Chapter 2. Program Organization
16 PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual GFK-2950C
External Blocks and Local Data
External blocks support the use of %P global data. External blocks do not have their own %L data,
but instead inherit the %L data of their calling blocks. They also inherit the FST_EXE system
reference and the time-stamp data that is used to update timer function blocks from their calling
blocks. If %L references are used within an external block and the block is called by _MAIN, %L
references will be inherited from the %P references wherever encountered in the external block (for
example, %L0005 = %P0005).
Initialization of C Variables
When an external block is stored to the CPU, a copy of the initial values for its global and static
variables is saved. However, if static variables are declared without an initial value, the initial value is
undefined and must be initialized by the C application. (Refer to Global Variable Initialization and
Static Variable in the C Programmer’s Toolkit for PACSystems, GFK-2259). The saved initial values are
used to re-initialize the block’s global and static variables whenever the CPU transitions from STOP
Mode to RUN Mode.
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