llama-cpp-sys-4 0.2.37

#pragma clang diagnostic ignored "-Wgnu-zero-variadic-macro-arguments"
#pragma clang diagnostic ignored "-Wunused-function"
#pragma clang diagnostic ignored "-Wunused-variable"
#pragma clang diagnostic ignored "-Wunused-but-set-variable"

#include <assert.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>

#include <HAP_farf.h>
#include <HAP_compute_res.h>

#define GGML_COMMON_DECL_C
#include "ggml-common.h"

#include "hex-dma.h"
#include "hvx-utils.h"
#include "hvx-dump.h"
#include "worker-pool.h"
#include "htp-ctx.h"
#include "htp-msg.h"

#include "hmx-utils.h"
#include "hmx-ops.h"
#include "hmx-profile.h"

static const __fp16 q4_0_to_fp16_lut[64] __attribute__((aligned(VLEN))) = {
    -8, 0, -7, 0, -6, 0, -5, 0, -4, 0, -3, 0, -2, 0, -1, 0, 0, 0, 1, 0, 2, 0, 3, 0, 4, 0, 5, 0, 6, 0, 7, 0,
};

// MXFP4 dequantization LUT: maps 4-bit index to fp16 mantissa value
// kvalues: 0, 0.5, 1, 1.5, 2, 3, 4, 6, 0, -0.5, -1, -1.5, -2, -3, -4, -6
static const __fp16 mxfp4_to_fp16_lut[64] __attribute__((aligned(VLEN))) = {
    0, 0, 0.5, 0, 1, 0, 1.5, 0, 2, 0, 3, 0, 4, 0, 6, 0, 0, 0, -0.5, 0, -1, 0, -1.5, 0, -2, 0, -3, 0, -4, 0, -6, 0,
};

static const __fp16 iq4_nl_to_fp16_lut[64] __attribute__((aligned(VLEN))) = {
    -127, 0, -104, 0, -83, 0, -65, 0, -49, 0, -35, 0, -22, 0, -10, 0,
    1,    0, 13,   0, 25,  0, 38,  0, 53,  0, 69,  0, 89,  0, 113, 0,
};

// vscatter offsets for fused dequant+transpose: write K-values directly to [K][N] tile.
// word[i] = i*128 maps K-row-pair i to byte offset i*128 in the tile.
// Column offset (n*4) is added at runtime.  Only entries 0..15 are used (masked by predicate).
static const int32_t weight_transpose_scatter_offsets[32] __attribute__((aligned(VLEN))) = {
    0*128,  1*128,  2*128,  3*128,  4*128,  5*128,  6*128,  7*128,
    8*128,  9*128, 10*128, 11*128, 12*128, 13*128, 14*128, 15*128,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};

// Scales per x4x2 logical block: 8 × sizeof(__fp16) = 16 bytes
#define HMX_X4X2_SCALES_PER_BLK  8
#define HMX_X4X2_DBLK_SIZE       16  // 8 * 2 bytes (fp16 scales for Q4_0/Q8_0/IQ4_NL)
#define HMX_X4X2_MXFP4_EBLK_SIZE 8   // 8 * 1 byte  (E8M0 scales for MXFP4)

static inline void swap_ptr(void **p1, void **p2) {
    void *t = *p1;
    *p1     = *p2;
    *p2     = t;
}

typedef struct {
    uint8_t       *dst;
    const uint8_t *src;
    dma_queue     *dma;
    size_t         n_rows;
    size_t         src_stride;   // DDR row stride (full row_stride)
    size_t         dst_stride;   // VTCM sub-block row stride
    size_t         quant_off;    // quant byte offset in each DDR row
    size_t         quant_width;  // quant bytes to copy per row
    size_t         scale_off;    // scale byte offset in each DDR row
    size_t         scale_width;  // scale bytes to copy per row
} qweight_fetch_task_state_t;

