您最多选择25个主题
主题必须以字母或数字开头，可以包含连字符 (-)，并且长度不得超过35个字符
333 行
8.2 KiB
333 行
8.2 KiB
ORG 0x7C00
|
|
BITS 16
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
; SLRboot
|
|
; Bootloader for SingOS
|
|
; version 0.2.0.3-exp
|
|
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
|
|
cli
|
|
jmp long 0x0000:start
|
|
|
|
start:
|
|
mov ax, 0x1000
|
|
mov ss, ax
|
|
mov sp, 0xb000
|
|
mov ax, 0
|
|
mov ds, ax
|
|
mov es, ax
|
|
mov [disk_identifier], dl
|
|
sti
|
|
mov si, 0x7c00
|
|
mov di, 0x600
|
|
mov cx, 0x100
|
|
rep movsw
|
|
mov bx, relocated
|
|
sub bx, 0x7600 ; Calculate the offset.
|
|
push bx
|
|
ret ; Return far
|
|
;jmp long 0:bx
|
|
|
|
relocated:
|
|
|
|
mov si, message ; Put address of the null-terminated string to output into 'si'
|
|
call print ; Call our string-printing routine
|
|
|
|
; Check for more than one active partition that we can start from.
|
|
xor bx, bx
|
|
xor cx, cx
|
|
mov ax, [partition_1.active_partition]
|
|
cmp ax, 0x80
|
|
jne check_p_2
|
|
mov bx, 0x01 ; Partion 1 active
|
|
inc cx
|
|
|
|
check_p_2:
|
|
mov ax, [partition_2.active_partition]
|
|
cmp ax, 0x80
|
|
jne check_p_3
|
|
inc cx
|
|
mov bx, 0x02 ; Partion 2 active
|
|
|
|
check_p_3:
|
|
mov ax, [partition_3.active_partition]
|
|
cmp ax, 0x80
|
|
jne check_p_4
|
|
inc cx
|
|
mov bx, 0x03 ; Partion 3 active
|
|
|
|
check_p_4:
|
|
mov ax, [partition_4.active_partition]
|
|
cmp ax, 0x80
|
|
jne eval_active_partion_number
|
|
inc cx
|
|
mov bx, 0x04 ; Partion 4 active
|
|
|
|
eval_active_partion_number:
|
|
cmp cx, 1
|
|
je boot_partition
|
|
; here goes wait call, for the user to enter debug mode.
|
|
; Wating for 2 seconds:
|
|
mov ah, 0x86 ; code for waiting interupt call
|
|
mov cx, 0x001e ; high count of microseconds
|
|
mov dx, 0x8480 ; low count
|
|
int 0x15
|
|
.busy_wait_for_key:
|
|
xor ax, ax
|
|
mov ah, 0x01 ; BIOS call to wait for key
|
|
int 0x16
|
|
|
|
|
|
boot_partition:
|
|
; IMPORTANT bx, has to hold the value 1-4 for the partiotion that wanted to be booted.
|
|
|
|
mov bx, 2
|
|
|
|
mov ax, partition_1
|
|
.loop:
|
|
cmp bx, 1
|
|
je break
|
|
add ax, 0x10
|
|
;call dumpax
|
|
dec bx
|
|
jmp .loop
|
|
break:
|
|
|
|
add ax, 8 ; This is the offset to fetch the LBA start adress of the partition record
|
|
mov bx, ax
|
|
xor ax, ax
|
|
mov ax, [bx] ; first part of LBA
|
|
mov WORD [DAPACK.lba_addr_dw_low], ax
|
|
call dumpax
|
|
add bx, 2 ; next part
|
|
mov ax, [bx]
|
|
mov WORD [DAPACK.lba_addr_dw_low + 1], ax
|
|
call dumpax
|
|
|
|
mov WORD [DAPACK.blkcnt], 0x01
|
|
mov WORD [DAPACK.db_addr_segment], 0x0000
|
|
mov WORD [DAPACK.db_addr_offset], 0x7c00
|
|
mov si, DAPACK ; address of "disk address packet"
|
|
xor ax, ax
|
|
mov ah, 0x42 ; READ
|
|
mov dl, [disk_identifier]
|
|
int 0x13
|
|
|
|
jmp long 0x0:0x7c00
|
|
|
|
cli
|
|
hlt
|
|
|
|
|
|
%IF 0
|
|
cli
|
|
jmp long 0x0000:start
|
|
|
|
start:
|
|
xor ax, ax
|
|
mov ds, ax
|
|
mov es, ax
|
|
mov ss, ax
|
|
mov [disk_identifier], dl
|
|
|
|
; initialize stack
|
|
; Set up 4K stack after this bootloader
|
|
; [Remember: Effective Address = Segment*16 + Offset]
|
|
mov ax, 0x7C0 ; Set 'ax' equal to the location of this bootloader divided by 16
|
|
add ax, 0x20 ; Skip over the size of the bootloader divided by 16
|
|
mov ss, ax ; Set 'ss' to this location (the beginning of our stack region)
|
|
mov sp, 8192 ; Set 'ss:sp' to the top of our 8K stack
|
|
sti
|
|
mov si, message ; Put address of the null-terminated string to output into 'si'
|
|
call print ; Call our string-printing routine
|
|
|
|
mov si, enter_debug_mode
|
|
call print
|
|
call printCRLF
|
|
;%IF 0
|
|
; here goes wait call, for the user to enter debug mode.
|
|
; Wating for 2 seconds:
|
|
mov ah, 0x86 ; code for waiting interupt call
|
|
mov cx, 0x001e ; high count of microseconds
|
|
mov dx, 0x8480 ; low count
|
|
int 0x15
|
|
|
|
.busy_wait_for_key:
|
|
xor ax, ax
|
|
mov ah, 0x01 ; BIOS call to wait for key
|
|
int 0x16
|
|
jnz debug_mode
|
|
|
|
; entering system check:
|
|
mov si, enter_system_check
|
|
|
|
mov si, sys_check_ok ; Put address of the null-terminated string to output into 'si'
|
|
call print ; Call our string-printing routine
|
|
|
|
mov si, boot_system ; Put address of the null-terminated string to output into 'si'
|
|
call print ; Call our string-printing routine
|
|
|
|
;This goes first as to now overwrite %ah and %al.
|
|
;mov ax, 0x0050
|
|
;mov es, ax ;Section to write into
|
|
;mov ah, 0x2 ;Read sectors from drive
|
|
;mov al, 0x08 ;Number of sectors to read (31 * 512 = 15872 bytes)
|
|
;mov ch, 0x0 ;Low 8 bits of cylinder
|
|
;mov cl, 0x11 ;First sector to read (bits 0-5), upper bits of cylinder (bits 6-7)
|
|
;mov dh, 0x0 ;Head number
|
|
;mov dl, [disk_identifier] ;Drive number
|
|
;mov bx, 0x0000 ;Offset into section
|
|
;int 0x13 ;Low level disk services
|
|
|
|
;jnc notcarry
|
|
;mov si, error_str
|
|
;call print
|
|
;jmp endcarrycheck
|
|
|
|
notcarry:
|
|
;mov si, success_str
|
|
;call print
|
|
;call printCRLF
|
|
|
|
mov ax, 0x0
|
|
mov ds, ax
|
|
mov ax, 89 ; lba adress
|
|
|
|
jmp 0x50:0x0000 ; Jump to the kernel
|
|
|
|
endcarrycheck:
|
|
cli ; Clear the Interrupt Flag (disable external interrupts)
|
|
hlt ; Halt the CPU (until the next external interrupt)
|
|
|
|
debug_mode:
|
|
mov si, .welcome_debug
|
|
call print
|
|
cli ; Clear the Interrupt Flag (disable external interrupts)
|
|
hlt
|
|
|
|
.welcome_debug db 'This is debug mode', 0
|
|
|
|
printCRLF:
|
|
mov ah, 0xE
|
|
mov al, 13
|
|
int 0x10
|
|
mov al, 10
|
|
int 0x10
|
|
ret
|
|
%ENDIF
|
|
|
|
;Routine for printing a 'ax' as hex
|
|
dumpax:
|
|
pusha ; save registers
|
|
mov bx, ax
|
|
mov ah, 0xE ; Teletype output
|
|
|
|
mov cx, 4 ; 4 nipples in a 16 bit word
|
|
.loop:
|
|
rol bx, 4 ; rotate to next nipple
|
|
mov al, bl ; we copy to al because we need to mask only the low 4 bits
|
|
and al, 1111b ; Do the masking
|
|
add al, '0' ; convert to ASCII
|
|
cmp al, '9' ; If we are greater than 9 ascii, we add 7 to make digit 10 be represented as 'A'
|
|
jbe .skip ; -|-
|
|
add al, 7 ; -|-
|
|
.skip: ; -|-
|
|
int 0x10 ; BIOS call 'output'
|
|
loop .loop
|
|
|
|
popa ; restore registers
|
|
ret
|
|
|
|
; Routine for outputting string in 'si' register to screen
|
|
print:
|
|
mov ah, 0xE ; Specify 'int 0x10' 'teletype output' function
|
|
; [AL = Character, BH = Page Number, BL = Colour (in graphics mode)]
|
|
.printchar:
|
|
lodsb ; Load byte at address SI into AL, and increment SI
|
|
cmp al, 0
|
|
je .done ; If the character is zero (NUL), stop writing the string
|
|
int 0x10 ; Otherwise, print the character via 'int 0x10'
|
|
jmp .printchar ; Repeat for the next character
|
|
.done:
|
|
ret
|
|
|
|
data:
|
|
message db 'SLRboot for SingOS! v0.2.0.3-exp',13,10,0
|
|
;enter_debug_mode db 'Press d to enter bootloader debug mode',13,10,0
|
|
;enter_system_check db 'Performing system check:',13,10,0
|
|
;sys_check_ok db 'System check ok', 13, 10, 0
|
|
;boot_system db 'Read SingOS from disk', 13, 10, 0
|
|
;error_str db 'Error', 0
|
|
;success_str db 'Success', 0
|
|
boot_this_partition: dw 0
|
|
disk_identifier db 0
|
|
|
|
|
|
DAPACK:
|
|
.dap_Size: db 0x10 ; This is always 16 bytes (0x10)
|
|
.rev_byte: db 0x0 ; reserved byte, should always be zero
|
|
.blkcnt: dw 0x0 ; int 13 resets this to # of blocks actually read/written
|
|
.db_addr_offset: dw 0x0 ; memory buffer destination address (0:7c00)
|
|
.db_addr_segment: dw 0x0 ; in memory page zero
|
|
.lba_addr_dw_low: dd 0x0 ; put the lba to read in this spot
|
|
.lba_addr_dw_high: dd 0x0 ; more storage bytes only for big lba's ( > 4 bytes )
|
|
|
|
|
|
; Pad to 510 bytes (boot sector size minus 2) with 0s, and finish with the two-byte standard boot signature
|
|
times 446-($-$$) db 0 ; First partion entry
|
|
partition_1:
|
|
.active_partition db 0x80
|
|
.start_CHS db 0x00, 0x00, 0x11;0x20, 0x21, 0x00
|
|
.disk_type db 0x83
|
|
.end_CHS db 0x8C, 0x3D, 0x0F
|
|
.start_LBA db 0x10, 0x00, 0x00, 0x00
|
|
.size db 0x00, 0xC8, 0x03, 0x00
|
|
|
|
partition_2:
|
|
.active_partition db 0x80
|
|
.start_CHS db 0x8C, 0x3E, 0x0F
|
|
.disk_type db 0x83
|
|
.end_CHS db 0xFF, 0xFF, 0xFF
|
|
.start_LBA db 0x00, 0xD0, 0x03, 0x00
|
|
.size db 0x00, 0x28, 0x1C, 0x03
|
|
|
|
partition_3:
|
|
.active_partition db 0x00
|
|
.start_CHS db 0x00, 0x00, 0x00
|
|
.disk_type db 0x00
|
|
.end_CHS db 0x00, 0x00, 0x00
|
|
.start_LBA db 0x00, 0x00, 0x00, 0x00
|
|
.size db 0x00, 0x00, 0x00, 0x00
|
|
|
|
partition_4:
|
|
.active_partition db 0x00
|
|
.start_CHS db 0x00, 0x00, 0x00
|
|
.disk_type db 0x00
|
|
.end_CHS db 0x00, 0x00, 0x00
|
|
.start_LBA db 0x00, 0x00, 0x00, 0x00
|
|
.size db 0x00, 0x00, 0x00, 0x00
|
|
|
|
times 510-($-$$) db 0
|
|
dw 0xAA55 ; => 0x55 0xAA (little endian byte order)
|
|
; bootloder debug_mode goes here
|
|
|
|
times 8192-($-$$) db 0
|
|
|
|
|
|
|
|
; mov si, 0x7be
|
|
; cmp byte [si], al
|
|
; jne 0x33
|
|
; add si, 0x10
|
|
; cmp si, 0x7fe
|
|
; jne 0x24
|
|
; jmp 0x49
|
|
; mov ah, 2
|
|
; mov al, 1
|
|
; mov bx, 0x7c00
|
|
; mov dl, 0x80
|
|
; mov dh, byte [si + 1]
|
|
; mov cx, word [si + 2]
|
|
; int 0x13
|
|
; jmp long 0:0x7c00
|
|
|
|
; jmp 0x49
|