Make osdev example more uniform with the hello world

README.md

@@ -7,9 +7,10 @@ Hello world programs that run without an operating system.
     1.  [min](min.S)
     1.  [No ld script](no-ld-script/)
     1.  [NASM](nasm/)
-    1.  [bios_one_char](bios_one_char.S)
-    1.  [bios_hello_world](bios_hello_world.S)
-    1.  [shutdown_apm](shutdown_apm.S)
+    1.  [BIOS one char](bios_one_char.S)
+    1.  [BIOS hello world](bios_hello_world.S)
+    1.  [APM shutdown](apm_shutdown.S)
+    1.  [APM shutdown 2](apm_shutdown2.S)
     1.  [Multiboot](multiboot/)
     1.  TODO not working
         1. [UEFI](uefi/)
@@ -38,7 +39,7 @@ To run on real hardware, insert an USB, determine its device (`/dev/sdX`) with:
     sudo lsblk
     sudo fdisk -l
 
-Run:
+Pick the `.img` file that you wan to run and:
 
     sudo dd if=bios_hello_world.img of=/dev/sdX
 

multiboot/osdev/Makefile

@@ -1,21 +1,22 @@
 .POSIX:
 
-BIN := isodir/boot/main.bin
-MAIN := main.iso
+ISODIR := iso
+MULTIBOOT := $(ISODIR)/boot/main.elf
+MAIN := main.img
 
 .PHONY: clean run
 
 $(MAIN):
 	as -32 boot.S -o boot.o
 	gcc -c kernel.c -ffreestanding -m32 -o kernel.o -std=gnu99
-	gcc -ffreestanding -m32 -nostdlib -o '$(BIN)' -T linker.ld boot.o kernel.o -lgcc
-	grub-mkrescue -o main.iso isodir
+	gcc -ffreestanding -m32 -nostdlib -o '$(MULTIBOOT)' -T linker.ld boot.o kernel.o -lgcc
+	grub-mkrescue -o '$@' '$(ISODIR)'
 
 clean:
-	rm -f *.o '$(BIN)' '$(MAIN)'
+	rm -f *.o '$(MULTIBOOT)' '$(MAIN)'
 
 run: $(MAIN)
 	qemu-system-i386 -cdrom '$(MAIN)'
 	# Would also work.
 	#qemu-system-i386 -hda '$(MAIN)'
-	#qemu-system-i386 -kernel myos.bin
+	#qemu-system-i386 -kernel '$(MULTIBOOT)'

multiboot/osdev/iso/boot/grub/grub.cfg

@@ -0,0 +1,5 @@
+set timeout=0
+set default="0"
+menuentry "main" {
+	multiboot /boot/main.elf
+}

multiboot/osdev/isodir/boot/grub/grub.cfg

@@ -1,3 +0,0 @@
-menuentry "main" {
-	multiboot /boot/main.bin
-}

nasm/Makefile

@@ -2,7 +2,7 @@
 
 BASENAME ?= bios_hello_world
 IN_EXT ?= .asm
-OUT_EXT ?= .bin
+OUT_EXT ?= .img
 
 OUT := $(BASENAME)$(OUT_EXT)
 

no-ld-script/README.md

@@ -1,9 +0,0 @@
-# No ld script
-
-Hello world using the default `ld` script, no explicit one set with `-T`. Uses:
-
-- `-tText`
-- `.org` inside each assembly file
-- `_start` must be present to avoid a warning, since the default linker script expects it
-
-Less convenient, but a little less code if you are using a single file.

no-linker-script/README.md

@@ -0,0 +1,9 @@
+# No linker script
+
+Hello world using the default `ld` script, not an explicit one set with `-T`. Uses:
+
+- `-tText`
+- `.org` inside each assembly file
+- `_start` must be present to avoid a warning, since the default linker script expects it
+
+Less stable, but more convenient for quick and dirty tests.

printf/README.md

@@ -2,4 +2,4 @@
 
 Minimal boot sector example that does nothing, just halts immediately, generated with `printf` byte by byte.
 
-You can get more minimal than this.
+You can't get more minimal than this.