# Pactor64 — Raspberry Pi 5 Makefile (AArch64)
# Pure clang toolchain — no GNU tools
# ============================================================

CC          = clang-21
LD          = ld.lld-21
OBJCOPY     = llvm-objcopy-21
OBJDUMP     = llvm-objdump-21
READELF     = llvm-readelf-21
NM          = llvm-nm-21
STRIP       = llvm-strip-21

TARGET      = --target=aarch64-none-elf
CPU         = -mcpu=cortex-a76

CC_FLAGS    = $(TARGET) $(CPU) \
              -O2 -Wall -Wextra \
              -ffreestanding -fno-builtin -fno-stack-protector \
              -fno-pic -fno-pie \
              -mgeneral-regs-only \
              -nostdlib -nostdinc \
              -Iinclude

AS_FLAGS    = $(TARGET) $(CPU) \
              -ffreestanding

LD_FLAGS    = -T linker.ld -nostdlib --static

BUILD_DIR   = build
KERNEL_IMG  = $(BUILD_DIR)/kernel8.img
KERNEL_ELF  = $(BUILD_DIR)/pactor64.kernel

# Source files
ASM_SRC     = kernel/entry.S
C_SRC       = kernel/main.c
ASM_OBJ     = $(patsubst %,$(BUILD_DIR)/%.o,$(ASM_SRC))
C_OBJ       = $(patsubst %,$(BUILD_DIR)/%.o,$(C_SRC))
OBJS        = $(ASM_OBJ) $(C_OBJ)

# ============================================================
# Targets
# ============================================================

.PHONY: all clean run verify

all: $(KERNEL_IMG)
	@echo "========================================="
	@echo "  Pi 5 kernel: $(KERNEL_IMG)"
	@echo "  Size: $$(stat -c%s $(KERNEL_IMG)) bytes"
	@echo "========================================="

$(KERNEL_IMG): $(KERNEL_ELF)
	$(OBJCOPY) -O binary $< $@

$(KERNEL_ELF): $(OBJS) linker.ld
	$(LD) $(LD_FLAGS) -o $@ $(OBJS)

# Assembly files
$(BUILD_DIR)/%.S.o: %.S | $(BUILD_DIR)
	@mkdir -p $(dir $@)
	$(CC) $(AS_FLAGS) -c $< -o $@

# C files
$(BUILD_DIR)/%.c.o: %.c | $(BUILD_DIR)
	@mkdir -p $(dir $@)
	$(CC) $(CC_FLAGS) -c $< -o $@

$(BUILD_DIR):
	mkdir -p $@

clean:
	rm -rf $(BUILD_DIR)

# Verify multiboot (not applicable for Pi, but check ELF)
verify: $(KERNEL_ELF)
	$(READELF) -h $< | grep -E "Class|Machine|Entry"
	$(OBJDUMP) -d $< | head -20

# Copy to SD card (mount point as argument)
# Usage: make deploy SD=/media/sdcard
deploy: $(KERNEL_IMG)
	@if [ -z "$(SD)" ]; then echo "Usage: make deploy SD=/path/to/sdcard"; exit 1; fi
	cp $(KERNEL_IMG) $(SD)/kernel8.img
	cp boot/config.txt $(SD)/config.txt
	@echo "Deployed to $(SD)"

# Disassemble
disasm: $(KERNEL_ELF)
	$(OBJDUMP) -d $<

# QEMU emulation (limited — Pi 5 not fully supported in QEMU)
# Use: make qemu (requires qemu-system-aarch64)
run:
	@echo "To run on Pi 5: copy kernel8.img + config.txt to SD card"
	@echo "To emulate: qemu-system-aarch64 -M raspi3b -kernel $(KERNEL_IMG) -serial stdio"