Add a simple "kernel" binary that can be used for testing

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

tests/kernel/Makefile

@@ -0,0 +1,20 @@
+NAME	:= kernel
+
+BIN	:= $(NAME).bin
+ELF	:= $(NAME).elf
+OBJ	:= $(NAME).o
+
+all: $(BIN)
+
+$(BIN): $(ELF)
+	objcopy -O binary $< $@
+
+$(ELF): $(OBJ)
+	ld -Ttext=0x00 -nostdlib -static $< -o $@
+
+%.o: %.S
+	gcc -nostdinc -c $< -o $@
+
+clean:
+	rm -f $(BIN) $(ELF) $(OBJ)
+.PHONY: clean

tests/kernel/README

@@ -0,0 +1,16 @@
+Compiling
+---------
+
+You can simply type:
+
+  $ make
+
+to build a 16-bit binary that uses the i8086 instruction set.
+
+Disassembling
+-------------
+
+Use the "-m i8086" command line option with objdump to make sure it knows we're
+dealing with i8086 instruction set:
+
+  $ objdump -d -m i8086 i8086.elf

tests/kernel/kernel.S

@@ -0,0 +1,8 @@
+	.code16gcc
+	.text
+	.globl  _start
+	.type   _start, @function
+_start:
+	# "This is probably the largest possible kernel that is bug free." -- Avi Kivity
+	1:
+	jmp 1b