huynh@puff.UUCP (adventurer extraordinaire) (02/07/86)
Does anyone know of a way to access the HP9836U graphics memory using assembly? According to the manual, the memory resides from $530000 - $53xxxx. The problem that I had was that the O/S wouldnt let anything reference outside a predetermined address boundary. I tried to set the 68000 supervisor mode on but that didnt seem to be working Thanx mucho ------------------------------------------------------------------------------- Destination: puff.wisc.edu user:huynh in real-life: Michael Huynh
rml@hpfcla.UUCP (02/11/86)
> Does anyone know of a way to access the HP9836U graphics memory using > assembly? According to the manual, the memory resides from $530000 - $53xxxx. > The problem that I had was that the O/S wouldnt let anything reference outside > a predetermined address boundary. Those addresses are physical addresses. They are not mapped into the address space of user processes in HP-UX. The 5.1 release of HP-UX will include a driver (graphics(4)) which does just that. It is possible (but slow, and probably not useful) to access those addresses through /dev/mem. If you don't need UNIX/HP-UX, the Pascal Workstation system allows access of physical addresses. > I tried to set the 68000 supervisor mode on but that didnt seem to be working It's an important feature of the intruction set of any machine that code running in one protection mode cannot increase its privileges. Bob Lenk {hplabs, ihnp4}!hpfcla!rml