// Compute the byte stride of one row in x4x2 format.
// Numerically equals ggml_row_size(type, k) when k is 256-aligned, because
// x4x2 packing has the same density as block_q4_0 / block_q8_0.
// Layout per row: [quants: nb*128 (Q4) or nb*256 (Q8)][scales: nb*16 bytes]
// Total per row = nb * (128+16) = 144*nb (Q4) or nb * (256+16) = 272*nb (Q8).
// Callers must ensure k is a multiple of 256 (enforced by proc_hmx_matmul_req).
static inline size_t get_x4x2_row_stride(int weight_type, int k) {
    int nb = (k + QK_Q4_0x4x2 - 1) / QK_Q4_0x4x2;
    switch (weight_type) {
        case HTP_TYPE_Q4_0:
        case HTP_TYPE_IQ4_NL:
            return (size_t) nb * (QK_Q4_0x4x2 / 2 + HMX_X4X2_DBLK_SIZE);         // 144 * nb
        case HTP_TYPE_Q8_0:
            return (size_t) nb * (QK_Q8_0x4x2 + HMX_X4X2_DBLK_SIZE);             // 272 * nb
        case HTP_TYPE_MXFP4:
            return (size_t) nb * (QK_MXFP4x4x2 / 2 + HMX_X4X2_MXFP4_EBLK_SIZE);  // 136 * nb
        default:
            return 0;
    }
}

// --- Overflow-safe arithmetic for VTCM budget calculation ---

static inline bool hmx_mul_overflow(size_t a, size_t b, size_t *out) {
    if (a != 0 && b > SIZE_MAX / a) return true;
    *out = a * b;
    return false;
}

static inline bool hmx_add_overflow(size_t a, size_t b, size_t *out) {
    if (a > SIZE_MAX - b) return true;
    *out = a + b;
    return false;
}

// Search for optimal (mc, nc) chunk sizes that maximize mc * nc within VTCM budget.
//
// Cost model: total = nc * per_n_cost + mc * per_m_cost + mc * nc * per_mn_cost + overhead
//   per_n_cost:  bytes per nc column (weight + scratch buffers)
//   per_m_cost:  bytes per mc row (activation)
//   per_mn_cost: bytes per mc*nc element (output)
//   overhead:    fixed bytes (scales 256B, eye_tile 2048B, etc.)
//
// Algorithm: nc sweeps from n_max down by 32, analytically solving for mc_max.
// Returns 0 on success, -1 if VTCM is insufficient.
static int hmx_compute_chunks(
    size_t vtcm_total, size_t overhead,
    size_t per_n_cost, size_t per_m_cost, size_t per_mn_cost,
    int m, int n,
    size_t *m_chunk_out, size_t *n_chunk_out,
    size_t *total_out)
{
    if (m <= 0 || n <= 0) return -1;
    if (vtcm_total <= overhead) return -1;
    if (per_n_cost == 0 || per_m_cost == 0 || per_mn_cost == 0) return -1;

    const size_t usable = vtcm_total - overhead;
    size_t best_mn = 0, best_m = 0, best_n = 0;

    const size_t n_max = hex_align_down((size_t)n, HMX_FP16_TILE_N_COLS);
    for (size_t nc = n_max; nc >= HMX_FP16_TILE_N_COLS; nc -= HMX_FP16_TILE_N_COLS) {
        // Early exit: if nc * m_max cannot beat best, smaller nc won't either
        if (nc * hex_align_down((size_t)m, HMX_FP16_TILE_N_ROWS) <= best_mn)
            break;

        size_t n_fixed = 0, ncmn = 0, mc_denom = 0;
        if (hmx_mul_overflow(nc, per_n_cost, &n_fixed)) continue;
        if (n_fixed >= usable) goto next_nc;

        if (hmx_mul_overflow(nc, per_mn_cost, &ncmn)) goto next_nc;
        if (hmx_add_overflow(per_m_cost, ncmn, &mc_denom) || mc_denom == 0) goto next_nc;

        {
            size_t remain = usable - n_fixed;
            size_t mc = remain / mc_denom;
            mc = hex_align_down(mc, HMX_FP16_TILE_N_ROWS);
            mc = hex_smin(mc, (size_t)m);

            if (mc > 0 && mc * nc > best_mn) {
                best_mn = mc * nc;
                best_m  = mc;
                best_n  = nc;
            }
        }

next_nc:
        if (nc == HMX_FP16_TILE_N_COLS) break;  // avoid size_t underflow
    }

    if (best_m == 0 || best_n == 0) return -1;

    // Compute exact total (with overflow checks)
    size_t t0 = 0, t1 = 0, t2 = 0, mn = 0, total = 0;
    if (hmx_mul_overflow(best_n, per_n_cost, &t0)) return -1;
    if (hmx_mul_overflow(best_m, per_m_cost, &t1)) return -1;
    if (hmx_mul_overflow(best_m, best_n, &mn)) return -1;
    if (hmx_mul_overflow(mn, per_mn_cost, &t2)) return -1;
    if (hmx_add_overflow(t0, t1, &total)) return -1;
    if (hmx_add_overflow(total, t2, &total)) return -1;
    if (hmx_add_overflow(total, overhead, &total)) return -1;

