VHDL Operators

** exponentiation, numeric ** integer, result numeric
abs absolute value, abs numeric, result numeric
not complement, not logic or boolean, result same

* multiplication, numeric * numeric, result numeric
/ division, numeric / numeric, result numeric
mod modulo, integer mod integer, result integer
rem remainder, integer rem integer, result integer

+ unary plus, + numeric, result numeric
- unary minus, - numeric, result numeric

+ addition, numeric + numeric, result numeric
- subtraction, numeric - numeric, result numeric
& concatenation, array or element & array or element,
result array

sll shift left logical, logical array sll integer, result same
srl shift right logical, logical array srl integer, result same
sla shift left arithmetic, logical array sla integer, result same
sra shift right arithmetic, logical array sra integer, result same
rol rotate left, logical array rol integer, result same
ror rotate right, logical array ror integer, result same

= test for equality, result is boolean
/= test for inequality, result is boolean
< test for less than, result is boolean
<= test for less than or equal, result is boolean
> test for greater than, result is boolean
>= test for greater than or equal, result is boolean

and logical and, logical array or boolean, result is same
or logical or, logical array or boolean, result is same
nand logical complement of and, logical array or boolean, result is same
nor logical complement of or, logical array or boolean, result is same
xor logical exclusive or, logical array or boolean, result is same
xnor logical complement of exclusive or, logical array or boolean, result is same

Source