Epson S5U1C17001C, Manual

Page: 272 / 742

5-150
EPSOn
S5U1C17001C ManUal
(C COMPilEr PaCkagE fOr S1C17 faMily) (Ver. 1.5.0)
5 gnU17 iDE
Shown below are section locations and file configurations.
VMA
.bssS1
section
.bssS2
section
bss1.o – .bss bss2.o – .bss
library – .bss
boot.o – .text
main.o – .text
library – .text
library – .rodata
boot.o – .rodata
main.o – .rodata
boot.o – .data
main.o – .data
(__
START_data_lma
)
(
__START_rodata
)
(
__START_text
)
0x008000
0x000000
LMA
.data
section
.rodata
section
.text
section
.vector
section
No sections/files
located here
boot.o – .bss
main.o – .bss
boot.o – .data
main.o – .data
(
__START_data
)
0x000000
(
__START_bssS1
)
.data
section
.bss
section
Figure 5.7.6.7 Example of a section location 3
The
.bssS1
and
.bssS2
sections are located in parallel. The application determines which section is man-
aged and what data is used.
Example 4: Executing a program in raM
A routine that requires high-speed processing can be executed in RAM that can be accessed without wait states
to meet specific requirements. In the examples seen so far, only the VMA of the
.text
section is specified,
and the program is executed in ROM. However, the program can be executed in RAM by first specifying the
VMA and LMA, as for the
.data
section, then copying the program to RAM before execution. Additionally,
multiple sections may be allocated to the same area, as in Example 3, and the program may be executed by ex-
changing sections as necessary.
Program storage/
execution area
Constants
and other static data
Program storage area
Unused area
Vector table
Stack area
0x008000
ROM
.textu2
section (LMA)
.textu1
section (LMA)
.data
section (LMA)
.rodata
section (LMA=VMA)
.text
section (LMA=VMA)
.vector
section (LMA=VMA)
Variables
without initial values
Program cache
Variables
with initial values
0x000fbf
0x000000
RAM
.textu1
and
.textu2
sections (VMA)
located in the same area
.data
section (VMA)
.bss
section (VMA)
Program storage area
Variables
with initial values
Program
copied
Figure 5.7.6.8 Allocating a storage area for the program in RAM
Example of a source file configuration
boot.s
(vector table and stack initialization, etc.)
main.c
(main and other functions)
func1.c
(program 1 to be executed in RAM)
func2.c
(program 2 to be executed in RAM)