Function core::arch::x86::_mm_cmpestri

pub unsafe fn _mm_cmpestri<const IMM8: i32>(
    a: __m128i, 
    la: i32, 
    b: __m128i, 
    lb: i32
) -> i32

This is supported on x86 and target feature sse4.2 only.

Compares packed strings a and b with lengths la and lb using the control in IMM8 and return the generated index. Similar to _mm_cmpistri with the exception that _mm_cmpistri implicitly determines the length of a and b.

Control modes

The control specified by IMM8 may be one or more of the following.

Data size and signedness

• _SIDD_UBYTE_OPS - Default
• _SIDD_UWORD_OPS
• _SIDD_SBYTE_OPS
• _SIDD_SWORD_OPS

Comparison options

• _SIDD_CMP_EQUAL_ANY - Default
• _SIDD_CMP_RANGES
• _SIDD_CMP_EQUAL_EACH
• _SIDD_CMP_EQUAL_ORDERED

Result polarity

• _SIDD_POSITIVE_POLARITY - Default
• _SIDD_NEGATIVE_POLARITY

Bit returned

• _SIDD_LEAST_SIGNIFICANT - Default
• _SIDD_MOST_SIGNIFICANT

Examples

#[cfg(target_arch = "x86")]
use std::arch::x86::*;
#[cfg(target_arch = "x86_64")]
use std::arch::x86_64::*;


// The string we want to find a substring in
let haystack = b"Split \r\n\t line  ";

// The string we want to search for with some
// extra bytes we do not want to search for.
let needle = b"\r\n\t ignore this ";

let a = _mm_loadu_si128(needle.as_ptr() as *const _);
let b = _mm_loadu_si128(haystack.as_ptr() as *const _);

// Note: We explicitly specify we only want to search `b` for the
// first 3 characters of a.
let idx = _mm_cmpestri(a, 3, b, 15, _SIDD_CMP_EQUAL_ORDERED);

assert_eq!(idx, 6);

Intel’s documentation