chore: rewrite from zero

.editorconfig

@@ -0,0 +1,8 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+charset = utf-8
+indent_style = tab
+indent_size = 4

.gitignore

@@ -2,3 +2,6 @@
 *.img
 *.bin
 *~
+
+*.elf
+*.dump

Makefile

@@ -1,22 +1,41 @@
-all: stupid.img kern.bin
+.SUFFIXES:
+.DELETE_ON_ERROR:
+.DEFAULT_GOAL := all
 
-stupid.img: floppy.bin kern.bin
+AS		= nasm
-	mkdosfs -F 12 -C $@ 1440
+LD		= ld.lld
-	dd status=noxfer conv=notrunc if=floppy.bin of=$@
+OBJDUMP = llvm-objdump
-	mcopy -i $@ kern.bin ::kern.sys
+RM		= rm -f
 
-floppy.bin: boot/floppy.s
+BIN_DIR		= bin
-	nasm -fbin -o $@ $^
+DOC_DIR		= doc
+KERNEL_DIR	= kernel
+LIB_DIR		= lib
+TOOLS_DIR	= tools
 
-kern.bin: kern/kernel.s
+include $(TOOLS_DIR)/build.mk
-	nasm -fbin -o $@ $^
+
+ASFLAGS	= -DSTUPID_VERSION=\"$(shell $(GIT-VERSION))\" -Ilib
+
+GARBADGE	= stupid.img
+
+include $(KERNEL_DIR)/build.mk
+
+all: stupid.img
+
+stupid.img: $(KERNEL_BIN) $(KERNEL_DUMP)
+
+#stupid.img: floppy.bin kern.bin
+#	mkdosfs -F 12 -C $@ 1440
+#	dd status=noxfer conv=notrunc if=floppy.bin of=$@
+#	mcopy -i $@ kern.bin ::kern.sys
+
+%.dump: %.elf
+	$(OBJDUMP) -D $^ > $@
 
 clean:
-	rm -rf floppy.bin kern.bin
+	$(RM) $(GARBADGE)
 
-fclean: clean
+re: clean all
-	rm -rf stupid.img
 
-re: fclean all
+.PHONY: all clean re
-
-.PHONY: all clean fclean re

README.md

@@ -1,4 +1,4 @@
 # StupidOS
 
-16bit real mode Operating System in assembly
+32-bit Operating System in assembly.
 

