I have 8-byte aligned,but it still show me the same error I occured.I cannot position where my error is,so does anyone know where the error?
Code: Select all
KERNEL_STACKSIZE equ 128*1024*1024
section .text
bits 64
header_start:
; magic number
dd 0xe85250d6
; architecture
dd 0
; header length
dd header_end-header_start
; checksum
dd 0x100000000 - (0xe85250d6 + 0 + (header_end - header_start))
align 8
framebuffer_tag:
dd 5 ; type
dd 20 ; size
dd 800 ; width
dd 600 ; height
dd 32 ; depth
align 8
framebuffer_tag_end:
align 8
bootinfo_request_tag:
dd 1 ; type
dd bootinfo_request_tag_end - bootinfo_request_tag ;size
dd 4 ; basic memory info
dd 1 ; boot command line
dd 8 ; framebuffer info
dd 12 ; efi64 system table pointer
align 8
bootinfo_request_tag_end:
align 8
framebuffer_info:
dd 8 ;type
dd framebuffer_info_end-framebuffer_info ;size
dq 256*1024*1024 ;framebuffer_address
dd 4 ;framebuffer_pitch
dd 800 ; framebuffer_width
dd 600 ; framebuffer_height
db 32 ;framebuffer bits per pixel
db 1 ;framebuffer type
db 0 ;reserved
db 0 ;red_field_position
db 1 ;red_mask_size
db 2 ;blue_field_position
db 1 ;blue_mask_size
db 1 ;green_field_position
db 1 ;green_mask_size
align 8
framebuffer_info_end:
; end tag
dd 0
dd 8
align 8
header_end:
bits 32
global start
start:
mov esp, stack_top
call check_multiboot
call check_cpuid
call check_long_mode
call setup_page_tables
call enable_paging
lgdt [gdt64.pointer]
jmp 0x8:long_mode_start
hlt
check_multiboot:
cmp eax, 0x36d76289
jne .no_multiboot
ret
.no_multiboot:
mov al, "M"
jmp error
check_cpuid:
pushfd
pop eax
mov ecx, eax
xor eax, 1 << 21
push eax
popfd
pushfd
pop eax
push ecx
popfd
cmp eax, ecx
je .no_cpuid
ret
.no_cpuid:
mov al, "C"
jmp error
check_long_mode:
mov eax, 0x80000000
cpuid
cmp eax, 0x80000001
jb .no_long_mode
mov eax, 0x80000001
cpuid
test edx, 1 << 29
jz .no_long_mode
ret
.no_long_mode:
mov al, "L"
jmp error
setup_page_tables:
mov eax, page_table_l3
or eax, 0b11 ; present, writable
mov [page_table_l4], eax
mov eax, page_table_l2
or eax, 0b11 ; present, writable
mov [page_table_l3], eax
mov ecx, 0 ; counter
.loop:
mov eax, 0x200000 ; 2MiB
mul ecx
or eax, 0b10000011 ; present, writable, huge page
mov [page_table_l2 + ecx * 8], eax
inc ecx ; increment counter
cmp ecx, 512 ; checks if the whole table is mapped
jne .loop ; if not, continue
ret
enable_paging:
; pass page table location to cpu
mov eax, page_table_l4
mov cr3, eax
; enable PAE
mov eax, cr4
or eax, 1 << 5
mov cr4, eax
; enable long mode
mov ecx, 0xC0000080
rdmsr
or eax, 1 << 8
wrmsr
; enable paging
mov eax, cr0
or eax, 1 << 31
mov cr0, eax
ret
error:
; print "ERR: X" where X is the error code
mov dword [0xb8000], 0x4f524f45
mov dword [0xb8004], 0x4f3a4f52
mov dword [0xb8008], 0x4f204f20
mov byte [0xb800a], al
hlt
bits 64
long_mode_start:
; load null into all data segment registers
mov ax, 0
mov ss, ax
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov rsp,KERNEL_STACK+KERNEL_STACKSIZE
extern kernel_main
call kernel_main
hlt
bits 32
section .bss
align 4096
page_table_l4:
resb 4096
page_table_l3:
resb 4096
page_table_l2:
resb 4096
stack_bottom:
resb 4096 * 4
stack_top:
bits 64
KERNEL_STACK:
resb KERNEL_STACKSIZE
bits 32
section .rodata
gdt64:
dq 0 ; zero entry
.code_segment: equ $ - gdt64
dq (1 << 43) | (1 << 44) | (1 << 47) | (1 << 53) ; code segment
.pointer:
dw $ - gdt64 - 1 ; length
dq gdt64 ; address
