Developer Guide and Reference

Contents

Shift Operators

The right shift argument can be any integer or Ivec value, and is implicitly converted to a M64 data type. The first or left operand of a
<<
can be of any type except
I[s|u]8vec[8|16]
.
Example Syntax Usage for Shift Operators
Automatic size and sign conversion.
Is16vec4 A,C;
Iu32vec2 B;
C = A;
A&B returns
I16vec4
, which must be cast to
Iu16vec4
to ensure logical shift, not arithmetic shift.
Is16vec4 A, C;
Iu16vec4 B, R;
R = (Iu16vec4)(A & B) C;
A&B returns
I16vec4
, which must be cast to
Is16vec4
to ensure arithmetic shift, not logical shift.
R = (Is16vec4)(A & B) C;
Shift Operators with Corresponding Intrinsics
Operation
Symbols
Syntax Usage
Intrinsic
Shift Left
<<
&=
R = A << B
R &= A
_mm_sll_si64
_mm_slli_si64
_mm_sll_pi32
_mm_slli_pi32
_mm_sll_pi16
_mm_slli_pi16
Shift Right
>>
R = A >> B
R >>= A
_mm_srl_si64
_mm_srli_si64
_mm_srl_pi32
_mm_srli_pi32
_mm_srl_pi16
_mm_srli_pi16
_mm_sra_pi32
_mm_srai_pi32
_mm_sra_pi16
_mm_srai_pi16
Right shift operations with signed data types use arithmetic shifts. All unsigned and intermediate classes correspond to logical shifts. The following table shows how the return type is determined by the first argument type.
Shift Operator Overloading
Option
R
Right Shift
Left Shift
A
B
Logical
I64vec1
>>
>>=
<<
<<=
I64vec1 A;
I64vec1 B;
Logical
I32vec2
>>
>>=
<<
<<=
I32vec2 A
I32vec2 B;
Arithmetic
Is32vec2
>>
>>=
<<
<<=
Is32vec2 A
I[s|u][N]vec[N] B;
Logical
Iu32vec2
>>
>>=
<<
<<=
Iu32vec2 A
I[s|u][N]vec[N] B;
Logical
I16vec4
>>
>>=
<<
<<=
I16vec4 A
I16vec4 B
Arithmetic
Is16vec4
>>
>>=
<<
<<=
Is16vec4 A
I[s|u][N]vec[N] B;
Logical
Iu16vec4
>>
>>=
<<
<<=
Iu16vec4 A
I[s|u][N]vec[N] B;

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.