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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;; Miguel's FoolOS Helper Functions ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;
;disk_load_16
;
[bits 16]
DISK_LOAD:
db "D",0
DISK_LOAD_ERROR
db "E",0
Head:
db 0
Track:
db 0
Sector:
db 1
LBA:
dw 0 ;; starts at zero!
Sectors:
dw 80
Heads:
dw 2
;disk_load routune (load dh sectors from drive dl to es:bx)
;lba mode has 52 sectors hardcoded!
disk_load_16:
pusha
;;; ; check if LBA is supported
;;; pusha
;;; mov ah,0x41
;;; mov bx,0x55aa
;;; int 0x13
;;; jnc disk_load_lba
;;; popa
disk_load_next:
call ESBX
; load using CHS
;; mov al,80 ;read dh sectors (amount)
;; mov cx,[LBA]
;; cmp cx,0
;; jne disk_read_normal
;; mov al,79 ;read dh sectors (amount)
;; disk_read_normal
mov al,1
mov cl,[Sector] ;sector
mov ch,[Track] ;cyl
mov dl,[BOOT_DRIVE]
mov dh,[Head] ;head
mov ah,0x02 ;BIOS read sector func
int 0x13 ;bios interrupt
jnc disk_read_ok ;ready becaue of error :(
mov bx, DISK_LOAD_ERROR
call print_string
jmp $
disk_read_ok:
mov ax,[LBA]
cmp ax,880
je disk_load_ready
mov bx, DISK_LOAD
call print_string
add ax,1 ;conver LBA to CHS
mov [LBA],ax
call LBACHS
jmp disk_load_next
disk_load_ready:
jmp $
popa
ret
ESBX:
xor dx,dx
xor dx,dx
mov ax,[LBA]
mov bx,0x200
mul bx
mov bx,ax
add dx,1
shl dx,12
mov es,dx
ret
; load using LBA
;;;disk_load_lba:
;;;
;;; popa
;;;
;;; xor ah,ah
;;; mov ah,0x42
;;; lea si,[lba_adr]
;;; int 0x13
;;; jc skip_print
;;; mov bx, DISK_LOAD
;;; call print_string
;;; skip_print:
;;;
;;; popa
;;; ret
;;;
LBACHS:
xor dx, dx ; prepare dx:ax for operation
div WORD [Sectors] ; divide by sectors per track
inc dl ; add 1 (obsolute sector formula)
mov BYTE [Sector], dl
xor dx, dx ; prepare dx:ax for operation
div WORD [Heads] ; mod by number of heads (Absolue head formula)
mov BYTE [Head], dl ; everything else was already done from the first formula
mov BYTE [Track], al ; not much else to do :)
ret
lba_adr:
dw 0x10 ; size of packet ( 16 byte)
dw 53 ; number of sectors to read
dw 0x0000 ; target addr. offset
dw 0x1000 ; target addr. sector
dd 1 ; first sector to read
dd 0 ;
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