OS := $(shell uname)

ifeq ($V, 1)
  Q =
  S =
else
  MAKEFLAGS += --no-print-directory
  S ?= -s
  Q ?= @
endif

export V Q S

LINUX_VERSION ?= 0.11
LINUX_SRC     := src
LINUX_IMAGE ?= $(LINUX_SRC)/Image
# src/boot/bootsect.sym, src/boot/setup.sym
DST ?= $(if $(LINUX_DST), $(LINUX_DST), $(LINUX_SRC)/kernel.sym)

TOOL_DIR := tools
ROOTFS_DIR := rootfs
CALLGRAPH_DIR := callgraph

# Xterminal: lxterminal, terminator ...
ifeq ($(shell env | grep -q ^XDG; echo $$?), 0)
  XTERM ?= $(shell echo `tools/xterm.sh lxterminal`)
else
  XTERM := null
endif
  GDB ?= gdb

# Qemu
QEMU_PATH =
QEMU ?= qemu-system-i386
MEM  ?= 16M

# Bochs
#BOCHS ?= tools/bochs/bochs-debugger
BOCHS_PATH =
BOCHS_PREBUILT ?= 1
BOCHS_PREBUILT_PATH = ${TOOL_DIR}/bochs

BOCHS ?= bochs

# VM configuration
VM_CFG = $(TOOL_DIR)/.vm.cfg

# Tool for specify root device
SETROOTDEV = RAMDISK_START=$(RAMDISK_START) $(TOOL_DIR)/setrootdev.sh

# Specify the Rootfs Image file
HDA_IMG = hdc-0.11.img
FLP_IMG = rootimage-0.11
RAM_IMG = rootram.img

# Ramdisk start offset and size, in Kb
RAMDISK_START ?= 256

# Tool for call graph generation
CG = $(TOOL_DIR)/callgraph

_QEMU_OPTS = -m $(MEM) -boot c 2>/dev/null
QEMU_OPTS  = -m $(MEM) -boot a -fda $(LINUX_IMAGE) 2>/dev/null


# To using this kvm feature in hardisk boot, please must enable cpu virtualization in bios
#
# Usage: CTRL+ALT+Delete --> Delete --> bios features --> Intel virtualization technology --> enabled
#

QEMU_PREBUILT_PATH= $(TOOL_DIR)/qemu
# Linux 0.11 floppy support is broken in new qemu version, so, please use prebuilt 0.10.6 qemu by default
# But the harddisk support is ok in both of old and new qemu, use qemu here to get possible kvm speedup
ifeq ($(filter $(MAKECMDGOALS),start-hd boot-hd hd-boot hd-start debug-hd),$(MAKECMDGOALS))
   QEMU_PREBUILT ?= 0
else
   QEMU_PREBUILT ?= 1
endif

# Only enable kvm for new qemu, the old one prebuilt in tools/qemu/ not work with kvm
ifeq ($(QEMU_PREBUILT),0)
   # KVM speedup for x86 architecture, assume our host is x86 currently
   QEMU := sudo $(QEMU)
   ifneq ($(findstring debug,$(MAKECMDGOALS)),debug)
     KVM_DEV ?= /dev/kvm
     ifeq ($(KVM_DEV),$(wildcard $(KVM_DEV)))
       QEMU_OPTS += -enable-kvm
       _QEMU_OPTS += -enable-kvm
     endif
   endif
endif

ifeq ($(OS), Linux)
  ifeq ($(QEMU_PREBUILT), 1)
    QEMU_PATH = $(QEMU_PREBUILT_PATH)
    QEMU_XOPTS += -no-kqemu -L $(QEMU_PATH)
  endif
  ifeq ($(BOCHS_PREBUILT), 1)
    BOCHS_PATH = $(BOCHS_PREBUILT_PATH)
  endif
endif

ifeq ($(OS), Darwin)
  GDB := tools/mac/gdb
endif