basic os stuff

Makefile

@@ -0,0 +1,95 @@
+# -------------------------------------------------------
+# Real Mode OS Makefile
+# Tools: NASM, OpenWatcom (wcc/wlink), QEMU
+# -------------------------------------------------------
+
+# Tools
+NASM        := nasm
+WCC         := wcc
+WLINK       := wlink
+QEMU        := qemu-system-i386
+DD          := dd
+
+# Flags
+NASM_BIN    := -f bin
+NASM_OBJ    := -f obj
+WCC_FLAGS   := -ms -0 -wx -s -ecc   # small model, 8086, warnings, no stack check, cdecl
+QEMU_FLAGS   = -fda $(IMG) -monitor stdio
+
+# Output names
+BOOT_SRC    := boot.asm
+ENTRY_SRC   := entry.asm
+KMAIN_SRC   := kmain.c
+LINK_FILE   := kernel.lnk
+
+BOOT_BIN    := bootloader.bin
+ENTRY_OBJ   := entry.obj
+KMAIN_OBJ   := kmain.obj
+KERNEL_BIN  := kernel.bin
+IMG         := floppy.img
+
+BIOS_SRC := bios.asm
+BIOS_OBJ := bios.obj
+
+
+
+# -------------------------------------------------------
+# Default target
+# -------------------------------------------------------
+.PHONY: all clean run debug
+
+all: $(IMG)
+
+# -------------------------------------------------------
+# Bootloader — flat binary
+# -------------------------------------------------------
+$(BOOT_BIN): $(BOOT_SRC)
+	$(NASM) $(NASM_BIN) $< -o $@
+
+# -------------------------------------------------------
+# Kernel entry point — OMF object
+# -------------------------------------------------------
+$(ENTRY_OBJ): $(ENTRY_SRC)
+	$(NASM) $(NASM_OBJ) $< -o $@
+
+# -------------------------------------------------------
+# C kernel — OMF object via OpenWatcom
+# -------------------------------------------------------
+$(KMAIN_OBJ): $(KMAIN_SRC)
+	$(WCC) $< $(WCC_FLAGS) -fo=$@
+
+$(BIOS_OBJ): $(BIOS_SRC)
+	$(NASM) $(NASM_OBJ) $< -o $@
+
+$(KERNEL_BIN): $(ENTRY_OBJ) $(BIOS_OBJ) $(KMAIN_OBJ) $(LINK_FILE)
+	$(WLINK) @$(LINK_FILE)
+
+# -------------------------------------------------------
+# Floppy image
+# -------------------------------------------------------
+$(IMG): $(BOOT_BIN) $(KERNEL_BIN)
+	$(DD) if=/dev/zero    of=$@          bs=512 count=2880
+	$(DD) if=$(BOOT_BIN)  of=$@ conv=notrunc
+	$(DD) if=$(KERNEL_BIN) of=$@ seek=1 conv=notrunc bs=512
+
+# -------------------------------------------------------
+# Run in QEMU
+# -------------------------------------------------------
+run: $(IMG)
+	$(QEMU) $(QEMU_FLAGS)
+
+# -------------------------------------------------------
+# Debug — QEMU with GDB stub and interrupt logging
+# -------------------------------------------------------
+debug: $(IMG)
+	$(QEMU) $(QEMU_FLAGS) \
+		-s -S \
+		-d int \
+		-D qemu.log
+
+# -------------------------------------------------------
+# Clean
+# -------------------------------------------------------
+clean:
+	rm -f $(BOOT_BIN) $(ENTRY_OBJ) $(KMAIN_OBJ) $(KERNEL_BIN) $(IMG) $(BIOS_OBJ)\
+	      kernel.map qemu.log