    *m_chunk_out = best_m;
    *n_chunk_out = best_n;
    *total_out   = total;
    return 0;
}

// forward declaration – defined after transfer_activation_chunk_fp32_to_fp16
void transfer_activation_chunk_threaded(struct htp_context *ctx, __fp16 *dst, const float *src, int n_rows, int k_block, int k_stride);

// Scatter row-major FP16 weight (already in VTCM scratch) directly into transposed [K][N] tiles.
// vtcm_src: [n_cols][k] row-major fp16 in VTCM scratch buffer
// vtcm_dst: [n_col_tiles][n_k_tiles][HMX_FP16_TILE_N_ELMS] tile-major interleaved fp16
static void interleave_fp16_weight_chunk_to_tiles(__fp16 *restrict vtcm_dst,
                                                   const __fp16 *restrict vtcm_src,
                                                   int n_cols, int k) {
    assert(n_cols % HMX_FP16_TILE_N_COLS == 0);
    assert(k % HMX_FP16_TILE_N_COLS == 0);

    const int n_k_tiles = k / HMX_FP16_TILE_N_COLS;
    const HVX_Vector v_scat_base = hvx_vmem(weight_transpose_scatter_offsets);
    const HVX_Vector v_scat_step = Q6_V_vsplat_R(4);
    const HVX_VectorPred q_mask64 = Q6_Q_vsetq_R(64);

    for (int r = 0; r < n_cols; r += 2) {
        int ct = r / HMX_FP16_TILE_N_ROWS;       // N-dimension tile index
        int local_r = r % HMX_FP16_TILE_N_ROWS;  // intra-tile row index
        const bool next_row_valid = (r + 1) < n_cols;

        // Offset vectors for N-columns local_r and local_r+1, reused across K-tiles.
        HVX_Vector v_off0 = Q6_Vw_vadd_VwVw(v_scat_base, Q6_V_vsplat_R(local_r * 4));
        HVX_Vector v_off1 = Q6_Vw_vadd_VwVw(v_off0, v_scat_step);

        for (int c = 0; c < k; c += HMX_FP16_TILE_N_COLS) {
            int kt       = c / HMX_FP16_TILE_N_COLS;
            int tile_idx = ct * n_k_tiles + kt;
            __fp16 *tile_base = vtcm_dst + tile_idx * HMX_FP16_TILE_N_ELMS;

            HVX_Vector v0 = hvx_vmemu(vtcm_src + r * k + c);
            HVX_Vector v1 = next_row_valid ? hvx_vmemu(vtcm_src + (r + 1) * k + c) : Q6_V_vzero();

            Q6_vscatter_QRMVwV(q_mask64, (size_t)tile_base, HMX_FP16_TILE_SIZE - 1, v_off0, v0);
            Q6_vscatter_QRMVwV(q_mask64, (size_t)tile_base, HMX_FP16_TILE_SIZE - 1, v_off1, v1);
        }
    }
}

// --- x4x2 format dequantizers ---

// Dequantize one x4x2 Q4_0 group (32 elements from 32 packed bytes) -> 32 FP16 in first 64 bytes.
// In x4x2, sub-blocks 0..3 use lower nibbles, sub-blocks 4..7 use upper nibbles
// of the same 32 packed bytes.
static inline HVX_Vector dequantize_x4x2_q4_0_group_hvx(
         const uint8_t *packed_32, bool upper_nibbles,
         const __fp16 *scale, const HVX_Vector vlut_cvt) {
    HVX_Vector vq = hvx_vmemu(packed_32);
    const HVX_Vector mask_h4 = Q6_Vb_vsplat_R(0x0F);
    HVX_Vector v_scales = hvx_vec_splat_f16(*scale);
    // q4x4x2 stores two int4 values per byte. Keep only the selected nibble.
    HVX_Vector v_quants = upper_nibbles ? Q6_Vub_vlsr_VubR(vq, 4) : vq;
    v_quants = Q6_V_vand_VV(v_quants, mask_h4);
    // Shuffle before LUT
    v_quants = Q6_Vb_vshuff_Vb(v_quants);
    // Use standard vlut16 (not _nomatch) to avoid stale-register NaN.
    // _nomatch retains the previous destination-register value for colliding
    // indices, but the C intrinsic doesn't model the implicit read so the
    // compiler may allocate a register containing garbage/NaN.
    HVX_VectorPair vp = Q6_Wh_vlut16_VbVhR(v_quants, vlut_cvt, 0);
    HVX_Vector v_hf = Q6_V_lo_W(vp);

