Topic       : The ATARI Compendium
Author      : Scott Sanders / JAY Software
Version     : 1.25 (20/6/2003)
Subject     : Documentation
Nodes       : 1117
Index Size  : 32614
HCP-Version : 6
Compiled on : Atari
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                             User/Supervisor Mode


The XBIOS call Supexec() provides access to a special mode of the 680x0
processor called supervisor mode. Normal programs always execute in user
mode. Programs operating in user mode, however, have less memory access
privileges than those operating in supervisor mode.

Some special instructions of the 680x0 may only be executed in supervisor
mode. In addition, any memory reads or writes to locations $0-$7FF or
memory-mapped I/O must be made in supervisor mode.

To use Supexec(), simply pass it the address of a function to be called.
When writing the function in 'C', you should be careful to define the
function in a way that is safe for your compiler (see your compiler
documentation for details).

While in supervisor mode, the AES should never be called.