_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.