_mm_cmpestra
Microsoft Specific
Emits the Streaming SIMD Extensions 4 (SSE4) instruction pcmpestri This instruction compares two parameters.
int _mm_cmpestra (
__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 lb is larger than or equal to MaxSize and the resulting mask is equal to zero. Otherwise, zero. The pcmpestri instruction computes the bitmask, where bit0, bit1, bit2… in the mask correspond to the result of the operation on a0, a1, a2… in a.
Requirements
Intrinsic |
Architecture |
_mm_cmpestra |
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
#include <stdio.h>
#include <nmmintrin.h>
int main ()
{
__m128i a, b;
// NOTE: SIDD_LEAST_SIGNIFICANT sets the same bit as SIDD_BIT_MASK
const int mode = SIDD_UWORD_OPS | SIDD_CMP_EQUAL_EACH | SIDD_LEAST_SIGNIFICANT;
a.m128i_u16[7] = 0xCCCC;
a.m128i_u16[6] = 0xCCCC;
a.m128i_u16[5] = 0xCCCC;
a.m128i_u16[4] = 0xCCCC;
a.m128i_u16[3] = 0xCCCC;
a.m128i_u16[2] = 0xCCCC;
a.m128i_u16[1] = 0xCCCC;
a.m128i_u16[0] = 0xCCCC;
b.m128i_u16[7] = 0x3333;
b.m128i_u16[6] = 0x3333;
b.m128i_u16[5] = 0x3333;
b.m128i_u16[4] = 0x3333;
b.m128i_u16[3] = 0x3333;
b.m128i_u16[2] = 0x3333;
b.m128i_u16[1] = 0x3333;
b.m128i_u16[0] = 0x3333;
int returnValue = _mm_cmpestra(a, 8, b, -8, mode);
printf_s("_mm_cmpestra return value should be 1: %i\n", returnValue);
returnValue = _mm_cmpestrc(a, 8, b, 8, mode);
printf_s("_mm_cmpestrc return value should be 0: %i\n", returnValue);
a.m128i_u16[7] = 0x3333;
a.m128i_u16[5] = 0x3333;
returnValue = _mm_cmpestri(a, 8, b, 8, mode);
printf_s("_mm_cmpestri return value should be 5: %i\n", returnValue);
// NOTE: mode has SIDD_LEAST_SIGNIFICANT set which equals SIDD_BIT_MASK
__m128i fullResult = _mm_cmpestrm(a, 8, b, 8, mode);
printf_s("_mm_cmpestrm return value: 0x%016I64x 0x%016I64x\n",
fullResult.m128i_u64[1], fullResult.m128i_u64[0]);
returnValue = _mm_cmpestro(a, 8, b, 8, mode);
printf_s("_mm_cmpestro return value should be 0: %i\n", returnValue);
a.m128i_u16[0] = 0x3333;
returnValue = _mm_cmpestro(a, 8, b, 8, mode);
printf_s("_mm_cmpestro return value should be 1: %i\n", returnValue);
returnValue = _mm_cmpestrs(a, 8, b, 8, mode);
printf_s("_mm_cmpestrs return value should be 0: %i\n", returnValue);
returnValue = _mm_cmpestrs(a, 7, b, 8, mode);
printf_s("_mm_cmpestrs return value should be 1: %i\n", returnValue);
returnValue = _mm_cmpestrz(a, 8, b, 8, mode);
printf_s("_mm_cmpestrz return value should be 0: %i\n", returnValue);
returnValue = _mm_cmpestrz(a, 8, b, 7, mode);
printf_s("_mm_cmpestrz return value should be 1: %i\n", returnValue);
return 0;
}
_mm_cmpestra return value should be 1: 1
_mm_cmpestrc return value should be 0: 0
_mm_cmpestri return value should be 5: 5
_mm_cmpestrm return value: 0x0000000000000000 0x00000000000000a0
_mm_cmpestro return value should be 0: 0
_mm_cmpestro return value should be 1: 1
_mm_cmpestrs return value should be 0: 0
_mm_cmpestrs return value should be 1: 1
_mm_cmpestrz return value should be 0: 0
_mm_cmpestrz return value should be 1: 1