hvaalde@cs.vu.nl (Aalderen van Harold) (03/14/91)
Hi, Does any one of you has any information about: - the format of the MEMCNTRL (0x424L) system variable in TT/Mega STE atari seemed to have changed its meaning. - how can one set and unset the use of the cache in TT/Mega STE. (in a program) - finding END adress of the ROM-space. - the meaning of the system cookies set by TOS 1.6 and greater (_CPU _FPU _VDO _SWI _MCH) - the adresses of the control register of the 68882 FPU in TT and Mega STE Any information is appreciated thanks in advance Harold van Aalderen (hvaalde@cs.vu.nl) (email prefered)
csbrod@immd4.informatik.uni-erlangen.de (Claus Brod) (03/15/91)
hvaalde@cs.vu.nl (Aalderen van Harold) writes: >- how can one set and unset the use of the cache in TT/Mega STE. > (in a program) On the TT, you have to use the 68030's cache control register to switch the processor cache on and off. The MegaSTE has an external cache which is controlled by some other means; perhaps they used some of the free bits in the soundchip's I/O ports. >- finding END adress of the ROM-space. I've been looking for a solution for this problem for quite a while now. So far it seems that there is no legal way to find out the end of OS code. >- the meaning of the system cookies set by TOS 1.6 and greater > (_CPU _FPU _VDO _SWI _MCH) FPU: 1 for 68881, 2 for 68882 CPU: type of CPU (00, 10, 20, 30...) VDO: type of video hardware (higher word: major revision, lower word: minor revision) SWI: state of internal DIP switches MCH: kind of machine (Mega, STE, TT) >- the adresses of the control register of the 68882 FPU in TT > and Mega STE In the TT, you must use the FPU instructions. In an MegaSTE, the FPU registers should be mapped to the same locations as they were with those FPU add-on cards for standard Megas. ---------------------------------------------------------------------- Claus Brod, Am Felsenkeller 2, Things. Take. Time. D-8772 Marktheidenfeld, West Germany (Piet Hein) csbrod@medusa.informatik.uni-erlangen.de ----------------------------------------------------------------------