52 lines
784 B
NASM
52 lines
784 B
NASM
|
; Drive table
|
||
|
|
; Header:
|
||
|
|
; byte number of drives
|
||
|
|
; Item (type BIOS CHS):
|
||
|
|
; byte type (1)
|
||
|
|
; byte drive number
|
||
|
|
; word number of cylinders
|
||
|
|
; byte number of heads
|
||
|
|
; word number of sectors per cylinder
|
||
|
|
; 3 bytes padding
|
||
|
|
; Item (type BIOS LBA):
|
||
|
|
; byte type (2)
|
||
|
|
; byte drive number
|
||
|
|
; dword offset
|
||
|
|
; dword size
|
||
|
|
|
||
|
|
; Create a drive table at ES:DI
|
||
|
|
drvtab_create:
|
||
|
|
mov ax, 0x2B
|
||
|
|
call intr_register
|
||
|
|
|
||
|
|
mov al, 8 ; 8 drives per default
|
||
|
|
mov ah, 10 ; 10 bytes per drive
|
||
|
|
stosb
|
||
|
|
mul ah
|
||
|
|
|
||
|
|
xor cx, cx
|
||
|
|
xchg cx, ax
|
||
|
|
rep stosb
|
||
|
|
|
||
|
|
ret
|
||
|
|
|
||
|
|
; Get drive table item
|
||
|
|
; IN DL drive number (A=0, B=1, ...)
|
||
|
|
; OUT DS:SI ptr to drive struct
|
||
|
|
drvtab_load:
|
||
|
|
push ax
|
||
|
|
mov ax, 0x2B
|
||
|
|
call intr_load
|
||
|
|
cmp dl, [ds:si]
|
||
|
|
jnb .err
|
||
|
|
mov al, 10
|
||
|
|
mul dl
|
||
|
|
inc ax
|
||
|
|
add si, ax
|
||
|
|
pop ax
|
||
|
|
ret
|
||
|
|
.err:
|
||
|
|
pop ax
|
||
|
|
stc
|
||
|
|
ret
|