banan-os/bootloader/boot.S

.code16

#########################################
#
# STAGE 1 BOOTLOADER
#
# its sole purpose is to load stage2 from
# bios boot partition
#
#########################################

.section .stage1

.global stage1_main
stage1_main:
	# setup segments
	movw $0, %ax
	movw %ax, %ds
	movw %ax, %es

	# setup stack
	movw %ax, %ss
	movl $0x7C00, %esp

	# save boot disk number
	call read_stage2_into_memory

	jmp stage2_main

.global print_and_halt
print_and_halt:
	call puts
halt:
	hlt
	jmp halt


#########################################
#
# STAGE 2 BOOTLOADER
#
#########################################

.section .stage2

stage2_main:
	# clear screen and enter 80x25 text mode
	movb $0x03, %al
	movb $0x00, %ah
	int $0x10

	# print hello message
	movw $hello_msg, %si
	call puts; call print_newline

	call get_memory_map
	call read_user_command_line

	call print_newline

	movw $start_kernel_load_msg, %si
	call puts; call print_newline

	call print_memory_map

	call find_root_disk
	call find_root_partition

	call print_root_partition_info
	call print_newline

	call has_ext2_filesystem
	testb %al, %al
	jz print_and_halt

	call ext2_find_kernel

	jmp halt

hello_msg:
	.asciz "This is banan-os bootloader"

start_kernel_load_msg:
	.asciz "Starting to load kernel"
Bootloader: Start work on bootloader I wrote a fast first stage bootloader and a installer to put it into a disk image. 2023-11-09 22:42:47 +02:00			`.code16`

			`#########################################`
			`#`
			`# STAGE 1 BOOTLOADER`
			`#`
			`# its sole purpose is to load stage2 from`
			`# bios boot partition`
			`#`
			`#########################################`

			`.section .stage1`

Bootloader: Split bootloader into multiple files This cleans up the code since bootloader is starting to near 1k lines 2023-11-14 03:26:03 +02:00			`.global stage1_main`
Bootloader: Continue work on bootloader Bootloader can now get the memory map and read cmdline from user. Now 'just' video mode query, ext2 and ELF parsing are needed :D 2023-11-11 22:49:00 +02:00			`stage1_main:`
Bootloader: Start work on bootloader I wrote a fast first stage bootloader and a installer to put it into a disk image. 2023-11-09 22:42:47 +02:00			`# setup segments`
			`movw $0, %ax`
			`movw %ax, %ds`
			`movw %ax, %es`

			`# setup stack`
			`movw %ax, %ss`
Bootloader: Find root partition from GPT header 2023-11-13 18:55:48 +02:00			`movl $0x7C00, %esp`
Bootloader: Start work on bootloader I wrote a fast first stage bootloader and a installer to put it into a disk image. 2023-11-09 22:42:47 +02:00
			`# save boot disk number`
Bootloader: Split bootloader into multiple files This cleans up the code since bootloader is starting to near 1k lines 2023-11-14 03:26:03 +02:00			`call read_stage2_into_memory`
Bootloader: Find root partition from GPT header 2023-11-13 18:55:48 +02:00
Bootloader: Continue work on bootloader Bootloader can now get the memory map and read cmdline from user. Now 'just' video mode query, ext2 and ELF parsing are needed :D 2023-11-11 22:49:00 +02:00			`jmp stage2_main`
Bootloader: Start work on bootloader I wrote a fast first stage bootloader and a installer to put it into a disk image. 2023-11-09 22:42:47 +02:00
Bootloader: Split bootloader into multiple files This cleans up the code since bootloader is starting to near 1k lines 2023-11-14 03:26:03 +02:00			`.global print_and_halt`
Bootloader: Start work on bootloader I wrote a fast first stage bootloader and a installer to put it into a disk image. 2023-11-09 22:42:47 +02:00			`print_and_halt:`
			`call puts`
			`halt:`
			`hlt`
			`jmp halt`


			`#########################################`
			`#`
			`# STAGE 2 BOOTLOADER`
			`#`
			`#########################################`

			`.section .stage2`
Bootloader: Continue work on bootloader Bootloader can now get the memory map and read cmdline from user. Now 'just' video mode query, ext2 and ELF parsing are needed :D 2023-11-11 22:49:00 +02:00
Bootloader: Find root partition from GPT header 2023-11-13 18:55:48 +02:00			`stage2_main:`
			`# clear screen and enter 80x25 text mode`
			`movb $0x03, %al`
			`movb $0x00, %ah`
			`int $0x10`

			`# print hello message`
			`movw $hello_msg, %si`
			`call puts; call print_newline`

			`call get_memory_map`
Bootloader: Split bootloader into multiple files This cleans up the code since bootloader is starting to near 1k lines 2023-11-14 03:26:03 +02:00			`call read_user_command_line`
Bootloader: Find root partition from GPT header 2023-11-13 18:55:48 +02:00
			`call print_newline`

			`movw $start_kernel_load_msg, %si`
			`call puts; call print_newline`

			`call print_memory_map`

			`call find_root_disk`
			`call find_root_partition`

Bootloader: Split bootloader into multiple files This cleans up the code since bootloader is starting to near 1k lines 2023-11-14 03:26:03 +02:00			`call print_root_partition_info`
Bootloader: Implement basic ext2 filesystem This can search for files in an ext2 filesystem. Only 12 blocks are currently supported. Now only ELF loading is missing for loading the actual kernel! 2023-11-15 16:36:53 +02:00			`call print_newline`

			`call has_ext2_filesystem`
			`testb %al, %al`
			`jz print_and_halt`

			`call ext2_find_kernel`
Bootloader: Continue work on bootloader Bootloader can now get the memory map and read cmdline from user. Now 'just' video mode query, ext2 and ELF parsing are needed :D 2023-11-11 22:49:00 +02:00
			`jmp halt`
Bootloader: Start work on bootloader I wrote a fast first stage bootloader and a installer to put it into a disk image. 2023-11-09 22:42:47 +02:00
			`hello_msg:`
			`.asciz "This is banan-os bootloader"`

Bootloader: Continue work on bootloader Bootloader can now get the memory map and read cmdline from user. Now 'just' video mode query, ext2 and ELF parsing are needed :D 2023-11-11 22:49:00 +02:00			`start_kernel_load_msg:`
			`.asciz "Starting to load kernel"`