boot/floppy.s

@@ -1,127 +0,0 @@
-	[ORG 0x7c00]
-	[BITS 16]
-
-	jmp short entry
-	nop
-
-	;; -----------------------------------------------------------
-	;; OEM & Bios Parameter Block
-	;; -----------------------------------------------------------
-	db "StupidOS"
-
-bpb_bytes_per_sector	dw 512 			; bytes per sector
-bpb_sectors_per_cluster	db 1			; sector per cluster
-bpb_reserved_sectors	dw 1			; reserved sector
-bpb_number_of_fats	db 2			; number of FATs
-bpb_root_entries	dw 224			; root entries
-bpb_total_sectors	dw 2880			; total sector
-bpb_media		db 0xF0			; media descriptor type
-bpb_sectors_per_fat	dw 9			; sectors per FAT
-bpb_sectors_per_track	dw 18			; sectors per track
-bpb_heads_per_cylinder	dw 2			; heads per cylinder
-bpb_hidden_sectors	dd 0			; hidden sectors
-bpb_total_sector_big	dd 0			; total sector big
-bpb_drive_number	db 0			; drive number
-bpb_unused		db 0			; unused
-bpb_signature		db 0x29 		; drive signature (0x29 = floppy) 
-bpb_serial_number	dd 0x00000000		; serial number (ignore)
-bpb_volume_label	db 'STUPID DISK'	; volume label
-bpb_filesystem		db 'FAT12   '		; filesystem type
-
-	;; -----------------------------------------------------------
-	;; entry
-	;; -----------------------------------------------------------
-entry:
-	xor ax, ax
-	mov ds, ax
-
-	mov si, msg_boot
-	call boot_print
-	mov si, msg_copyright
-	call boot_print
-reset_disk:
-	xor ah, ah
-	xor dl, dl
-	int 0x13
-	jc reset_disk
-
-	;; load kernel from FAT
-	;; store size of root dir in cx
-	xor cx, cx
-	xor dx, dx
-	mov ax, 0x0020
-	mul word [bpb_root_entries]
-	div word [bpb_bytes_per_sector]
-	xchg ax, cx
-
-	;; store loc of root directory in ax
-	mov al, byte [bpb_number_of_fats]
-	mul word [bpb_sectors_per_fat]
-	add ax, word [bpb_reserved_sectors]
-	;; mov word [datasec], ax
-	;; mov word [datasec], cx
-	
-	mov bx, 0x0200
-	
-hang:
-	jmp hang
-	cli
-	hlt
-
-	;; -----------------------------------------------------------
-	;; Print string using bios interrupt
-	;; -----------------------------------------------------------
-boot_print:
-	pusha
-.loop:
-	lodsb
-	cmp al, 0
-	jz .end
-	mov ah, 0x0E		; bios print
-	mov bx, 0x07
-	int 0x10
-	jmp .loop
-.end:
-	popa
-	ret
-
-fatal_error:
-	pusha
-	mov cx, si
-	mov si, msg_error
-	call boot_print
-	mov si, cx
-	call boot_print
-	mov si, msg_press_any_key
-	call boot_print
-	xor ax, ax
-	int 0x16		; wait keypressed 
-	int 0x19		; reboot
-	popa
-	ret
-
-disk_read_sector:
-	pusha
-	
-	popa
-	ret
-	
-	;; -----------------------------------------------------------
-	;; Variables
-	;; -----------------------------------------------------------
-	msg_boot db "StupidOS - Bootloader", 13, 10, 0
-	msg_copyright db "Copyright (c) d0p1", 13, 10, 0
-	msg_press_any_key db "Press any key...", 13, 10, 0
-
-	msg_error db "[ERROR] ", 0
-	err_kern_not_found db "KERNEL.BIN not found...", 13, 10, 0
-
-	kernel_filename db "KERNEL  BIN"
-
-	;; -----------------------------------------------------------
-	;; End
-	;; -----------------------------------------------------------
-	times 510-($-$$) db 0
-	db 0x55
-	db 0xAA
-	

kern/kernel.s

@@ -1 +0,0 @@
-[BITS 16]

kernel/build.mk

@@ -0,0 +1,21 @@
+include kernel/drivers/build.mk
+
+KERNEL_SRCS	= head.s gdt.s idt.s paging.s lib/log.s
+KERNEL_OBJS	= $(addprefix kernel/, $(KERNEL_SRCS:.s=.o) $(DRIVERS_OBJS))
+KERNEL_BIN	= stupid.elf
+KERNEL_DUMP = $(KERNEL_BIN:.elf=.dump)
+
+KERNEL_ASFLAGS	= $(ASFLAGS) -D__KERNEL__
+
+GARBADGE += $(KERNEL_OBJS) $(KERNEL_BIN) $(KERNEL_DUMP)
+
+$(KERNEL_BIN): $(KERNEL_OBJS)
+	$(LD) -T $(KERNEL_DIR)/linker.ld -nostdlib -o $@ $^
+
+kernel/lib/%.o: lib/base/%.s
+	mkdir -p $(@D)
+	$(AS) -felf -o $@ $< $(KERNEL_ASFLAGS)
+
+kernel/%.o: kernel/%.s
+	$(AS) -felf -o $@ $< $(KERNEL_ASFLAGS)
+

kernel/drivers/build.mk

@@ -0,0 +1,2 @@
+DRIVERS_SRCS	= serial.s
+DRIVERS_OBJS	= $(addprefix drivers/, $(DRIVERS_SRCS:.s=.o))

