help with some math

[earlz]

I need some help with a bit of math, i just really dont know where to start in the eqaution
i want to convert lba to chs
here is the only formula i could find but it is for chs to lba

Code: Select all

DOS_sector_num = BIOS_sector_num - 1 + Head_num*Sectors_per_track
		+ Track_num*Sectors_per_track*Total_heads

if anyone could help me it would greatly be appreciated

[Osbios]

This is my code for 1440KB floppys:

Code: Select all

;LBA2CHS
;C=LBA/36
;H=(LBA mod 36)/18
;S=((LBA mod 36)mod 18)+1
 mov eax,[LBA] ;eax=LBA(0..2879)
 xor edx,edx
 mov ecx,36
 div ecx
 mov [floppy_c],al
 mov eax,edx
 mov ecx,18
 div cl
 mov [floppy_h],al
 inc ah
 mov [floppy_s],ah

But this is only for 1440KB floppys!!!

[earlz]

thanks a lot, couldnt it be made for anyting if u change some values to the spt and tph and heads per drive

too bad i cant use this right now though(decided to switch to pmode so im not even close to fdd stuff yet)

edit:
(i mean i just decided to switch to pmode last night, about 3 hours after posting this)

[Osbios]

I found a good explanation:http://www.all-science-fair-projects.co ... conversion

[earlz]

thanks, looks promising