Omron CJ2 - 02-2010 User Manual page 343

10 CPU Unit Functions
Differences between Instructions Executed Normally and Instructions
Executed in the Background
The differences between normal instruction execution and execution in the background are listed
below.
Outputting to Index Registers (IR)
If MAX(182), MAXL(174), MAXF(176), MAXD(178), MIN(183), MINL(175), MINF(177), or
MIND(179) is executed to output the I/O memory map address of the word containing the minimum
10
or maximum value to an index register, the address will not be output to the index register and will be
output to A595 and A596 instead.
To store the address in an index register in the same way as for normal execution, use a Data Move
instruction (e.g., MOVL(498)) to copy the address in A595 and A596 to an index register.
Conditions Flags
Conditions Flags will not be updated following execution of instructions processed in the back-
ground. To access the Conditions Flag status, execute an instruction that affects the Conditions
Flags in the same way, as shown in the following example, and then access the Conditions Flags.
Outputting to Index Register IR00
If SRCH(181) is executed to output the I/O memory map address of the word containing the match-
ing value (the first word if there is more than one) to an index register, the address will not be output
to the index register and will be output to A595 and A596 instead.
Outputting to Data Registers for SRCH(181)
If SRCH(181) is executed to output the matching data to a data register, the data will not be output to
the data register and will be output to A597 instead.
Matching Text Strings
If SRCH(181) finds matching data, it will not turn ON the Equals Flag, but will turn ON A598.01
instead.
Instruction Errors
If an instruction execution error or illegal access error occurs for an instruction being processed in
the background, the ER or AER Flags will not be turned ON and A395.10 will be turned ON instead.
A395.10 will remain ON until the next time an instruction is processed in the background.
Outputting to Data Registers for MAX(182) or MIN(183)
If MAX(182), MAXL(174), MAXF(176), MAXD(178), MIN(183), MINL(175), MINF(177), or
MIND(179) is executed with a data register (DR0 to DR15) specified as the output word for the mini-
mum or maximum value, an instruction execution error will occur and the ER Flag will turn ON.
CJ2 CPU Unit Software User's Manual 10-13