CC =     $(RISCV_HOME)/bin/riscv64-unknown-elf-gcc
AR =     $(RISCV_HOME)/bin/riscv64-unknown-elf-ar
RANLIB = $(RISCV_HOME)/bin/riscv64-unknown-elf-ranlib

CFLAGS = -march=rv32imac -mabi=ilp32 -mcmodel=medlow -ffunction-sections -fdata-sections --specs=nano.specs -O2