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BIOS interrupt initalization
Posted: Tue Aug 19, 2003 4:24 am
by eliscool
Could someone please tell me what all the registers are initailized to but the BIOS (for your bootsector)? like DX is highbyte = ??h, lowbyte = drive num we booted from right? im pretty sure CS, DS and SS are set to 00h, but what is SP set to? is it 'valid' memory?
Re:BIOS interrupt initalization
Posted: Tue Aug 19, 2003 7:50 am
by Pype.Clicker
don't be sure of CS and DS : they could be 0x7C0 on some BIOSes.
SS:SP is "guaranteed to be some valid stack " (big enough to handle BIOS interrupts, imho) but you have no guarantee of how big it is, thus if you have function calls, you should better set up a new stack.
Re:BIOS interrupt initalization
Posted: Wed Aug 20, 2003 4:11 am
by eliscool
any of the other registers have useful stuff in them? (eg. like dl has the drive num)
Re:BIOS interrupt initalization
Posted: Wed Aug 20, 2003 4:38 am
by Pype.Clicker
not to my knowledge