Siemens CPU 948 User Manual

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

Siemens CPU 948 Specifications

General

Brand	Siemens
Model	CPU 948
Category	Controller
Language	English