# TOOLPREFIX = riscv64-linux-gnu
# TOOLPREFIX = toolchain/xpack-riscv-none-elf-gcc-14.2.0-3/bin/riscv-none-elf
TOOLPREFIX = toolchain/gcc/bin/riscv-none-elf

CC = $(TOOLPREFIX)-gcc
AS = $(TOOLPREFIX)-as
LD = $(TOOLPREFIX)-ld
OBJCOPY = $(TOOLPREFIX)-objcopy
OBJDUMP = $(TOOLPREFIX)-objdump

ASFLAGS = -march=rv64gc -mabi=lp64

LDFLAGS = -Tkernel.ld
LDFLAGS += -m elf64lriscv

CFLAGS = -Wall -Werror -O
CFLAGS += -Wno-unused-result
CFLAGS += -mcmodel=medany
CFLAGS += -march=rv64gc -mabi=lp64
CFLAGS += -ffreestanding -fno-common -nostdlib -mno-relax

CFLAGS += -fno-stack-protector # Prevents code that needs libc / runtime support
CFLAGS += -MD # Generate header dependency files (.d)
CFLAGS += -fno-pie -no-pie # Fixed address linking
CFLAGS += -ggdb -gdwarf-2 # GDB debug info
CFLAGS += -fno-omit-frame-pointer # More reliable backtraces in GDB

KCFLAGS += $(CGFLAGS)
KCFLAGS += -DNEPTUNE_KERNEL
KCFLAGS += -Ikern
KCFLAGS += -Ikern/libkern
KCFLAGS += -I.

CFLAGS += -I.
CFLAGS += -Ilib

all: kernel.elf

main: main.o

kernel.elf: entry.o start.o kern/libkern/string.o kern/libkern/proc.o kern/libkern/uart.o kern/libkern/panic.o kern/kalloc.o kern/libkern/memory.o kern/ispinlock.o kern/libkern/spinlock.o kern/libkern/string.o kern/libkern/mini-printf.o
	@echo LD $@
	@$(LD) $(LDFLAGS) -o $@ $^

%.o: %.c
	@echo CC $@
	@$(CC) $(KCFLAGS) -nostdinc -I. -c $< -o $@

%.o: %.S
	@echo AS $@
	@$(AS) $(ASFLAGS) -o $@ $<

qemu: kernel.elf
	@echo QEMU $<
	@qemu-system-riscv64 -machine virt -bios none -nographic -m 128M -smp 4 -kernel kernel.elf

clean:
	rm -f *.o *.elf *.d lib/*.o lib/*.d
	fd -e o -x rm # TODO: Should only depend on posix

-include *.d

# --------------------------------------------------------------------
# Toolchain configuration
# --------------------------------------------------------------------

TOOLCHAIN_DIR := toolchain

# Versions
QEMU_VER := 8.2.6-1
GCC_VER  := 14.2.0-3

# Filenames
QEMU_TARBALL := xpack-qemu-riscv-$(QEMU_VER)-linux-arm.tar.gz
GCC_TARBALL  := xpack-riscv-none-elf-gcc-$(GCC_VER)-linux-arm.tar.gz

# URLs
QEMU_URL := https://github.com/xpack-dev-tools/qemu-riscv-xpack/releases/download/v$(QEMU_VER)/$(QEMU_TARBALL)
GCC_URL  := https://github.com/xpack-dev-tools/riscv-none-elf-gcc-xpack/releases/download/v$(GCC_VER)/$(GCC_TARBALL)

# Paths
QEMU_TARPATH := toolchain/xpack-qemu-riscv-8.2.6-1-linux-arm.tar.gz
GCC_TARPATH := toolchain/xpack-riscv-none-elf-gcc-14.2.0-3-linux-arm.tar.gz

# Extracted directories
QEMU_DIR := $(TOOLCHAIN_DIR)/xpack-qemu-riscv-$(QEMU_VER)
GCC_DIR  := $(TOOLCHAIN_DIR)/xpack-riscv-none-elf-gcc-$(GCC_VER)

# Symlink targets
QEMU_SYM_DIR := xpack-qemu-riscv-$(QEMU_VER)
GCC_SYM_DIR  := xpack-riscv-none-elf-gcc-$(GCC_VER)

# Final symlink/alias
GCC_ALIAS := gcc
QEMU_ALIAS := qemu

QEMU_TARPATH:
	curl -# -L -o $@ $(QEMU_URL)

GCC_TARPATH:
	curl -# -L -o $@ $(GCC_URL)

extractions:
	cd toolchain && tar xf $(QEMU_TARBALL)
	cd toolchain && tar xf $(GCC_TARBALL)

toolchain: $(QEMU_TARPATH) $(GCC_TARPATH)
	mkdir -p toolchain
	cd toolchain && tar xf $(QEMU_TARBALL)
	cd toolchain && tar xf $(GCC_TARBALL)
	cd $(TOOLCHAIN_DIR) && ln -sfn $(QEMU_SYM_DIR) $(QEMU_ALIAS)
	cd $(TOOLCHAIN_DIR) && ln -sfn $(GCC_SYM_DIR)  $(GCC_ALIAS)

distclean: clean
	rm -rf $(TOOLCHAIN_DIR)

.PHONY: all toolchain