Linkage Kit Manual V6-00 - Fujitsu

CHAPTER 5 SPECIFICATIONS OF A LINKER
5.9 Sections to be Transferred from ROM to RAM
When developing a program using a C/C++ compiler, a variable with an initial value is
created and you must often rewrite the variable and perform other processing.
Such a variable, being rewritten at the time of execution, must be in RAM when the
application is executed. Therefore, in a program to be imported, the initial value data
must be placed in ROM and transferred to RAM before the application is executed.
The section to be transferred from ROM to RAM is a function that enables such a usage.
■ Sections to be Transferred from ROM to RAM
When developing a program using a C/C++ compiler, a variable with an initial value is created and you
must often rewrite the variable and perform other processing.
In a program to be imported, the variable data with initial values are placed in ROM. However, since it is
being rewritten at the time of execution, it must be in RAM when the application is executed.
Therefore, the initial value data is transferred to RAM before the application is executed.
To facilitate such a usage, this linker, as long as the sections to be transferred from ROM to RAM are
specified, supports the system of solving the reference addresses of a program on RAM and placing the
data with initial values on ROM.
■ Using the Sections to be Transferred from ROM to RAM
Specify the sections to be transferred from ROM to RAM in the -sc option as follows:
The sections containing variables with initial values shall be INIT.
DATA shall be the sections containing variables without initial values, start shall be a program used to
transfer the data of variables with initial values on ROM to RAM, and CODE shall be the application
program to be executed.
-sc DATA+INIT=0x1000,start+CODE+@INIT=0xC000
As shown in the figure, specify to locate INIT on RAM (0x1000), and also to locate INIT on ROM
(0xC000) using a section name starting with an at sign, @.
If the section is thus located, INIT is processed as a section to be transferred from ROM to RAM, and the
location is as shown in Figure 5.9-1. Then, the addresses are solved on RAM and the initial value data is
located on ROM.
82 PART II LINKER