Labels and Jumps

Introduction

Labels serve as destinations for Jumps.

Label Properties:

Label properties:

Labels must always be the first element in a line.
The name must be clear throughout the directory, and it is not upper/lower case sensitive.
Labels can be 256 characters long (max.).
Labels must conform to the IEC name conventions.
Labels are separated by a colon : from the following instruction.
Labels are only permitted at the beginning of "Expressions", otherwise an undefined value can be found in the battery.

Example:
```
start: LD A
       AND B
       OR C
       ST D
       JMP start
```

Jump Properties:

Jump properties:

With JMP operation a jump to the label can be restricted or unrestricted.
JMP can be used with the modifiers C and CN (only if the battery content is data type BOOL).
Jumps can be made within program and DFB sections.
Jumps are only possible in the current section.

Possible destinations are:

the first LD instruction of an EFB/DFB call with assignment of input parameters (see start2),
a normal LD instruction (see start1),
a CAL instruction, which does not work with assignment of input parameters (see start3),
a JMP instruction (see start4),
the end of an instruction list (see start5).

Example

start2: LD A
        ST counter.CU
        LD B
        ST counter.R
        LD C
        ST counter.PV
        CAL counter
        JMPCN start4
start1: LD A
        AND B
        OR C
        ST D
        JMPC start3
        LD A
        ADD E
        JMP start5
start3: CAL counter (
        CU:=A
        R:=B
        PV:=C )
        JMP start1
        LD A
        OR B
        OR C
        ST D
start4: JMPC start1
        LD C
        OR B
start5: ST A