eunomia 0.8.0

Atlas datatype law: the Single Source of Truth for numeric/scalar datatype vocabulary (scalars, complex, packed formats, conversions)
Documentation 
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use crate::convert::{widen_finite, widen_finite_high_word, widen_high_word};
use crate::types::{Bf16, Bf4, Bf8, F32, F4, F8};
use core::arch::x86_64::*;

/// # Safety
/// Callers must ensure the running CPU supports AVX-512 F, BW, and VL (the
/// dispatcher checks `has_avx512bw()`). Reads and writes stay within the shorter
/// of the two slices.
#[target_feature(enable = "avx512f,avx512bw,avx512vl")]
pub unsafe fn unpack_bf8_to_bf16(packed: &[Bf8], unpacked: &mut [Bf16]) {
    let len = packed.len().min(unpacked.len());
    let mut i = 0;

    static TABLE: [i32; 256] = {
        let mut table = [0i32; 256];
        let mut index = 0;
        while index < table.len() {
            table[index] = widen_high_word::<5, 2>(index as u32) as i32;
            index += 1;
        }
        table
    };

    while i + 16 <= len {
        let input = _mm_loadu_si128(packed.as_ptr().add(i) as *const __m128i);
        let indices = _mm512_cvtepu8_epi32(input);
        let gathered = _mm512_i32gather_epi32(indices, TABLE.as_ptr(), 4);
        let result = _mm512_cvtepi32_epi16(gathered);
        _mm256_storeu_si256(unpacked.as_mut_ptr().add(i) as *mut __m256i, result);
        i += 16;
    }

    for j in i..len {
        unpacked[j] = Bf16(widen_high_word::<5, 2>(u32::from(packed[j].0)));
    }
}

/// # Safety
/// Callers must ensure the running CPU supports AVX-512 F, BW, and VL (the
/// dispatcher checks `has_avx512bw()`). Reads and writes stay within the shorter
/// of the two slices.
#[target_feature(enable = "avx512f,avx512bw,avx512vl")]
pub unsafe fn unpack_bf4_to_bf16(packed: &[Bf4], unpacked: &mut [Bf16]) {
    let len = packed.len().min(unpacked.len());
    let mut i = 0;

    static TABLE_BITS: [u16; 16] = {
        let mut t = [0u16; 16];
        let mut idx = 0;
        while idx < 16 {
            t[idx] = widen_finite_high_word::<2, 1>(idx as u32);
            idx += 1;
        }
        t
    };
    // SAFETY: `[i16; 32]` and `__m512i` are both 64-byte plain-old-data with no
    // invalid bit patterns, so reinterpreting the array as the vector is sound.
    let table_zmm = core::mem::transmute::<[i16; 32], __m512i>([
        TABLE_BITS[0] as i16,
        TABLE_BITS[1] as i16,
        TABLE_BITS[2] as i16,
        TABLE_BITS[3] as i16,
        TABLE_BITS[4] as i16,
        TABLE_BITS[5] as i16,
        TABLE_BITS[6] as i16,
        TABLE_BITS[7] as i16,
        TABLE_BITS[8] as i16,
        TABLE_BITS[9] as i16,
        TABLE_BITS[10] as i16,
        TABLE_BITS[11] as i16,
        TABLE_BITS[12] as i16,
        TABLE_BITS[13] as i16,
        TABLE_BITS[14] as i16,
        TABLE_BITS[15] as i16,
        TABLE_BITS[0] as i16,
        TABLE_BITS[1] as i16,
        TABLE_BITS[2] as i16,
        TABLE_BITS[3] as i16,
        TABLE_BITS[4] as i16,
        TABLE_BITS[5] as i16,
        TABLE_BITS[6] as i16,
        TABLE_BITS[7] as i16,
        TABLE_BITS[8] as i16,
        TABLE_BITS[9] as i16,
        TABLE_BITS[10] as i16,
        TABLE_BITS[11] as i16,
        TABLE_BITS[12] as i16,
        TABLE_BITS[13] as i16,
        TABLE_BITS[14] as i16,
        TABLE_BITS[15] as i16,
    ]);

    while i + 32 <= len {
        let ptr = packed.as_ptr().add(i) as *const __m256i;
        let v_in = _mm256_loadu_si256(ptr);
        let v_u16 = _mm512_cvtepu8_epi16(v_in);
        let indices = _mm512_and_si512(v_u16, _mm512_set1_epi16(0x0f));

        let result = _mm512_permutexvar_epi16(indices, table_zmm);

        let out_ptr = unpacked.as_mut_ptr().add(i) as *mut __m512i;
        _mm512_storeu_si512(out_ptr, result);

        i += 32;
    }

    for j in i..len {
        let b = packed[j].0;
        unpacked[j] = Bf16(widen_finite_high_word::<2, 1>(b as u32));
    }
}

