System Monitors / Freezer
There are a lot of pure software freezers out there. The usage of such tools may
be a great help on developing and debuging Slaves and the installed program.
Directly supported by WHDLoad is HrtMon 2.1 and ThrillKill 1.04. Other kinds may
be used via the option NoTrapHandler/S
(this has some other disadvantages of course). If you want direct support for an
other one, you can contact me and if it can be done I will include support for
it. On the startup of WHDLoad it will check if one of the supported monitors are
active. If one is found WHDLoad will do some special stuff. If the MMU is used
by WHDLoad it will declare the memory used by the monitor as valid and
WriteTrough cacheable. During the game/demo runs it will forward all NMI
exceptions to the NMI vector saved from the monitors vector table. Additional,
if the VBR is moved by WHDLoad (NoVBRMove/S is
not set and the cpu is at least a 68010) it will compare the "FreezeKey" with the actual keyboard value at each
interrupt. If the values matchs WHDLoad will do the required keyboard stuff,
transform the stackframe to a NMI stackframe and enter the monitor via his NMI
handler.
HrtMon
The detection in memory should be relative sure. I think it will also work with
future versions. Be careful if the MMU is used by whdload: dont access area
outside BaseMem from HrtMon. It will crash because HrtMon does not handle the
resulting Access Fault Exception. (tested with 2.1Demo)
ThrillKill
There is no useable signature in the freezer, so some code compares are used.
Therefore the detection will not work with other versions. (Contact me if you
have problems) (tested with 1.04Demo)