Wnested-externs