/// # Safety
/// Callers must ensure the running CPU supports AVX-512 F, BW, and VL (the
/// dispatcher checks `has_avx512bw()`). Reads and writes stay within the shorter
/// of the two slices.
#[target_feature(enable = "avx512f,avx512bw,avx512vl")]
pub unsafe fn unpack_bf4_to_bf16_packed(packed: &[u8], unpacked: &mut [Bf16]) {
    let len = packed.len();
    let n = len.min(unpacked.len() / 2);
    let mut i = 0;

    static TABLE_BITS: [u16; 16] = {
        let mut t = [0u16; 16];
        let mut idx = 0;
        while idx < 16 {
            t[idx] = widen_finite_high_word::<2, 1>(idx as u32);
            idx += 1;
        }
        t
    };

    let table_ymm = _mm256_loadu_si256(TABLE_BITS.as_ptr() as *const _);
    let mask_0f = _mm_set1_epi8(0x0F);

    while i + 16 <= n {
        let v = _mm_loadu_si128(packed.as_ptr().add(i) as *const _);

        let low_nibbles = _mm_and_si128(v, mask_0f);
        let high_nibbles = _mm_and_si128(_mm_srli_epi16(v, 4), mask_0f);

        let res_lo = _mm_unpacklo_epi8(low_nibbles, high_nibbles);
        let res_hi = _mm_unpackhi_epi8(low_nibbles, high_nibbles);

        let idx_lo = _mm256_cvtepu8_epi16(res_lo);
        let idx_hi = _mm256_cvtepu8_epi16(res_hi);

        let val_lo = _mm256_permutexvar_epi16(idx_lo, table_ymm);
        let val_hi = _mm256_permutexvar_epi16(idx_hi, table_ymm);

        _mm256_storeu_si256(unpacked.as_mut_ptr().add(2 * i) as *mut _, val_lo);
        _mm256_storeu_si256(unpacked.as_mut_ptr().add(2 * i + 16) as *mut _, val_hi);

        i += 16;
    }

    static TABLE: [Bf16; 16] = {
        let mut t = [Bf16(0); 16];
        let mut idx = 0;
        while idx < 16 {
            t[idx] = Bf16(TABLE_BITS[idx]);
            idx += 1;
        }
        t
    };
    for j in i..n {
        let byte = packed[j];
        unpacked[2 * j] = TABLE[(byte & 0x0F) as usize];
        unpacked[2 * j + 1] = TABLE[((byte >> 4) & 0x0F) as usize];
    }
}

/// # Safety
/// Callers must ensure the running CPU supports AVX-512 F and VL (the dispatcher
/// checks `has_avx512f()`). Reads and writes stay within the shorter of the two
/// slices.
#[target_feature(enable = "avx512f,avx512vl")]
pub unsafe fn unpack_f4_to_f32(packed: &[F4], unpacked: &mut [F32]) {
    let len = packed.len().min(unpacked.len());
    let mut i = 0;

    static TABLE_BITS: [u32; 16] = {
        let mut t = [0u32; 16];
        let mut idx = 0;
        while idx < 16 {
            t[idx] = widen_finite::<3, 0>(idx as u32);
            idx += 1;
        }
        t
    };

    let table_zmm = _mm512_loadu_si512(TABLE_BITS.as_ptr() as *const _);

    while i + 16 <= len {
        let ptr = packed.as_ptr().add(i) as *const __m128i;
        let v_in = _mm_loadu_si128(ptr);
        let v_u32 = _mm512_cvtepu8_epi32(v_in);
        let indices = _mm512_and_si512(v_u32, _mm512_set1_epi32(0x0f));

        let result = _mm512_permutexvar_epi32(indices, table_zmm);

        let out_ptr = unpacked.as_mut_ptr().add(i) as *mut f32;
        _mm512_storeu_si512(out_ptr as *mut _, result);
        i += 16;
    }

    for j in i..len {
        unpacked[j] = F32(f32::from_bits(TABLE_BITS[(packed[j].0 & 0x0f) as usize]));
    }
}

