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Overlay Groups

When performing overlay analysis, the linker creates groups of segments that are overlaid. The group name indicates the memory type of the variables that it includes.

Group Name Segment
Prefix
Memory
Model
Description
_BIT_GROUP_ ?BI? All Variables and arguments of type bit.
_DATA_GROUP_ ?DT? SMALL Variables and arguments other than bit.
_PDATA_GROUP_ ?PD? COMPACT Variables and arguments other than bit.
_XDATA_GROUP_ ?XD? LARGE Variables and arguments other than bit.

When the linker overlays function data memory and creates a group, that groups appears in the linker map file's memory map section.

START     STOP      LENGTH    ALIGN  RELOC    MEMORY CLASS   SEGMENT NAME
=========================================================================

* * * * * * * * * * *   D A T A   M E M O R Y   * * * * * * * * * * * * *
000000H   000007H   000008H   ---    AT..     DATA           "REG BANK 0"
000008H   00001AH   000013H   BYTE   UNIT     DATA           _DATA_GROUP_
00001BH   00001BH   000001H   BYTE   UNIT     IDATA          ?STACK

Groups are created based on the memory model of the function (which specifies the memory class where parameters and variables are stored) and on any variables defined with a specific memory space.

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