Omron CVM1D Operation Manual page 107

Data Areas, Definers, and Flags
Flags
Caution
!
Indirect Addressing
BCD Addressing
102
The Flags subsection lists flags that are affected by execution of an instruction.
These flags include the following Auxiliary Area flags.
Abbreviation
ER
CY
GR
EQ
LE
N
ER is the flag most commonly used for monitoring an instruction's execution.
When ER goes ON, it indicates that an error has occurred in attempting to
execute an instruction. The Flags subsection of each instruction lists possible
reasons for ER going ON. ER will turn ON if operands are not entered correctly.
Most instructions are not executed when ER is ON. A table of instructions and
the flags they affect is provided in Appendix B Error and Arithmetic Flag Opera-
tion.
The DM or EM Area can be used to indirectly address an operand. Indirect DM or
EM addressing is specified by placing an asterisk before the D or E: *D or *E.
(The EM Area is contained in the CV1000-DMjj1 EM Unit, sold separately.)
The operation of indirect addressing is affected by the PC Setup specified from
the SSS. The PC Setup can be used to specify whether the content of a word
containing an indirect address contains the BCD data area address or contains
the binary (hexadecimal) PC memory address.
When indirect DM data is designated as BCD, the address of the desired word
must be in BCD and it must specify the data area address of a word within the
DM or EM Area. The content of the operand word containing the indirect address
(e.g., *D00000) has to be in BCD and has to be between 0000 and 9999. Al-
though DM and EM Area addresses go to D24575 and E32765, only the first
10,000 words can be indirectly addressed when indirect DM data is designated
as BCD.
When an indirect DM or EM address is specified in BCD, the DM or EM word
specified for the operand will contain the address of the DM or EM word that con-
tains the data that will be used as the operand of the instruction. If, for example,
*D00001 was designated as the first operand of MOV(030), the contents of
D00001 was 2222, and D02222 contained 5555, the value 5555 would be
moved to the word specified for the second operand.
(030)
MOV *D00001
A001
Indirect
address
Name
Instruction Execution Error Flag
Carry Flag
Greater Than Flag
Equals Flag
Less Than Flag
Negative Flag
Word Content
D00000 4C59
D00001 2222
D00002 F35A
D02222 5555
D02223 2506
D02224 D541
Section 5-3
Bit
A50003
A50004
A50005
A50006
A50007
A50008
Indicates
D02222.
5555 moved
to A001.