New Makefile target: qemudbg

This target starts qemu in Debug-Mode and GDB.
There is a GDB-Script file script.gdb which is extensible to match your
debugging needs.

Makefile.example

@@ -19,6 +19,8 @@ RANLIB_FOR_TARGET=ranlib
 STRIP_FOR_TARGET=strip
 READELF_FOR_TARGET=readelf
 NASM = nasm
+EMU=qemu
+GDB=gdb
 
 MAKE = make
 NASMFLAGS = -felf32 -g
@@ -71,6 +73,13 @@ $(NAME).elf:
 qemu: newlib tools $(NAME).elf
 	qemu -smp 2 -net nic,model=rtl8139 -net user,hostfwd=tcp::12345-:7 -net dump -kernel metalsvm.elf -initrd tools/initrd.img
 
+qemudbg: newlib tools $(NAME).elf
+	qemu -S -s -smp 2 -net nic,model=rtl8139 -net user,hostfwd=tcp::12345-:7 -net dump -kernel metalsvm.elf -initrd tools/initrd.img
+
+gdb: $(NAME).elf
+	make qemudbg > /dev/null &
+	$(GDB) -x script.gdb
+
 clean:
 	$Q$(RM) $(NAME).elf $(NAME).sym *~
 	$Q$(MAKE) -C tools clean

script.gdb

@@ -0,0 +1,7 @@
+# Constant part of the script
+symbol-file metalsvm.sym
+target remote localhost:1234
+
+# Configure breakpoints and everything as you wish here.
+break main
+continue