On C64, VIC-20 and Plus/4, the conio library PLOT routine uses direct
calls into the Kernal, including the Kernal PLOT routine that we're
replacing. These were previously hardcoded addresses; we change these
to use the symbols for those routines defined in cbm_kernal.inc. (This
changes no functionality.)
To do this, we need to import cbm_kernal.inc in a namespace so we
don't have a collision between the PLOT that we're defining and the
Kernal definition.
We also add a UPDCRAMPTR symbol (used by kplot for VIC-20 and C64) to
the direct entry kernal routines in in cbm_kernal.inc, and expand the
comments describing what the "direct entry" Kernal routines are.
<greg.king5@verizon.net> (GitHub: greg-king5) came up with this idea
and did initial testing of it.
This has been tested on VICE xvic, x64 and xplus4 emulators with a
program that does a cputs() call (github.com/0cjs/vic20cc65) to
confirm that it works the same way after as it did before.
for the VIC20: PLOT is not an kernal entry but a library function that will
do the right stuff. This makes it work with other stuff that calls PLOT, too.
git-svn-id: svn://svn.cc65.org/cc65/trunk@4249 b7a2c559-68d2-44c3-8de9-860c34a00d81
