The DBA register changes if one of the following occurs:
•• Another data block is opened,
or
•• the program returns to a higher order block after a new data block
is opened in the called block (refer to Section 2.4.3).
Example
Effect of the "CX DX 17" operation on the DBA register:
When DX 17 is called, the address of the memory word in which DW 0 is
stored is entered in the DBA register. In this example, the DBA is
4152H.
Note: In the ISTACK, the address entered in the DBA register appears under
the heading ’DB-ADD’.
5 words
Block header
KH = 0000
KH = 0001
4 151BH
4 151CH
4 151DH
4 151EH
4 151FH
4 1520H
4 1521H
4 1522H
DW 0 (at Paragraph address)
DW 1
DW 2
DBA
Addresses
DX17
.
.
.
Fig. 9-5 Using the DBA register
Memory Access via Address in ACCU 1
CPU 948 Programming Guide
9 - 12 C79000-G8576-C848-04
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