successfully using assembler to generate .hex rather than writing straight machine code

test/Makefile

@@ -13,8 +13,11 @@ LDFLAGS = -T test.ld
 %.o: %.S
 	$(AS) $(ASFLAGS) $^ -o $@
 
+%.o: %.c
+	$(CC) $(CFLAGS) $^ -o $@
+
 %.elf: %.o
 	$(LD) $(LDFLAGS) $^ -o $@
 
 test.hex: test.elf
-	riscv64-linux-gnu-objdump -s $^ | sed -n '/0000/,$$p' | cut -f3-6 -d ' ' | sed -e 's/ /\n/g' > $@
+	riscv64-linux-gnu-objdump -s $^ | sed -n '/0000/,$$p' | cut -f3-6 -d ' ' | sed -e 's/ /\n/g' | sed 's/^\(..\)\(..\)\(..\)\(..\)/\4\3\2\1/' > $@