Siemens CPU 948 Programming Manual page 386

Memory Access via Address in ACCU 1
Example 2 continued:
Flag assignment:
FW 10: Bits 4 to 19 of the start address of the DB/DX (points to DW 0)
FW 12: Length of the DB/DX (number of data words)
FD 14: Address of the last data word in the DB/DX + 1 (physical address)
FB 6
SEGMENT 1
NAME :FILL DB
0005 :
0006 :L DH
0009 :L KF
000B :+D
000C :
000D :LIR
000E :T FW
000F :L KB
0010 :!=F
0011 :JC =NIVO
0012 :
0013 :L FW
0014 :SLD
0015 :L KB
0016 :-D
0017 :LIR
0018 :ADD BN
0019 :
001A :T FW
001B :
001C :L FW
001D :L FW
001E :SLD
001F :+D
0020 :T FD
0021 :
0022 :L KH
0024 :
0025 :L FD
0026 :ENT
0027 :
0028 :L FW
0029 :SLD
002A :
002B SCHL :
002C :
002D :
002E :
002F :TIR
0030 :
0031 :
0032 :ADD DH
0035 :
0036 :><D
0037 :JC =SCHL
0038 :
0039 WEIT :
003A :
003B :
003C :BEU
003D :
003E NIVO :
003F :BE
9 - 16
0000 Writing a DB with a constant
! Required flags: FY 10 to FY 17
000E EC00 Start addr. of the DB list
+100 plus the DB number
= Address list entry of DB 100
(Bits 4 to 19)
1 Start addr. DB 100 to ACCU 1
10 Buffer start addr.
0 (Paragraph address)
If start addr. = 0, then
DB does not exist
10 Start addr. of DB (1st DW)
4 Convert addr. to physical address
1 Find out DB length via
5th word in block header
1 Length including block header to ACCU 1
-5 Number of DWs = total length - 5 words (header)
12 Buffer length
12 Number of data words +
10 start address (DW 0 converted to
4 physical address)
produces
14 address of the last DW + 1
A5A5 Constant, written to all data words
14 Address of the last DW + 1
Shift constant to ACCU-3-L
(= register 10)
10 Convert address of 1st data word (DW 0)
4 to physical address
Loop:
ACCU 1: address of DW to be written to
ACCU 2: address of last DW + 1
ACCU 3: constant
10 Store the value of ACCU-3-L in the DW with
the address in ACCU 1
0000 0001 Increment address by 1
Scan whether last DW reached
(if not, return to the loop)
Continue the program ...
after all DWs have been written to ...
If DB 100 does not exist
!
CPU 948 Programming Guide
C79000-G8576-C848-04