working code v1

Makefile

@@ -0,0 +1,17 @@
+CROSS_COMPILE = arm-none-eabi-
+
+build: start.S
+	$(CROSS_COMPILE)gcc -x assembler-with-cpp -c -O0 -g3 -mcpu=cortex-m4 -mthumb -Wall -o start.o start.S
+	$(CROSS_COMPILE)gcc start.o -mcpu=cortex-m4 -mthumb -Wall --specs=nosys.specs -nostdlib -lgcc -T./ldscript.ld -o start.elf
+	$(CROSS_COMPILE)objcopy -O binary -F elf32-littlearm start.elf start.bin
+
+qemu: build
+	qemu-system-gnuarmeclipse --verbose --verbose --board STM32F4-Discovery \
+		--mcu STM32F407VG -d unimp,guest_errors \
+		--semihosting-config enable=on,target=native -s -S \
+		--image start.bin
+
+clean:
+	rm *.o
+	rm *.elf
+	rm *.bin