llama.cpp/ggml/src/ggml-vulkan/vulkan-shaders/dequant_q4_k.comp

#version 450

#include "dequant_head.comp"

layout(local_size_x = 32, local_size_y = 1, local_size_z = 1) in;

layout (binding = 0) readonly buffer A {A_TYPE data_a[];};
layout (binding = 1) writeonly buffer D {D_TYPE data_b[];};

void main() {
    [[unroll]] for (uint wgy = 0; wgy < 256; wgy++) {
        const uint i = gl_WorkGroupID.x * 256 + wgy;
        if (i >= p.M * p.K / QUANT_K) {
            return;
        }

        const uint tid = gl_LocalInvocationID.x;
        const uint il = tid / 8;
        const uint ir = tid % 8;
        const uint is = 2 * il;
        const uint n = 4;

        const FLOAT_TYPE dall = FLOAT_TYPE(data_a[i].d.x);
        const FLOAT_TYPE dmin = FLOAT_TYPE(data_a[i].d.y);

        const uint y_idx = i * QUANT_K + 64 * il + n * ir;
        const uint qs_idx = 32*il + n * ir;

        uint8_t sc;
        uint8_t m;
        if (is < 4) {
            sc = uint8_t(data_a[i].scales[is] & 63);
            m  = uint8_t(data_a[i].scales[is + 4] & 63);
        } else {
            sc = uint8_t((data_a[i].scales[is + 4] & 0xF) | ((data_a[i].scales[is - 4] >> 6) << 4));
            m  = uint8_t((data_a[i].scales[is + 4] >>  4) | ((data_a[i].scales[is    ] >> 6) << 4));
        }
        const FLOAT_TYPE d1 = dall * sc;
        const FLOAT_TYPE m1 = dmin * m;

        if (is < 4) {
            sc = uint8_t(data_a[i].scales[is + 1] & 63);
            m  = uint8_t(data_a[i].scales[is + 5] & 63);
        } else {
            sc = uint8_t((data_a[i].scales[is + 5] & 0xF) | ((data_a[i].scales[is - 3] >> 6) << 4));
            m  = uint8_t((data_a[i].scales[is + 5] >>  4) | ((data_a[i].scales[is + 1] >> 6) << 4));
        }
        const FLOAT_TYPE d2 = dall * sc;
        const FLOAT_TYPE m2 = dmin * m;

        [[unroll]] for (uint l = 0; l < n; ++l) {
            data_b[y_idx + l     ] = D_TYPE(d1 * FLOAT_TYPE(data_a[i].qs[qs_idx + l] & 0xF) - m1);
            data_b[y_idx + l + 32] = D_TYPE(d2 * FLOAT_TYPE(data_a[i].qs[qs_idx + l] >>  4) - m2);
        }
    }
}