/// # Safety
/// Callers must ensure the running CPU supports AVX-512 F and VL (the dispatcher
/// checks `has_avx512f()`). Reads and writes stay within the shorter of the two
/// slices.
#[target_feature(enable = "avx512f,avx512vl")]
pub unsafe fn unpack_f4_to_f32_packed(packed: &[u8], unpacked: &mut [F32]) {
    let len = packed.len();
    let n = len.min(unpacked.len() / 2);
    let mut i = 0;

    static TABLE_BITS: [u32; 16] = {
        let mut t = [0u32; 16];
        let mut idx = 0;
        while idx < 16 {
            t[idx] = widen_finite::<3, 0>(idx as u32);
            idx += 1;
        }
        t
    };

    let table_zmm = _mm512_loadu_si512(TABLE_BITS.as_ptr() as *const _);
    let mask_0f = _mm_set1_epi8(0x0F);

    while i + 16 <= n {
        let v = _mm_loadu_si128(packed.as_ptr().add(i) as *const _);

        let low_nibbles = _mm_and_si128(v, mask_0f);
        let high_nibbles = _mm_and_si128(_mm_srli_epi16(v, 4), mask_0f);

        let res_lo = _mm_unpacklo_epi8(low_nibbles, high_nibbles);
        let res_hi = _mm_unpackhi_epi8(low_nibbles, high_nibbles);

        let idx_lo = _mm512_cvtepu8_epi32(res_lo);
        let idx_hi = _mm512_cvtepu8_epi32(res_hi);

        let val_lo = _mm512_permutexvar_epi32(idx_lo, table_zmm);
        let val_hi = _mm512_permutexvar_epi32(idx_hi, table_zmm);

        _mm512_storeu_si512(unpacked.as_mut_ptr().add(2 * i) as *mut _, val_lo);
        _mm512_storeu_si512(unpacked.as_mut_ptr().add(2 * i + 16) as *mut _, val_hi);

        i += 16;
    }

    static TABLE: [F32; 16] = {
        let mut t = [F32(0.0); 16];
        let mut idx = 0;
        while idx < 16 {
            t[idx] = F32(f32::from_bits(TABLE_BITS[idx]));
            idx += 1;
        }
        t
    };
    for j in i..n {
        let byte = packed[j];
        unpacked[2 * j] = TABLE[(byte & 0x0F) as usize];
        unpacked[2 * j + 1] = TABLE[((byte >> 4) & 0x0F) as usize];
    }
}

/// # Safety
/// Callers must ensure the running CPU supports AVX-512 F and VL (the dispatcher
/// checks `has_avx512f()`). Reads and writes stay within the shorter of the two
/// slices.
#[target_feature(enable = "avx512f,avx512vl")]
pub unsafe fn unpack_f8_to_f32(packed: &[F8], unpacked: &mut [F32]) {
    let len = packed.len().min(unpacked.len());
    let mut i = 0;

    static TABLE_BITS: [u32; 256] = {
        let mut t = [0u32; 256];
        let mut idx = 0;
        while idx < 256 {
            t[idx] = widen_finite::<4, 3>(idx as u32);
            idx += 1;
        }
        t
    };

    while i + 16 <= len {
        let ptr = packed.as_ptr().add(i) as *const __m128i;
        let v_in = _mm_loadu_si128(ptr);
        let v_u32 = _mm512_cvtepu8_epi32(v_in);

        let result = _mm512_i32gather_ps(v_u32, TABLE_BITS.as_ptr() as *const _, 4);

        let out_ptr = unpacked.as_mut_ptr().add(i) as *mut f32;
        _mm512_storeu_ps(out_ptr, result);
        i += 16;
    }

    for j in i..len {
        unpacked[j] = F32(f32::from_bits(TABLE_BITS[packed[j].0 as usize]));
    }
}