Files
blankos/src/kernel/loader.s
2024-08-26 12:57:51 +02:00

217 lines
2.8 KiB
ArmAsm

; Kernel loader assembly stub and multiboot2 header
; Author: xamidev
; Licensed under the Unlicense. See the repo below.
; https://github.com/xamidev/blankos
global loader
section .multiboot_header
mb_start:
align 8
; ASM macros
MAGIC_NUMBER equ 0xe85250d6 ; multiboot2 magic
FLAGS equ 0x0 ; 32-bit protected mode for i386
HEADER_LEN equ mb_end-mb_start
CHECKSUM equ -(MAGIC_NUMBER + FLAGS + HEADER_LEN)
; Multiboot 2 header, according to specification (16bytes)
dd MAGIC_NUMBER ; dd = 4 bytes = 32bits = u32
dd FLAGS
dd HEADER_LEN
dd CHECKSUM
; Tags? (28bytes)
; Tag 1 : set graphics mode (only recommended, can be overriden by GRUB)
align 8
dw 5 ; 2
dw 0 ; 2
dd 20 ; 4
dd 1920 ; 4
dd 1080 ; 4
dd 32 ; 4
; End of tags
align 8
dw 0 ; 2
dw 0 ; 2
dd 8 ; 4
; End of Multiboot 2 header
mb_end:
section .text:
KERNEL_STACK_SIZE equ 4096
extern kmain
loader:
cli
push ebx
call kmain
.loop:
jmp .loop
global gdt_flush
extern gp
gdt_flush:
lgdt [gp]
mov ax, 0x10
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ss, ax
jmp 0x08:flush2
flush2:
ret
global idt_load
extern idtp
idt_load:
lidt [idtp]
ret
%macro ISR_NOERRCODE 1
global isr%1
isr%1:
cli
push byte 0
push byte %1
jmp isr_common_stub
%endmacro
%macro ISR_ERRCODE 1
global isr%1
isr%1:
cli
push byte %1
jmp isr_common_stub
%endmacro
ISR_NOERRCODE 0
ISR_NOERRCODE 1
ISR_NOERRCODE 2
ISR_NOERRCODE 3
ISR_NOERRCODE 4
ISR_NOERRCODE 5
ISR_NOERRCODE 6
ISR_NOERRCODE 7
ISR_ERRCODE 8
ISR_NOERRCODE 9
ISR_ERRCODE 10
ISR_ERRCODE 11
ISR_ERRCODE 12
ISR_ERRCODE 13
ISR_ERRCODE 14
ISR_NOERRCODE 15
ISR_NOERRCODE 16
ISR_NOERRCODE 17
ISR_NOERRCODE 18
ISR_NOERRCODE 19
ISR_NOERRCODE 20
ISR_NOERRCODE 21
ISR_NOERRCODE 22
ISR_NOERRCODE 23
ISR_NOERRCODE 24
ISR_NOERRCODE 25
ISR_NOERRCODE 26
ISR_NOERRCODE 27
ISR_NOERRCODE 28
ISR_NOERRCODE 29
ISR_NOERRCODE 30
ISR_NOERRCODE 31
extern fault_handler
isr_common_stub:
pusha
push ds
push es
push fs
push gs
mov ax, 0x10
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov eax, esp
push eax
mov eax, fault_handler
call eax
pop eax
pop gs
pop fs
pop es
pop ds
popa
add esp, 8
iret
%macro IRQ 2
global irq%1
irq%1:
cli
push byte 0
push byte %2
jmp irq_common_stub
%endmacro
IRQ 0, 32
IRQ 1, 33
IRQ 2, 34
IRQ 3, 35
IRQ 4, 36
IRQ 5, 37
IRQ 6, 38
IRQ 7, 39
IRQ 8, 40
IRQ 9, 41
IRQ 10, 42
IRQ 11, 43
IRQ 12, 44
IRQ 13, 45
IRQ 14, 46
IRQ 15, 47
extern irq_handler
irq_common_stub:
pusha
push ds
push es
push fs
push gs
mov ax, 0x10
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov eax, esp
push eax
mov eax, irq_handler
call eax
pop eax
pop gs
pop fs
pop es
pop ds
popa
add esp, 8
iret
section .bss
align 4
kernel_stack:
resb KERNEL_STACK_SIZE
mov esp, kernel_stack + KERNEL_STACK_SIZE