CC78K4 Datasheet, PDF (430/523 Pages) NEC – CC78K4 Ver.2.30 or Later, C Compiler Language

CHAPTER 11 EXTENDED FUNCTIONS
(35) Function call function from the boot area to the flash area
Function Call Function from the Boot Area to the Flash Area #pragma ext_func
Caution Do not use this flash function for devices that have no flash area self-rewrite function.
Operation is not guaranteed if it is used.
This function enables the flash memory rewrite function of devices.
FUNCTIONS
• Function calls from the boot area to the flash area are executed via the flash area branch table.
• Functions in the boot area can be called directly from the flash area.
EFFECT
• It becomes possible to call a function in the flash area from the boot area.
USAGE
• The following #pragma directive specifies the function name and ID value in the flash area called from the
boot area.
#pragma ∆ ext_func ∆ function-name ∆ ID value
This #pragma directive is described at the beginning of the C source. The following items can be described before
this #pragma directive.
• Comments
• Directives that do not generate the definition/reference of variables or functions among the preprocessing
directives.
RESTRICTIONS
• The ID value is set to 0 to 255 (0xFF).
• If #pragma ext_table does not exist before #pragma ext_func, it results in an error.
• If the same function has a different ID value or a different function has the same ID value, an error occurs. (a)
and (b) below are errors.
(a) #pragma ext_func f1 3
#pragma ext_func f1 4
(b) #pragma ext_func f1 3
#pragma ext_func f2 3
• If a function is called from the boot area to the flash area and there is no corresponding function definition in
the flash area, the linker cannot conduct a check. This is the user’s responsibility.
• The callt and callf functions can only be located in the boot area. If the callt and callf functions are defined in
the flash area (when the -ZF option is specified), it results in an error.
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User’s Manual U15556EJ1V0UM