From a500288079e03fcd88317161e908bd8de98c2c02 Mon Sep 17 00:00:00 2001
From: Jonas 'Sortie' Termansen <sortie@maxsi.org>
Date: Fri, 19 Sep 2014 16:38:40 +0200
Subject: [PATCH] Add sortix.bin makefile target.

---
 Makefile              |  9 +++++++++
 doc/cross-development | 30 ++++++++++++++++++++++++------
 2 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/Makefile b/Makefile
index b0b0b545..41d422db 100644
--- a/Makefile
+++ b/Makefile
@@ -147,6 +147,7 @@ clean-ports:
 .PHONY: clean-builds
 clean-builds:
 	rm -rf "$(SORTIX_BUILDS_DIR)"
+	rm -f sortix.bin
 	rm -f sortix.initrd
 	rm -f sortix.iso
 	rm -f sortix.iso.xz
@@ -215,6 +216,14 @@ release-all-archs:
 	$(MAKE) clean
 	$(MAKE) release HOST=x86_64-sortix
 
+# Kernel
+
+.PHONY: kernel
+kernel: sysroot
+
+sortix.bin: kernel
+	cp "$(SYSROOT)/boot/$(HOST)/sortix.bin" sortix.bin
+
 # Initial ramdisk
 
 $(INITRD): sysroot
diff --git a/doc/cross-development b/doc/cross-development
index aaf19ce5..f051529c 100644
--- a/doc/cross-development
+++ b/doc/cross-development
@@ -97,7 +97,8 @@ commands:
 
   cd ~/sortix &&
   make PREFIX="$CROSS_PREFIX" build-tools &&
-  make PREFIX="$CROSS_PREFIX" install-build-tools
+  make PREFIX="$CROSS_PREFIX" install-build-tools &&
+  make distclean
 
 These tools produce platform independent output so you may wish to install them
 into $HOME/bin or /usr/local/bin or where it suits you in your $PATH.
@@ -188,16 +189,33 @@ completed the above steps correctly, then you can simply do:
 
 This will compile a basic Sortix system into ~/sortix/sysroot with a kernel,
 headers, libraries, programs, everything you need. This isn't a bootable system
-yet. If you have xorriso and grub-mkrescue from GRUB 2 installed, then you can
+yet. You need the combination of a kernel and an initrd to boot Sortix. The
+initrd is a root filesystem entirely in memory that is loaded by the bootloader
+in addition to the kernel. You can generate the initrd in builds/ by running:
+
+  cd ~/sortix &&
+  make HOST=$SORTIX_PLATFORM initrd
+
+If you want a copy of the kernel and initrd in the current directory (rather
+than normally finding them in builds/ and sysroot/), you can run:
+
+  cd ~/sortix &&
+  make HOST=$SORTIX_PLATFORM sortix.bin sortix.initrd
+
+You now have a sortix.bin and sortix.initrd pair. You can boot Sortix using a
+multiboot bootloader by passing them as a multiboot kernel and multiboot
+module/initrd.
+
+If you have xorriso and grub-mkrescue from GRUB 2 installed, then you can
 can build a bootable .iso by typing:
 
   cd ~/sortix &&
   make HOST=$SORTIX_PLATFORM sortix.iso
 
-This will produce a ~/sortix/sortix.iso file that is bootable on real hardware
-and virtual machines. Alternatively, you can take the sortix.bin file and boot
-that with GRUB as a multiboot kernel and sortix.initrd (snapshot of the sysroot)
-as a multiboot module/initrd.
+This will produce a sortix.iso file that is bootable on real hardware and
+virtual machines. This works by first building Sortix system and packaging up an
+initrd, then it create a cdrom image with a bootloader configured to load the
+kernel and initrd stored on the cdrom.
 
 You can clean the source directory fully: