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Clean up - and correct detection handling of multiple active partitions

master
Rhodez-x 5 anni fa
parent
commit
b45ac1b6ca
2 ha cambiato i file con 30 aggiunte e 129 eliminazioni
  1. BIN
      slrboot.bin
  2. +30
    -129
      slrboot.nasm

BIN
slrboot.bin Vedi File


+ 30
- 129
slrboot.nasm Vedi File

@ -3,7 +3,7 @@ BITS 16
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; SLRboot
; Bootloader for SingOS
; version 0.2.0.3-exp
; version 0.2.1.0-exp
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
cli
jmp long 0x0000:start
@ -36,34 +36,36 @@ call print ; Call our string-printing routine
xor bx, bx
xor cx, cx
mov ax, [partition_1.active_partition]
cmp ax, 0x80
cmp al, 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
cmp al, 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
cmp al, 0x80
jne check_p_4
inc cx
mov bx, 0x03 ; Partion 3 active
check_p_4:
mov ax, [partition_4.active_partition]
mov al, [partition_4.active_partition]
cmp ax, 0x80
jne eval_active_partion_number
inc cx
mov bx, 0x04 ; Partion 4 active
cli
hlt
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:
@ -76,18 +78,14 @@ 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:
@ -102,7 +100,6 @@ 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
@ -112,109 +109,28 @@ mov ah, 0x42 ; READ
mov dl, [disk_identifier]
int 0x13
jc endcarrycheck ; An error ocurred when reading from disk.
; If no error then jump to volume boot record
notcarry:
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
; If we did not suceed to read from disk
endcarrycheck:
mov si, error_str
call print
cli ; Clear the Interrupt Flag (disable external interrupts)
hlt ; Halt the CPU (until the next external interrupt)
debug_mode:
mov si, .welcome_debug
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
@ -237,6 +153,14 @@ loop .loop
popa ; restore registers
ret
printCRLF:
mov ah, 0xE
mov al, 13
int 0x10
mov al, 10
int 0x10
ret
; Routine for outputting string in 'si' register to screen
print:
mov ah, 0xE ; Specify 'int 0x10' 'teletype output' function
@ -251,13 +175,10 @@ jmp .printchar ; Repeat for the next character
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
message db 'SLRboot for SingOS! v0.2.1.0-exp',13,10,0
enter_debug_mode db 'Press d to enter bootloader debug mode',13,10,0
welcome_debug db 'Debug mode v.0.0.1:',13,10,0
error_str db 'Error', 0
boot_this_partition: dw 0
disk_identifier db 0
@ -283,7 +204,7 @@ partition_1:
.size db 0x00, 0xC8, 0x03, 0x00
partition_2:
.active_partition db 0x80
.active_partition db 0x00
.start_CHS db 0x8C, 0x3E, 0x0F
.disk_type db 0x83
.end_CHS db 0xFF, 0xFF, 0xFF
@ -310,24 +231,4 @@ 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
times 8192-($-$$) db 0

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