Download TMQ Vol V.ii - tim

Volume V.ii THE MISOSYS QUARTERLY - Winter 1990/1991
Volume Vii
extended banks and the standard upper
32K bank are maintained together, we
would no longer have to depend upon
separate code to process all the various
non-bank switching functions accessible
through the @BANK SVC. By testing for
bank number limits (above 10) at the start
of our new @BANK routine, we can also
eliminate the needfora$BAR table (Bank
Available RAM), and in fact use that 1byte freed space as the needed 1-byte
extension of the new BUR$. Of course
these patches also assume (and require)
that the user has both the standard 128K
expansion, and the 256K ofXLR8er RAM
available, otherwise these patches should
not be used. Considering the cheap price
of RAM chips, there is little reason why
you should not add the 128K expansion if
you do not have it. This combination of
the 128K and the 256K expansions gives
us total of 384K memory. This provides
us with 11 addressable banks (0 through
10), and our base 32K of memory, which
cannotbe addressed through the@BANK
SVC due to the fact that the computer's
operating system must always be resident.
Of the original "Houdé" patches, the alterations to SYSO/SYS are relatively
unchanged from his code, except for an
additional initialization routine to set up
our new BUR$ mask. I found no need to
change tasker patches or math enhancements. By default, the code is set up to 1
memory wait state, 11/0 wait state, and
the interval of refresh cycle set to 40.
However, I have mine boot up with an
interval of refresh cycle of 80 and have
experienced no problems at all (I am
using it on a Model 4D with an RS HiRes
board. Thus I must use a 6" ribbon for the
XLR8er, and have shielded the ribbon
with kitchen aluminum foil and masking
tape - otherwise the XLR8er would refuse to run without locking up. I have also
tested it on 2 of my other Model 4's and
my Model 4P). If you want to change the
patch for a refresh interval of 80, all you
need to do is change the 02 in the line
within the XLSYSOB1/FIX file beginning with D10,34= to 03 (12th data item
from the left).
The most obvious difference comes in the
patches to BOOT/SYS. Mainly, the bulk
of my patches center on relative sector 6,
over-writing the old @BANK routine code.
Inside TMQ
The 33 bytes of needed extended code
deal basically with 12 bytes to finish up
the new @BANK routine, and the remaining 21 bytes being the new @VDCTL
setup as written by M. Houdé, and simply
relocated into lower RAM. Being such a
short piece of patching, I did away with
the 9 byte header that M. Houde used, and
tacked these 33 bytes onto the end of the
-34-
$FD floppy disk driver.
As of this writing, I have been using these
new patches for over a month now, and
have absolutely no problem with them. I
make heavy useofmyXMEMDISK/DCT
ram disk driver, as well as BUSYCALC,
my yet to be released fast disk file backup
program, and my new BCX Business
Inside TMQ