Technical data

Result After OB 170 has been called successfully
•• the offset in the data block is still contained in ACCU-2-L
•• the actual number of BSTACK elements represented is in
ACCU-1-L
1)
•• The RLO is cleared.
•• The condition codes CC 0 and CC 1 can be analyzed.
•• All other bit and word condition codes are cleared.
1)
Possible values: 0 - 62, where the represented number is less than or equal to
the required number
0 = "no BSTACK entry exists" or "error"
(Multiply the contents of ACCU-1-L by four to obtain the
number of data words written to the DB).
RLO, CC 0 and CC 1
settings
RLO CC 1 CC 0 Scan with Meaning
0
0
0
1
0
0
1
1
1
0
0
1
JM
JZ
JP
JC
Existing number of
BSTACK elements
< required number
Existing number of
BSTACK elements
= required number
Existing number of
BSTACK elements
> required number
Error
Storing the BSTACK
elements in open data blocks
The contents of the BSTACK are stored in the data block as follows
when OB 170 is called (see also Fig. 6-3):
A = BSTACK element number (62 to 1)
(As soon as the last BSTACK element is output you can determine the
remaining space: A = 17 reserve = A - 1 = 16)
B = Depth if the BSTACK element (1 to 62)
OB 170: Read Block Stack (BSTACK)
CPU 928B Programming Guide
6 - 54 C79000-B8576-C898-01