# Rules for Operators

To use operators with the `Ivec` classes you must use one of the following three syntax conventions:

`[ Ivec_Class ] R = [ Ivec_Class ] A [ operator ][ Ivec_Class ] B`

Example 1:`I64vec1 R = I64vec1 A & I64vec1 B;`

`[ Ivec_Class ] R =[ operator ] ([ Ivec_Class ] A,[ Ivec_Class ] B)`

Example 2:`I64vec1 R = andnot(I64vec1 A, I64vec1 B);`

`[ Ivec_Class ] R [ operator ]= [ Ivec_Class ] A`

Example 3:`I64vec1 R &= I64vec1 A;`

[ `operator` ] represents an operator (for example, &, |, or ^ )

[ `Ivec_Class` ] represents an `Ivec` class

`R`, `A`, `B` variables are declared using the pertinent `Ivec` classes

The table that follows shows automatic and explicit sign and size typecasting. "Explicit" means that it is illegal to mix different types without an explicit typecasting. "Automatic" means that you can mix types freely and the compiler will do the typecasting for you.

Summary of Rules Major Operators

Operators | Sign Typecasting | Size Typecasting | Other Typecasting Requirements
--- | --- | --- | ---
Assignment | N/A | N/A | N/A
Logical | Automatic | Automatic (to left) | Explicit typecasting is required for different types used in non-logical expressions on the right side of the assignment.
Addition and Subtraction | Automatic | Explicit | N/A
Multiplication | Automatic | Explicit | N/A
Shift | Automatic | Explicit | Casting Required to ensure arithmetic shift.
Compare | Automatic | Explicit | Explicit casting is required for signed classes for the less-than or greater-than operations.
Conditional Select | Automatic | Explicit | Explicit casting is required for signed classes for less-than or greater-than operations.

## Data Declaration and Initialization

The following table shows literal examples of constructor declarations and data type initialization for all class sizes. All values are initialized with the most significant element on the left and the least significant to the right.

Declaration and Initialization Data Types for Ivec Classes

Operation | Class | Syntax
--- | --- | ---
Declaration | M128 | `I128vec1 A; Iu8vec16 A;`
Declaration | M64 | `I64vec1 A; Iu8vec8 A;`
__m128 Initialization | M128 | `I128vec1 A(__m128 m); Iu16vec8(__m128 m);`
__m64 Initialization | M64 | `I64vec1 A(__m64 m);Iu8vec8 A(__m64 m);`
__int64 Initialization | M64 | `I64vec1 A = __int64 m; Iu8vec8 A =__int64 m;`
int i Initialization | M64 | `I64vec1 A = int i; Iu8vec8 A = int i;`
int Initialization | I32vec2 | `I32vec2 A(int A1, int A0);` `Is32vec2 A(signed int A1, signed int A0);` `Iu32vec2 A(unsigned int A1, unsigned int A0);`
int Initialization | I32vec4 | `I32vec4 A(int A3, int A2, int A1, int A0);` `Is32vec4 A(signed int A3, ..., signed int A0);` `Iu32vec4 A(unsigned int A3, ..., unsigned int A0);`
short int Initialization | I16vec4 | `I16vec4 A(short A3, short A2, short A1, short A0);` `Is16vec4 A(signed short A3, ..., signed short A0);` `Iu16vec4 A(unsigned short A3, ..., unsigned short A0);`
short int Initialization | I16vec8 | `I16vec8 A(short A7, short A6, ..., short A1, short A0);` `Is16vec8 A(signed A7, ..., signed short A0);` `Iu16vec8 A(unsigned short A7, ..., unsigned short A0);`
char Initialization | I8vec8 | `I8vec8 A(char A7, char A6, ..., char A1, char A0);` `Is8vec8 A(signed char A7, ..., signed char A0);` `Iu8vec8 A(unsigned char A7, ..., unsigned char A0);`
char Initialization | I8vec16 | `I8vec16 A(char A15, ..., char A0);` `Is8vec16 A(signed char A15, ..., signed char A0);` `Iu8vec16 A(unsigned char A15, ..., unsigned char A0);`

Parent topic: Integer Vector Classes