有關 AVR 單片機乘法等數學運算等問題

lucky_jeck

請問各位,在 IAR AVR 中是否支持一般 C 語言中的 + - * / 等數學運算 ?
如果支持,那 IAR AVR 的庫函數中為什麼還有很多的數學運算函數??,像以下的這些?
望各位賜教.


INTRINSICS.H


#ifdef __HAS_MUL__
__intrinsic unsigned int  __multiply_unsigned(unsigned char, unsigned char);
__intrinsic signed int    __multiply_signed(signed char, signed char);
__intrinsic signed int    __multiply_signed_with_unsigned(signed char, unsigned char);

__intrinsic unsigned int  __fractional_multiply_unsigned(unsigned char, unsigned char);
__intrinsic signed int    __fractional_multiply_signed(signed char, signed char);
__intrinsic signed int    __fractional_multiply_signed_with_unsigned(signed char, signed char);
#endif