Message board for the users of flat assembler.
> MenuetOS > Menuet HD Question
Below is a section of the code used to read info off of the HD. Same code for this part for both CHS and LBA access.
mov bl,byte [hdid]
My question is: Why is the top nyble 128+64+32? My understanding is this port has the following format:
; 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
Which would indicate bit 6(64 decimal) should be clear. What is the reason it is set in Menuetos?
|26 Jan 2004, 22:09||
Bitfields for hard disk controller drive/head specifier: Bit(s) Description (Table P084) 7 =1 6 LBA mode enabled, rather than default CHS mode 5 =1 4 drive select (0 = drive 0, 1 = drive 1) 3-0 head select bits (CHS mode)
|26 Jan 2004, 22:43||
|27 Jan 2004, 00:03||
< Last Thread | Next Thread >
Copyright © 1999-2020, Tomasz Grysztar.
Powered by rwasa.