Zilog Z8F0130 - Manual (Page 271)

UM013037-1212 Linker Command Files for C Programs
Zilog Developer Studio II – Z8 Encore!
User Manual
247
Linker Command Files for C Programs
This section describes how the Z8 Encore! linker is used to link a C program. To learn
more about the linker and the various commands it supports, see the
Using the Linker/
Locator section on page 345. A C program consists of compiled and assembled object
module files, compiler libraries, user-created libraries, and special object module files
used for C run-time initializations. These files are linked based on the commands given in
the linker command file. Because the linker command file coordinates the actions of the
compiler and linker, it is appropriate to discuss this topic in this section.
The default linker command file is automatically generated by the ZDS II IDE whenever a
build command is issued. It has information about the ranges of various address spaces
for the selected device, the assignment of segments to spaces, order of linking, and so on.
The default linker command file can be overridden by the user.
The linker processes the object modules (in the order in which they are specified in the
linker command file), resolves the external references between the modules, and then
locates the segments into the appropriate address spaces as per the linker command file.
The linker depicts the memory of the Z8 Encore! CPU using a hierarchical memory model
containing spaces and segments. Each memory region of the CPU is associated with a
space. Multiple segments can belong to a given space. Each space has a range associated
with it that identifies valid addresses for that space. The hierarchical memory model for
the Z8 Encore! CPU is shown in Figure 139. Figure 140 depicts how the linker links and
locates segments in different object modules.
Table 49. Segments
Segment Description
NEAR_DATA near initialized global and static data
NEAR_BSS near uninitialized global and static data
NEAR_TEXT near constant strings
FAR_DATA far initialized global and static data
FAR_BSS far uninitialized global and static data
FAR_TEXT far constant strings
ROM_DATA ROM global and static data
ROM_TEXT ROM constant strings
PRAMSEG Program ram code
fname_TEXT ROM code for file fname (fname is translated in some cases)
__VECTORS_nnn ROM interrupt vector at address nnn
STARTUP ROM C startup