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In a message dated 20-Jul-98 15:56:16 James Youngman <JYoungman@vggas.com> wrote: >>>>>> "ts" == Tomaz Stih <firstname.lastname@example.org> writes: ts>> When dealing with 68000 boards with no vector base register ts>> there is a problem with setting vectors because it is common ts>> to put ROM at 0x0000 address where vectors reside thus making ts>> it impossible to change them. >00000000 does not have to be ROM. You just have to be able to load 8 >bytes from it at reset time. I've seen boards by Pro-Active Control >which use a counter to change the memory mapping after the right >number of bus cycles to that the vectors can be in RAM (except, >effectively, the reset vector). An "interesting" note might be that (M68K) Amiga-computers has RAM at address 0, still they do bootstrap from ROM ;-} I don't know *how* the hardware (RAM/ROM switch) is implemented, though. ,-. ,-. / \ / \ / \ /Hannu E K Nevalainen ,-. ' www.it.kth.se/~henk \ / `-* _ // 1985+ `-' `-' \X/Amiga user Personal rc5-stats: 6,717 2^28-key blks, i.e. 1,803,080+ Mkeys, M68K Amiga. -- The complete Amiga memory map: AbsExecBase == 4L