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CubeSuite+ Ver.1.00.00
APPENDIX B COMMAND REFERENCE
(c) To call function in the flash area from the boot area
When a function in the flash area is called from the boot area, the address of the function cannot be known
from the boot area because the function size, etc., have been changed in the flash area. In other words, a
function in the flash area cannot be directly called. To solve this, execution jumps to the branch table in the
flash area.
Execute the jump instruction from that table to the relevant function and jump to the intended function.
Figure B-17. From Boot Area to Flash Area
In boot area
In flash area
void
void
func_rom1(void)
func_flash1(void)
{
{
:
:
}
}
void
void
func_rom2(void)
func_flash2(void)
{
{
:
:
func_flash();
func_flash1();
:
:
}
}
Execution jumps to the branch table of
flash area.
Branch table
jr _func_flash1
jr _func_flash2
In the same manner as functions, this is relevant to referencing external variables.
A global variable defined in the flash area cannot be referenced from the boot area. Therefore, an external
variable of the same name can be defined in both the boot area and flash area. Each of these external
variables is referenced only from the respective areas.
(d) To call function in the boot area from the flash area
When a function in the boot area is called from the flash area, the contents of the boot area are not changed.
Therefore, a function in the boot area can be directly called from the flash area.
R20UT0557EJ0100 Rev.1.00
Apr 01, 2011
Page 558 of 782
