[comp.sys.apple2] safe Zero Page locations

ST6934@SIUCVMB.BITNET (11/13/90)

>Date:         Mon, 12 Nov 90 18:20:53 GMT
>From:         Andy Tefft <psuvm!art100@PSUVAX1.CS.PSU.EDU>
>Subject:      safe 0-page addresses

>I can never keep track of what 0-page addresses are used by
>what program and I need about 7 of them (3 pairs plus one)
>that won't be used by applesoft, basic.system, or prodos.
>Does anyone have any 0-page maps (with actual meanings
>rather than just saying which ones are used)? I only have
>monitor locations now.


From the Apple II Prodos Technical Reference manual:

Appendix A-4:Zero Page-
"Figure A-3 is a memory map that shows the locations by the
Monitor, Applesoft, the Device Drivers, and the ProDOS MLI.
The owner of each location is shown by a letter: M,A,D, or P."

Figure A-3. Zero Page Memory Map
____________________________________________________________________________
Use by the Monitor (M), Applesoft (A), Disk Drivers (D), and the ProDOS MLI
(P) is shown.

Decimal---0   1   2   3   4   5   6   7   8   9   0   11   12   13   14   15
,   Hex---$0  $1  $2  $3  $4  $5  $6  $7  $8  $9  $A  $B   $C   $D   $E   $F
----------------------------------------------------------------------------
0   $00 | DA  DA  A   A   A   A                    A   A    A    A    A    A
16  $10 |  A   A  A   A   A   A   A   A   A   A?   A?  A?   A?   A?       *M
32  $20 |  M   M  M   M   M   M   A?M A?M M   M    M   M    A?M  A?M  M  A?M
48  $30 |  A?M M  A?M A?M M   M   M   M   M   M  PMD PMD A?PMD A?PMD A?PMDA?DM
64  $40 | PMD PMD PMD PMD PMD PMD PMD PM PM  PM    P   P    P    P    PM   M
80  $50 |  MA  MA  MA  MA  MA  MA  A   A  A   A    A   A    A    A    A    A
96  $60 |  A   A   A   A   A   A   A   A  A   A    A   A    A    A    A    A
112 $70 |  A   A   A   A   A   A   A   A  A   A    A   A    A    A    A    A
128 $80 |  A   A   A   A   A   A   A   A  A   A    A   A    A    A    A    A
144 $90 |  A   A   A   A   A   A   A   A  A   A    A   A    A    A    A    A
160 $A0 |  A   A   A   A   A   A   A   A  A   A    A   A    A    A    A    A
176 $B0 |  A   A   A   A   A   A   A   A  A   A    A   A    A    A    A    A
192 $C0 |  A   A   A   A   A   A   A   A  A   A    A   A    A    A
208 $D0 |  A   A   A   A   A   A   A?     A   A    A   A    A    A    A    A
224 $E0 |  A   A   A       A   A   A   A  A   A    A
240 $F0 |  A   A   A   A   A   A   A   A  A   A                           A?

* Byte used in original Apple IIe ROMs, now free.
? Discrepency between ProDOS Technical Reference Manual and the Apple IIe
                      ---------------------------------         ---------
Technical Reference Manual.  Published by Addison-Wesley Publishing Company
--------------------------   Copyright 1986 Apple Computer Inc.