mojo simd

simd.c

#include <stdio.h>
#include <x86intrin.h>

// gcc -msse4.1 -O0 -o program program.c
int main() {
    __m128i A = _mm_set_epi32(4, 3, 2, 1);
    __m128i B = _mm_set_epi32(8, 7, 6, 5);
    __m128i Cond = _mm_set_epi32(0, -1, -1, 0);

    __m128i Result = _mm_blendv_epi8(A, B, Cond);

    int result[4];
    _mm_storeu_si128((__m128i*)result, Result);
    printf("Result: %d %d %d %d\n", result[0], result[1], result[2], result[3]);

    return 0;
}

simd.mojo

import math

fn main():
    let a = math.iota[DType.int32, 4](1)
    let b = math.iota[DType.int32, 4](5)
    let mask = SIMD[DType.bool, 4](True, False, False, True)
    let c = mask.select(a, b)
    print(c)

utf8_count.mojo

# https://mzaks.medium.com/counting-chars-with-simd-in-mojo-140ee730bd4d
from algorithm import vectorize

fn utf8_count(s: StringLiteral) -> Int:
    alias simd_width_u8 = simdwidthof[DType.uint8]()

    let p = s.data().bitcast[DType.uint8]()
    let string_bytes_length = len(s)
    var result = 0

    @parameter
    fn count[simd_width: Int](offset: Int):
        result += ((p.simd_load[simd_width](offset) >> 6) != 0b10).cast[DType.uint8]().reduce_add().to_int()
    
    vectorize[simd_width_u8, count](string_bytes_length)
        
    return result

fn main():
    print(utf8_count("你好，世界"))