kernel/drivers/serial.s

@@ -0,0 +1,48 @@
+section .text
+
+COM1 equ 0x3F8
+COM2 equ 0x2F8
+COM3 equ 0x3E8
+COM4 equ 0x2E8
+
+THR equ 0x0
+RBR equ 0x0
+IER equ 0x1
+IIR equ 0x2
+LCR equ 0x3
+MCR equ 0x4
+LSR equ 0x5
+MSR equ 0x7
+DLL equ 0x0
+DLH equ 0x0
+
+%macro COM_OUT 3
+	mov dx, %1+%2
+	mov al, %3
+	out dx, al
+%endmacro
+
+%macro COM_IN 2
+	mov dx, %1+%2
+	in al, dx
+%endmacro
+
+global serial_init
+serial_init:
+	COM_OUT COM1, IER, 0x00
+	COM_OUT COM1, LCR, 0x80
+	COM_OUT COM1, DLH, 0x00
+	COM_OUT COM1, DLL, 0x0C
+
+	COM_OUT COM1, LCR, 0x03
+
+	ret
+
+global serial_write
+serial_write:
+	push ebp
+	mov ebp, esp
+	mov ecx, [ebp + 8]
+	COM_OUT COM1, THR, cl 
+	pop ebp
+	ret

kernel/gdt.s

@@ -0,0 +1,66 @@
+[BITS 32]
+
+section .text
+
+global setup_gdt
+setup_gdt:
+	lgdt [gdt_ptr]
+	jmp 0x08:.flush_cs
+.flush_cs:
+	mov ax, 0x10
+	mov ds, ax
+	mov es, ax
+	mov fs, ax
+	mov gs, ax
+	mov ss, ax
+	ret
+
+section .data
+
+gdt_ptr:
+	dw gdt_entries.end - gdt_entries - 1
+	dd gdt_entries
+
+gdt_entries:
+	;; null descriptor
+	dw 0x0 ; limit
+	dw 0x0 ; base (low)
+	db 0x0 ; base (mid)
+	db 0x0 ; access
+	db 0x0 ; granularity
+	db 0x0 ; base (high)
+
+	;; kernel mode code segment
+	dw 0xFFFF
+	dw 0x00
+	db 0x00
+	db 0x9A
+	db 0xCF
+	db 0x00
+
+	;; kernel mode data segment
+	dw 0xFFFF
+	dw 0x00
+	db 0x00
+	db 0x92
+	db 0xCF
+	db 0x00
+
+	;; user mode code segment
+	dw 0xFFFF
+	dw 0x00
+	db 0x00
+	db 0xFA
+	db 0xCF
+	db 0x00
+
+	;; user mode data segment
+	dw 0xFFFF
+	dw 0x00
+	db 0x00
+	db 0xF2
+	db 0xCF
+	db 0x00
+
+	;; TSS
+.end:

kernel/head.s

@@ -0,0 +1,47 @@
+[BITS 32]
+
+%include "base.inc"
+
+MULTIBOOT_MAGIC equ 0x1BADB002
+MULTIBOOT_ALIGN equ 1 << 0
+MULTIBOOT_MEMINFO equ 1 << 1
+MULTIBOOT_FLAGS equ MULTIBOOT_ALIGN | MULTIBOOT_MEMINFO
+
+section .multiboot
+align 4
+	dd MULTIBOOT_MAGIC
+	dd MULTIBOOT_FLAGS
+	dd -(MULTIBOOT_MAGIC + MULTIBOOT_FLAGS)
+
+section .bss
+align 16
+stack_bottom:
+	resb 16384
+stack_top:
+
+section .text
+global entry
+entry:
+	mov esp, stack_top
+
+	cli
+
+	extern serial_init
+	call serial_init
+
+	extern setup_gdt
+	call setup_gdt
+
+	extern setup_idt
+	call setup_idt
+
+	extern setup_paging
+	call setup_paging
+
+	LOG file
+
+hang:
+	hlt
+	jmp hang
+
+file db __FILE__, 0

