Technical data

Possible errors

•• No data block opened

•• Opened data block does not exist or is not long enough to take the

required number of BSTACK entries

•• Illegal parameters in ACCU 1 and ACCU 2

If an error occurs, the RLO and the condition codes CC 0 and CC 1

are set (RLO, CC 0 and CC 1 = 1). The remaining bit and word

condition codes are cleared. The contents of ACCU-1-L are set to "0".

Example

You want to read the last three BSTACK entries into data block DX 10.

You want the entries to be stored in DX 10 from data word DW 16 onwards

(see Figs. 6.4 and 6.5).

:CX DX 10 ;open DX 10

:L KY 0,16 ;BSTACK entries to be stored from DW 16 onwards

:L KY 0,3 ;you require the last three BSTACK entries

JU OB 170

Six blocks are entered in the BSTACK as follows:

Continued on the next pag

Element 56

Element 57

Element 58

Element 59

Element 60

Element 61

Element 62

Element 1

BSTACK

Depth 1 (last BSTACK entry)

Depth 2

Depth 3

(first BSTACK entry)

Fig. 6-4 Contents of the BSTACK in this example

OB 170: Read Block Stack (BSTACK)

CPU 928B Programming Guide

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