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 al,[esp+15]
and al,1+2+4+8
mov bl,byte [hdid]
add al,bl
add al,128+64+32
out dx,al
inc edx
mov al,20h
out dx,al
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?
Thanks,
...Gomer
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