VHDL MOD和REM（轉）

mod(取模)and rem(取餘)

VHDL has mod and rem. They return the same value if both arguments are positive.

but, they produce different results for negative inputs:

5 mod 3 = 2

(-5) mod 3 = 1

5 mod (-3) = -1

(-5) mod (-3) = -2

for mod， the result has the same sign with the first argument.

whereas

5 rem 3 = 2

(-5) rem 3 = -2

5 rem (-3) = 2

(-5) rem (-3) = -2

for rem，the result has the same sign with the second argument.

A rem B = A - ( A / B ) * B --餘數運算符 利用操做數A決定結果的正負號

 

取餘運算（a REM b）的符號與a相同，其絕對值小於b的絕對值。

 

A mod B = A - B * N --取模運算符 利用操做數B決定結果的正負號

 

取模運算（a MOD b）的符號與b相同，其絕對值小於b的絕對值。