CC78K0S Datasheet, PDF (414/520 Pages) NEC – C Compiler Ver.1.30 or Later Language

CHAPTER 11 EXTENDED FUNCTIONS
Register Direct Reference Function
#pragma realregister
RESTRICTIONS
• The function name of a register direct reference cannot be not used as a function name. The register direct
reference function is described in lowercase letters. A function described in uppercase letters are regarded as
an ordinary function.
• The values of the A and AX registers and CY flag that are set by the _ _ seta, _ _setax, and _ _setcy
functions are not retained in the next code generation.
• The timing that is referenced by the A and AX registers and CY flag with the _ _ geta, _ _getax, and _
_getcy functions, corresponds to the evaluation sequence of the expression.
COMPATIBILITY
<From another C compiler to this C compiler>
• If the register direct reference function is not used, modification is not necessary.
• To change to the register direct referencing function, modify according to USAGE above.
<From this C compiler to another C compiler>
• Register direct reference function names can be used as function names by deleting the #pragma
realregister directive or delimiting #ifdef.
• To use pragma realregister as a register direct reference function, modify the program according to the
specifications of each C compiler (#asm, #endasm, or asm();, etc.).
CAUTION
• There is no guarantee that CY, A, AX will be saved as intended before the register direct reference function is
executed. Accordingly, it is recommended to use this function before values change by describing it in the first
term of the expression.
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User’s Manual U14872EJ1V0UM