Add help target to list available targets

Makefile

@@ -1,13 +1,19 @@
 include build/make.config
+include build/make.help
 
 srctree := $(PWD)
 
-all: 
-	$(make) -C $(srctree)/kernel srctree=$(srctree) all
-
-clean:
-	$(make) -C $(srctree)/kernel srctree=$(srctree) clean
-
 include platform/make.$(platform)
 
-.PHONY: all clean
+kernel:
+	$(make) -C $(srctree)/kernel srctree=$(srctree) all
+
+clean: platform_clean
+	$(make) -C $(srctree)/kernel srctree=$(srctree) clean
+
+.hidden:
+
+help:
+	$(call print_help)
+
+.PHONY: all clean help

build/make.help

@@ -0,0 +1,7 @@
+define print_help
+@make -pqR : 2>/dev/null \
+        | awk -v RS= -F: '/^# File/,/^# Finished Make data base/ {if ($$1 !~ "^[#.]") {print $$1}}' \
+        | sort \
+        | grep -E -v -e '^[^[:alnum:]]' -e '^$@$$' \
+				| xargs -I _ echo _
+endef

kernel/Makefile

@@ -17,6 +17,6 @@ $(srctree)/out/kernel.elf: $(o_files)
 	$(cc) $(kernel_cflags) -c -o $@ $<
 
 clean:
-	-rm $(srctree)/out/kernel.elf $(o_files)
+	-rm -f $(srctree)/out/kernel.elf $(o_files)
 
-.PHONY: all clean
+.PHONY: all

platform/make.i386_pc

@@ -1,27 +1,44 @@
 $(srctree)/out/i386_pc/mop3.iso: $(srctree)/out/kernel.elf
-	rm -rf $(srctree)/out/i386_pc/tmp
-	mkdir -p $(srctree)/out/i386_pc/tmp
 	mkdir -p $(srctree)/out/i386_pc/tmp/iso/boot/grub
 	cp $(srctree)/out/kernel.elf $(srctree)/out/i386_pc/tmp/iso/boot
 	cp $(srctree)/platform/i386_pc/grub.cfg $(srctree)/out/i386_pc/tmp/iso/boot/grub
 	grub-mkrescue -o $(srctree)/out/i386_pc/mop3.iso $(srctree)/out/i386_pc/tmp/iso
 
-QEMU_EXTRA ?=
+boot ?= iso
 
-QEMU_OPTS := -M pc \
-						 -cdrom $(srctree)/out/i386_pc/mop3.iso \
-          	 -serial mon:stdio \
-						 $(QEMU_EXTRA)
+qemu_extra ?=
+
+qemu_opts := -M pc \
+             -serial mon:stdio \
+             $(QEMU_EXTRA)
+
+ifeq ($(boot),iso)
+qemu_opts += -cdrom $(srctree)/out/i386_pc/mop3.iso
+endif
 
 ifeq ($(debug),1)
-QEMU_OPTS += -gdb tcp::5557 -S
+qemu_opts += -gdb tcp::5557 -S
 endif
 
 i386_pc_qemu: $(srctree)/out/i386_pc/mop3.iso
-	qemu-system-i386 $(QEMU_OPTS)
+	qemu-system-i386 $(qemu_opts)
 
 i386_pc_bochs: $(srctree)/out/i386_pc/mop3.iso
 	rm -f $(srctree)/bochs.log
 	-bochs -f $(srctree)/platform/i386_pc/bochsrc.txt -q
 
-.PHONY: i386_pc_qemu i386_pc_bochs
+i386_pc_cleandirs:
+	rm -rf $(srctree)/out/i386_pc/tmp
+
+i386_pc_prepdirs:
+	mkdir -p $(srctree)/out/i386_pc/tmp
+
+i386_pc_images: i386_pc_cleandirs i386_pc_prepdirs \
+                $(srctree)/out/i386_pc/mop3.iso \
+                $(srctree)/out/i386_pc/mop3.img
+
+platform_clean: i386_pc_cleandirs
+	-rm -f $(srctree)/out/i386_pc/mop3.iso \
+		$(srctree)/out/i386_pc/mop3.img
+
+.PHONY: i386_pc_qemu i386_pc_bochs i386_pc_images platform_clean