kernel/idt.s

@@ -0,0 +1,16 @@
+[BITS 32]
+section .text
+global setup_idt
+setup_idt:
+	lidt [idt_ptr]
+	ret
+
+section .data
+
+idt_ptr:
+	dw idt_entries.end - idt_entries - 1
+	dd idt_entries
+
+idt_entries:
+	times 256 dd 0x00000000, 0x00000000
+.end:

kernel/kernel.s

@@ -0,0 +1,2 @@
+[BITS 32]
+

kernel/linker.ld

@@ -0,0 +1,25 @@
+OUTPUT_ARCH(i386)
+ENTRY(entry)
+
+SECTIONS
+{
+	. = 1M;
+
+	.text : ALIGN(4) {
+		KEEP(*(.multiboot))
+		*(.text)
+	}
+
+	.rodata : ALIGN(4) {
+		*(.rodata)
+	}
+
+	.data : ALIGN(4) {
+		*(.data)
+	}
+
+	.bss : ALIGN(4) {
+		*(COMMON)
+		*(.bss)
+	}
+}

kernel/paging.s

@@ -0,0 +1,20 @@
+[BITS 32]
+
+section .data
+align 4096
+
+page_directory:
+	times 1024 dd 0x00000002
+
+section .text
+
+global setup_paging
+setup_paging:
+	mov eax, page_directory
+	mov cr3, eax
+
+	mov eax, cr0
+	or eax, 0x80000001
+	mov cr0, eax
+
+	ret

lib/base.inc

@@ -0,0 +1,10 @@
+extern log_impl
+
+%macro LOG 1
+	push %1
+	push file
+
+	call log_impl
+
+	add esp, 8
+%endmacro

lib/base/log.s

@@ -0,0 +1,75 @@
+[BITS 32]
+
+%ifdef __KERNEL__
+extern serial_write
+%endif
+
+section .text
+
+putstr:
+	push ebp
+	mov ebp, esp
+	mov ebx, [ebp + 8]
+.loop:
+	mov eax, [ebx]
+	cmp al, 0
+	je .end
+	push eax
+%ifdef __KERNEL__
+	call serial_write
+%else
+%endif
+	add esp, 4
+	inc ebx
+	jmp .loop
+.end:
+	pop ebp
+	ret
+
+putuint:
+	push ebp
+	mov ebp, esp
+
+	mov ebx, [ebp + 8]
+	mov edx, [ebp + 12]
+
+	mov eax, buffer
+	push eax
+	call putstr
+
+	pop ebp
+	ret
+
+global log_impl
+log_impl:
+	push ebp
+	mov ebp, esp
+	mov eax, [ebp + 8]
+
+	push eax
+	call putstr
+	add esp, 4
+
+%ifdef __KERNEL__
+	push ':'
+	call serial_write
+	add esp, 4
+%else
+%endif
+	mov eax, [ebp + 12]
+	push eax
+	call putstr
+	add esp, 4
+
+%ifdef __KERNEL__
+	mov al, 0xA
+	push eax
+	call serial_write
+	add esp, 4
+%else
+%endif
+	pop ebp
+	ret
+
+digits db '0123456789ABCDEF'
+buffer db '0000000000', 0

tools/build.mk

@@ -0,0 +1,9 @@
+define TOOLS_TEMPLATE
+
+$(1) = $$(addprefix $$(TOOLS_DIR)/, $$(shell echo -n $(1) | tr A-Z a-z))
+
+endef
+
+TOOLS = GIT-VERSION
+
+$(foreach tool, $(TOOLS), $(eval $(call TOOLS_TEMPLATE, $(tool))))

tools/git-version

@@ -0,0 +1,16 @@
+#!/bin/env sh
+
+vers="$(git describe --abbrev=4 --match='v[0-9]*' HEAD 2>/dev/null)"
+
+if [ ! -n "$vers" ]; then
+	vers="0.0"
+fi
+
+commit="$(git rev-parse --short HEAD)"
+
+full_vers="${vers}-${commit}"
+if [ -n "$(git status)" ]; then
+	full_vers="${full_vers}-dirty"
+fi
+
+echo -n "${full_vers}"