Alto
Hardware
Manual
APPENDIX
B·
STANDARD
RESERVED
MEMORY
LOCATIONS
All
numbers are in octal.
Location
Page
0:
0-17
Page 1:
400-412
420
421
422
423
424
425.
426
427
430
431-450
452
453
457
460-477
500
501-517
521
522
523
524
525
527
530-567
570-577
600
601
602
603
604
605
606
607
610
611-612
613
614
615
616
617
620
621
DASTART
ITQUAN
ITBITS
MOUSEX
MOUSEY
CURSORX
CURSORY
RTC
CURMAP
WW
ACTIVE
MASKTAB
PCLOC
INTVEC
KBLK
KSTAT
KADDR
ITTIME
TRAPPC
TRAPVEC
EPLOC
EBLOC
EELOC
ELLOC
EICLOC
EIPLOC
EOCLOC
EOPLOC
EHLOC
DCBR
KNMAR
DWA
CBA
PC
SAD
Contents
Set
to
77400B
by
OS
(Swat)
Used by standard bootstrap operation
Display list header
(Std. Microcode)
Display vertical field interrupt bitword
(Std. Microcode)
Interval timer stored quantity
(Std. Microcode)
Interval timer bitword
(Std.
MIcrocode)
Mouse
X coordinate IStd. Microcodel
Mouse
Y coordinate
Std.
Microcode
Cursor
X coordinate Std. Microcode
Cursor
Y coordinate
Std.
Microcode
Real Time Clock
(Std. Microcode)
Cursor bitmap
(Std. Microcode)
Interru:pt wakeups
waitin~(Std.
Microcode)
Active
mterrupt bitword
Std.
Microcode)
Zero (Extension
of
MAS
TAB
by convention; set by
OS)
Mask
table
for
convert
(Std.
Microcode; set
by
OS)
Saved
interrupt PC
(Std.
Microcode)
Interrupt Transfer Vector
(Std.
Microcode)
Disk
command block address (Std. Microcode)
Disk
status at start
of
current sector (Std. Microcode)
Disk
address of latest
disk
command
(Std.
Microcode)
Sector interrupt bit mask
(Std.
Microcode)
Interval timer time
(Std. Microcode)
Trap saved
PC (Std. Microcode)
Trap vector
(Std.
Microcode)
Timer data
(OS)
Ethernet post location
(Std.
Microcode)
Ethernet mterrupt bit
mask
(Std.
Microcode)
Ethernet
ending count (Std. Microcode).
Ethernet
load.
location
(Std.
Microcode)
Ethernet input buffer
coun~
(Std. Microcode)
Ethernet input buffer poinier
(Std. Microcode)
Ethernet output buffer count
(Std. Microcode)
Ethernet output buffer pointer
(Std. Microcode)
Ethernet host address
(Std.
Microcode)
Reserved
for
Ethernet expansion (Std. Microcode)
Alto
IIII
indication that microcode
can
interrogate (O=Alto I,
-l=Alto
II)
Posted by parity task when a main memory parity error
is
detected.
::
(Std. Microcode)
(Note:
Disk and Ethernet bootstrap loaders run in
622-777.)
700-707
Saved
registers (Swat)
Page
376B:
177016-177017
177020-177023
177024
177025
177026
177030-177033
177034-177037
Page
377B:
177740-177757
UTILOUT
XBUS
MEAR
MESR
MECR
UTIUN
KBDAD
Printer output
(Std. Hardware)
Utility input bus (Alto II
Std.
Hardware) .
Memory Error Address Register (Alto
If
Std.
Hardware)
Memory error status register (Alto II
Std.
Hardware)
Memory error control register (Alto II
Std. Hardware)
Printer status, mouse,
keyset
(all
4 locations return same thing)
Undecoded keyboard
(Std.
Hardware) . .
BANKREGS
Extended memory option bank registers
--
see
section
2.3
68
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