Texas Instruments C28 Series, Student Manual

Page: 28 / 342

Creating a Linker Command File
Following is a list of the sections that are created by the compiler. Along with their description,
we provide the Section Name defined by the compiler.
Compiler Section Names
Compiler Section Names
Name Name Description Description Link Location Link Location
.text
.text
code
code
program
program
. . cinit cinit initialized global and static variables program initialized global and static variables program
.
.
econst
econst
constant data (e.g. const
constant data (e.g. const
int
int
k = 3;) data
k = 3;) data
.switch .switch tables for switch statements tables for switch statements prog prog /low 64K data /low 64K data
.
.
pinit
pinit
tables for global constructors (C++)
tables for global constructors (C++)
program
program
Name Name Description Description Link Location Link Location
.
.
ebss
ebss
global & static variables
global & static variables
data
data
.stack stack space
.stack stack space
low 64K data
low 64K data
. . esysmem esysmem memory for far memory for far malloc malloc functions functions data data
Initialized Sections Initialized Sections
Uninitialized
Uninitialized
Sections
Sections
Sections of a C program must be located in different memories in your target system . This is the
big advantage of creating the separate sections for code, constants, and variables. In this way,
they can all be linked (located) into their proper memory locations in your target embedded
system. Generally, they’re located as follows:
Program Code (.text)
Program code consists of the sequence of instructions used to manipulate data, initialize system
settings, etc. Program code must be defined upon system reset (power turn-on). Due to this basic
system constraint it is usually necessary to place program code into non-volatile memory, such as
FLASH or EPROM.
Constants (.cinit – initialized data)
Initialized data are those data memory locations defined at reset.It contains constants or initial
values for variables. Similar to program code, constant data is expected to be valid upon reset of
the system. It is often found in FLASH or EPROM (non-volatile memory).
Variables (.ebss – uninitialized data)
Uninitialized data memory locations can be changed and manipulated by the program code during
runtime execution. Unlike program code or constants, uninitialized data or variables must reside
in volatile memory, such as RAM. These memories can be modified and updated, supporting the
way variables are used in math formulas, high-level languages, etc. Each variable must be
declared with a directive to reserve memory to contain its value. By their nature, no value is
assigned, instead they are loaded at runtime by the program
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