    return Q6_Vhf_equals_Vqf16(Q6_Vqf16_vmpy_VhfVhf(v_hf, v_scales));
}

// Batch-dequantize 4 contiguous x4x2 Q4_0 groups (4x32 = 128 packed bytes) using
// full HVX vector width.  One vmemu + one vlut16 replaces 4 separate calls.
// Output: out[0..3] each hold 32 FP16 values in the first 64 bytes.
static inline void dequantize_x4x2_q4_0_x4groups_hvx(
            const uint8_t *packed_128, bool upper_nibbles,
            const __fp16 *scales_4, const HVX_Vector vlut_cvt,
            HVX_Vector out[4]) {
    // Load all 128 packed bytes (4 contiguous 32-byte groups)
    HVX_Vector vq = hvx_vmemu(packed_128);
    const HVX_Vector mask_h4 = Q6_Vb_vsplat_R(0x0F);
    HVX_Vector v_quants = upper_nibbles ? Q6_Vub_vlsr_VubR(vq, 4) : vq;
    v_quants = Q6_V_vand_VV(v_quants, mask_h4);

    // Shuffle before LUT
    v_quants = Q6_Vb_vshuff_Vb(v_quants);

    // Full-width vlut16: 128 byte lookups -> 128 fp16 results in a VectorPair
    HVX_VectorPair vp = Q6_Wh_vlut16_VbVhR(v_quants, vlut_cvt, 0);
    HVX_Vector v_lo = Q6_V_lo_W(vp);  // [group0: 32 fp16 | group1: 32 fp16]
    HVX_Vector v_hi = Q6_V_hi_W(vp);  // [group2: 32 fp16 | group3: 32 fp16]

    // Build per-group scale vectors: first 64 bytes use scale_a, last 64 use scale_b
    HVX_VectorPred q64 = Q6_Q_vsetq_R(64);
    HVX_Vector v_sc01 = Q6_V_vmux_QVV(q64, hvx_vec_splat_f16(scales_4[0]), hvx_vec_splat_f16(scales_4[1]));
    HVX_Vector v_sc23 = Q6_V_vmux_QVV(q64, hvx_vec_splat_f16(scales_4[2]), hvx_vec_splat_f16(scales_4[3]));

    v_lo = Q6_Vhf_equals_Vqf16(Q6_Vqf16_vmpy_VhfVhf(v_lo, v_sc01));
    v_hi = Q6_Vhf_equals_Vqf16(Q6_Vqf16_vmpy_VhfVhf(v_hi, v_sc23));

    // Extract individual groups: scatter uses q_mask64 so only first 64 bytes matter
    out[0] = v_lo;                      // group0 already in [0:63]
    out[1] = Q6_V_vror_VR(v_lo, 64);    // group1 rotated to [0:63]
    out[2] = v_hi;                      // group2 already in [0:63]
    out[3] = Q6_V_vror_VR(v_hi, 64);    // group3 rotated to [0:63]
}

// Dequantize one x4x2 Q8_0 group (32 int8 quants) -> 32 FP16 in first 64 bytes.
static inline HVX_Vector dequantize_x4x2_q8_0_group_hvx(
        const int8_t *quants_32, const __fp16 *scale) {
    HVX_Vector vq = hvx_vmemu(quants_32);
    HVX_Vector v_scales = hvx_vec_splat_f16(*scale);
    HVX_Vector v0 = Q6_V_lo_W(Q6_Wh_vunpack_Vb(vq));
    HVX_Vector v_hf = Q6_Vhf_equals_Vh(v0);
    return Q6_Vhf_equals_Vqf16(Q6_Vqf16_vmpy_VhfVhf(v_hf, v_scales));
}

// --- MXFP4 E8M0 scale conversion and dequantization ---
//
// HVX batch-convert 8 E8M0 bytes (one x4x2 block's scales) to __fp16[8] on stack.
// Scalar loads from the stack array execute on the scalar pipeline, in parallel
// with HVX vlut16/vmpy/vscatter — freeing HVX slots in the hot loop.
// Arithmetic: fp16_bits = clamp(e - 112, 0, 30) << 10
// e=0..112 -> 0 (underflow), e=113..142 -> valid fp16, e>=143 -> clamped to 2^15.

