pcp_reference_guide_v2.5 - Tasking

8−46PCP Reference ManualThe properties of the load−time and run−time start address are:• At run−time, before using an element in an overlay group, theapplication copies the sections from their load location to theirrun−time location, but only if these two addresses are different. Fornon−overlay sections this happens at program start−up.• The start addresses cannot be set to absolute values for unrestrictedgroups.• For non−overlay groups that do not have an overlay parent, theload−time start address equals the run−time start address.• For any group, if the run−time start address is not set, the linkerselects an appropriate address.LINKER SCRIPT LANGUAGEFor overlays, the linker reserves memory at the run−time start address aslarge as the largest element in the overlay group.• The page keyword tells the linker to place the group in one page.Instead of specifying a run−time address, you can specify a page andoptional a page number. Page numbers start from zero. If you omit thepage number, the linker chooses a page.The page keyword refers to pages in the address space as defined inthe architecture definition.• With the page_size keyword you can override the page alignmentand size set on the address space. See also the page_size keyword insection 8.5.3, Defining Address Spaces.group (page, ... )group (page = 3, ...)8.8.3 CREATING OR MODIFYING SPECIAL SECTIONSInstead of selecting sections, you can also create a reserved section or anoutput section or modify special sections like a stack or a heap. Becauseyou cannot define these sections in the input files, you must use the linkerto create them.Stack• The keyword stack tells the linker to reserve memory for the stack.The name for the stack section refers to the stack as defined in thearchitecture definition. If no name was specified in the architecturedefinition, the default name is stack.