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os-k/boot/loader/io/ata.asm

139 lines
6.0 KiB
NASM

;=----------------------------------------------------------------------------=;
; GNU GPL OS/K ;
; ;
; Authors: spectral` ;
; NeoX ;
; ;
; Desc: Basic Read Only ATA Long mode Driver ;
; (x86_64 architecture only) ;
;=----------------------------------------------------------------------------=;
[BITS 64]
;; BPB
%define OEMName bp+0x03 ; Disk label
%define bytesPerSector bp+0x0b ; Bytes per sector
%define sectorsPerCluster bp+0x0d ; Sectors per cluster
%define reservedSectors bp+0x0e ; Reserved sectors
%define fats bp+0x10 ; Number of fats
%define rootDirEntries bp+0x11 ; Number of entries in root dir
%define sectors bp+0x13 ; Logical sectors
%define mediaType bp+0x15 ; Media descriptor byte
%define fatSectors bp+0x16 ; Sectors per FAT
%define sectorsPerTrack bp+0x18 ; Sectors per track
%define heads bp+0x1a ; Number of sides/heads
%define hiddenSectors bp+0x1c ; Hidden sectors
%define hugeSectors bp+0x20 ; LBA sectors
%define biosBootdrvNum bp+0x24 ; Bootdrv number
%define reserved bp+0x25 ; This is not used
%define bootSignature bp+0x26 ; Bootdrv signature
%define volumeId bp+0x27 ; Volume ID
%define volumeLabel bp+0x2b ; Volume Label
%define fatTypeLabel bp+0x36 ; File system type
;; GLOBAL DATA
Bootdrv db 0
end db "[End of Sector]", 0x0
buffer: times 513 db "_"
;; TEXT
ata_read:
;-----------------------------------------------------------------------;
; x64/LM ATA Reading function ;
; ;
; ;
;-----------------------------------------------------------------------;
; Technical infos about the ports (Intel Doc):
;
; Port Access Mode Misc
;
; 1f0 r/w Data register, the bytes of the disk itself
; 1f1 r Error register that can be handled
; 1f2 r/w Sector count, how many sectors to read
; 1f3 r/w Sector number, the actual sector wanted
; 1f4 r/w Cylinder low, cylinders is 0-1024
; 1f5 r/w Cylinder high, this makes up the rest of the 1024
; 1f6 r/w Drive/head
; bit 7 = 1
; bit 6 = 0
; bit 5 = 1
; bit 4 = 0 drive 0 select
; = 1 drive 1 select
; bit 3-0 head select bits
; 1f7 r Status register
; bit 7 = 1 controller is executing a command
; bit 6 = 1 drive is ready
; bit 5 = 1 write fault
; bit 4 = 1 seek complete
; bit 3 = 1 sector buffer requires servicing
; bit 2 = 1 disk data read corrected
; bit 1 = 1 index - set to 1 each revolution
; bit 0 = 1 previous command ended in an error
; 1f7 w Command register
; commands:
; 50h format track
; 20h read sectors with retry
; 21h read sectors without retry
; 22h read long with retry
; 23h read long without retry
; 30h write sectors with retry
; 31h write sectors without retry
; 32h write long with retry
; 33h write long without retry
;
push rax
push rbx
push rdx
push rcx
push rdi
mov dx, 0x1f6 ; Drive and head port
mov al, 0x0a0 ; Drive 0, head 0
out dx,al
mov dx, 0x1f2 ; Sector count port
mov al, 1 ; Read one sector
out dx, al
mov dx, 0x1f3 ; Sector number port
mov al, 1 ; Read sector one
out dx, al
mov dx, 0x1f4 ; Cylinder low port
mov al, 0 ; Cylinder 0
out dx, al
mov dx, 0x1f5 ; Cylinder high port
mov al, 0 ; The rest of the cylinder 0
out dx, al
mov dx, 0x1f7 ; Command port
mov al, 0x20 ; Read with retry.
out dx, al
still_going:
in al, dx
test al, 8 ; This means the sector buffer requires
;servicing.
jz still_going ; Don't continue until the sector buffer
;is ready.
mov cx, 512/2 ; One sector /2 because it copies words
mov rdi, buffer
mov dx, 0x1f0 ; Data port - data comes in and out of here.
rep insw
pop rdi
pop rcx
pop rdx
pop rbx
pop rax
mov bl, 0x0F
mov esi, buffer
call dump
mov bl, 0x0A
mov esi, end
call write
ret