Technical data

Result After execution of OB 110, the condition code byte will have been
changed in accordance with the function and the contents of ACCU-1.
Possible errors
•• Function number in ACCU-2-L not equal to 1, 2 or 3.
•• One of the bits no. 8 to no. 31 is set in ACCU 1.
If an error occurs,
OB 31 (other runtime errors) is called. If OB 31 is
not loaded, the CPU goes to the STOP mode. In both cases, the error
identifier 1A49H is entered in ACCU-1-L.
Example With OB 110, you can test the operations that evaluate or affect the
condition code register. Its application is, however, not restricted to
the operation test. The following example shows you a further
possible application.
Call distributor
One of four subroutines is to be called depending on the contents of
flag byte FY 0. The four subroutines are assigned to bits F 0.0 to
F 0.3. Only one of these bits can be set at any one time.
:L FY0
:SLW 4 ;shift F 0.0 to F 0.3 four bits to the left
:L KB1 ;load the function number
:TAK
:JU OB110
:JS =M000 ;jump if OS = 1
:JO =M001 ;jump if OV = 1
:JM =M002 ;jump if CC 0 = 1
:JP =M003 ;jump if CC 1 = 1
:
: ;if no bit is set
:
:BEU
:
M000 : ;if F 0.0 = 1
:
:BEU
M001 : ;if F 0.1 = 1
:
:
M002 : ;if F 0.2 = 1
:
:BEU
M003 : ;if F 0.3 = 1
:
:BEU
OB 110: Accessing the Condition Code Byte
CPU 928B Programming Guide
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