共用方式為


_mm_cmpestrs

Microsoft Specific

Emits the Streaming SIMD Extensions 4 (SSE4) instruction pcmpestri. This instruction compares to parameters.

int _mm_cmpestrs (
   __m128i a, 
   int la,
   __m128i b,
   int lb, 
   const int mode
); 

Parameters

Parameter

Description

[in] a

A string fragment with a maximum size of 16 byte characters or 8 word characters.

[in] la

An integer that specifies the size of the string in a.

[in] b

A string fragment with a maximum size of 16 byte characters or 8 word characters.

[in] lb

An integer that specifies the size of the string in b.

[in] mode

A constant that indicates whether characters are bytes or words, the type of comparison to do, and the format of the returned value.

Return value

One if the absolute value of la is less than MaxSize. Otherwise, zero. When one is returned, it means that a contains the ending fragment of the string that is being compared.

Requirements

Intrinsic

Architecture

_mm_cmpestrs

x86, x64

Header file <nmmintrin.h>

Remarks

b0, b1, b2… indicate the first, second, third… characters in b. b0 is stored in the least significant bits of b. The same notation applies to a. MaxSize is either 16 for byte characters or 8 for word characters. This is the maximum number of characters that fit into a __m128i data type. The lower 7 bits in mode determine the type of the input characters, which comparison to run, and the format of the return value. They are described in the following table:

mode in binary

Defined constant

Description

xxxxxx00

SIDD_UBYTE_OPS

a and b contain strings of unsigned 8-bit characters.

xxxxxx01

SIDD_UWORD_OPS

a and b contain strings of unsigned 16-bit characters.

xxxxxx10

SIDD_SBYTE_OPS

a and b contain strings of signed 8-bit characters.

xxxxxx11

SIDD_SWORD_OPS

a and b contain strings of signed 16-bit characters.

xxxx00xx

SIDD_CMP_EQUAL_ANY

Find if equal any mode:

For each character c in a, determine whether any character in b is equal to c.

xxxx01xx

SIDD_CMP_RANGES

Find in ranges mode:

For each character c in a, determine whether b0 <= c <= b1or b2 <= c <= b3…

xxxx10xx

SIDD_CMP_EQUAL_EACH

Find if equal each mode:

This implements the string equality algorithm.

xxxx11xx

SIDD_CMP_EQUAL_ORDERED

Find if equal ordered mode:

This implements the substring search algorithm.

xx01xxxx

SIDD_NEGATIVE_POLARITY

Negation of resulting bitmask.

xx11xxxx

SIDD_MASKED_NEGATIVE_POLARITY

Negation of resulting bitmask except for bits that have an index larger than the size of a or b (see details of pcmpestri instruction).

Before using this intrinsic, software must ensure that the processor supports the instruction.

Example

See the example for _mm_cmpestra.

See Also

Concepts

_mm_cmpestra

_mm_cmpestrc

_mm_cmpestri

_mm_cmpestrm

_mm_cmpestro

_mm_cmpestrz

_mm_cmpistra

_mm_cmpistrc

_mm_cmpistri

_mm_cmpistrm

_mm_cmpistro

_mm_cmpistrs

_mm_cmpistrz

__m64