HP 9845B/C CE Handbook page 98

9-2
9845B/C
Mainframe Diagrams
Memory Map
98458/C Memory Architecture
Each address is a 16 bit word (2 bytes).
Blocks have 32k addresses, or 64k bytes.
Some blocks don't use all32k addresses.
Even blocks (and 1) are RWM.
Odd blocks (except 1) are ROM.
Here's how this memory map is laid out;
Down the left column:
Block numbers (octal) and the assembly the memory is in.
If the memory is standard, an S; if optional, an O.
Across the top:
Addresses (octal) is lOk/20k ranges across the top.
Data in the map:
The information in that block/address range of memory. If ROM, it's processor, use
and option ROM product number. (N) Numbers in parentheses refer to notes at the
end of the map. Empty areas either don't exist or are not presently used.
A complete list of system and option ROMs, with revisions and part numbers is available by
listing on the printer, the 9845B/C System Exerciser Tape #2, the ROMREV file starting with
line 5190.
Notes (shown in parentheses in memory map)
1. Addresses 0-37 in each block are common processor addresses. RWM and ROM use
addresses 000040-177777.
2. This location is ROM for CRT graphics. See parts list for details.
3. More CRT ROM, the parts list shows specifics.
4. These are the keyboard language ROMs, six sets exist for six languages. Refer to parts list
for specifics.
5. Two optional graphics ROMs are available,
98411A, for the standard CRT, addresses 030000-047777.
98411B, for enhanced and/or color CRT, addresses 030000-067777.
Special Note on Block 0 RWM Allocations:
Block 0 contains the following map at execution time,
If no A26 optional RWM assemblies are installed,
Address 177777 Block DeSCriptor
System RWM
LPU System RWM
Option ROM RWM
Binary Programs Area
Execution Stack
Buffer Space
Program Segments
Value Area
COM System Common
lCOM Assembly Common