🚀 go-pugleaf

Perhaps the most confusing point about your posting is calling a LINE A
*exception* a *TRAP* call.  All 680x0 boxes have *TRAP* vectors staring at
HEX $50.  The ST actually uses LINE F for GEM calls, and LINE A for low
level screen BLT routines.

Of course, Motorola specificaaly reserved LINE F for math calls in the 68881
I believe.

But teh original intent of your message, in other words, document location and
a method for returning and changing these locations, would be a nice touch.
I believe tho, if you pass an illegal function number to one of the trap
handlers (1, 13, 14) you get a pointer to the function table in A0.  This is
not documented that I know of, and is more or less a side-effect of passing
an illegal function number.  Of course, it is trivial at this point to get
a pointer to the desired routine, but nothing is standardized then.

- mike

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