I want to get dimensions of hard drive. I find that I need to use int 13h with ah = 08h. I found on wikipedia that it returns following:
DH logical last index of heads = number_of - 1 (because index starts with 0)
CX [7:6] [15:8] logical last index of cylinders = number_of - 1 (because index starts with 0)
[5:0] logical last index of sectors per track = number_of (because index starts with 1)
The problem is that I have no idea how to read only bits [5:0] on it own to get last index of sector per track, and the same with [7:6][15:8] to get last index of cylinders. I would be really thankful if someone would point me into the right way or explain how to do this.
mov ax, cx
and ax, 63
shr cl, 6
xchg cl, ch
This leaves sectors in AX and cylinders in CX