typedef struct {
    __fp16 v[8] __attribute__((aligned(16)));
} mxfp4_scales_t;

static inline mxfp4_scales_t mxfp4_convert_scales(const uint8_t * e8m0_8) {
    mxfp4_scales_t s;
    HVX_Vector     v  = hvx_vmemu(e8m0_8);
    HVX_Vector     vh = Q6_V_lo_W(Q6_Wuh_vunpack_Vub(v));
    vh                = Q6_Vh_vsub_VhVh(vh, Q6_Vh_vsplat_R(112));
    vh                = Q6_Vh_vmax_VhVh(vh, Q6_V_vzero());
    vh                = Q6_Vh_vmin_VhVh(vh, Q6_Vh_vsplat_R(30));
    vh                = Q6_Vh_vasl_VhR(vh, 10);
    hvx_vec_store_u(s.v, 16, vh);
    return s;
}

static inline HVX_Vector mxfp4_extract_splat(mxfp4_scales_t scales, int idx) {
    return hvx_vec_splat_f16(scales.v[idx]);
}

// Dequantize one x4x2 MXFP4 group (32 elements from 32 packed bytes) -> 32 FP16.
static inline HVX_Vector dequantize_x4x2_mxfp4_group_hvx(const uint8_t *  packed_32,
                                                         bool             upper_nibbles,
                                                         int              sub_blk,
                                                         const HVX_Vector vlut_cvt,
                                                         mxfp4_scales_t   scales) {
    HVX_Vector       vq       = hvx_vmemu(packed_32);
    const HVX_Vector mask_h4  = Q6_Vb_vsplat_R(0x0F);
    HVX_Vector       v_quants = upper_nibbles ? Q6_Vub_vlsr_VubR(vq, 4) : vq;
    v_quants                  = Q6_V_vand_VV(v_quants, mask_h4);

    HVX_Vector v_sc = mxfp4_extract_splat(scales, sub_blk);

    v_quants            = Q6_Vb_vshuff_Vb(v_quants);
    HVX_VectorPair vp   = Q6_Wh_vlut16_VbVhR(v_quants, vlut_cvt, 0);
    HVX_Vector     v_hf = Q6_V_lo_W(vp);

    return Q6_Vhf_equals_Vqf16(Q6_Vqf16_vmpy_VhfVhf(v_hf, v_sc));
}

// Batch-dequantize 4 contiguous x4x2 MXFP4 groups (4x32 = 128 packed bytes).
static inline void dequantize_x4x2_mxfp4_x4groups_hvx(const uint8_t *  packed_128,
                                                      bool             upper_nibbles,
                                                      int              sub_blk_base,
                                                      const HVX_Vector vlut_cvt,
                                                      mxfp4_scales_t   scales,
                                                      HVX_Vector       out[4]) {
    HVX_Vector       vq       = hvx_vmemu(packed_128);
    const HVX_Vector mask_h4  = Q6_Vb_vsplat_R(0x0F);
    HVX_Vector       v_quants = upper_nibbles ? Q6_Vub_vlsr_VubR(vq, 4) : vq;
    v_quants                  = Q6_V_vand_VV(v_quants, mask_h4);

    v_quants = Q6_Vb_vshuff_Vb(v_quants);

    HVX_VectorPair vp   = Q6_Wh_vlut16_VbVhR(v_quants, vlut_cvt, 0);
    HVX_Vector     v_lo = Q6_V_lo_W(vp);
    HVX_Vector     v_hi = Q6_V_hi_W(vp);

    HVX_VectorPred q64    = Q6_Q_vsetq_R(64);
    HVX_Vector     v_sc01 = Q6_V_vmux_QVV(q64, mxfp4_extract_splat(scales, sub_blk_base + 0),
                                          mxfp4_extract_splat(scales, sub_blk_base + 1));
    HVX_Vector     v_sc23 = Q6_V_vmux_QVV(q64, mxfp4_extract_splat(scales, sub_blk_base + 2),
                                          mxfp4_extract_splat(scales, sub_blk_base + 3));

    v_lo = Q6_Vhf_equals_Vqf16(Q6_Vqf16_vmpy_VhfVhf(v_lo, v_sc01));
    v_hi = Q6_Vhf_equals_Vqf16(Q6_Vqf16_vmpy_VhfVhf(v_hi, v_sc23));

    out[0] = v_lo;
    out[1] = Q6_V_vror_VR(v_lo, 64);
    out[2] = v_hi;
    out[3] = Q6_V_vror_VR(v_hi, 64);
}

// Dequantize a tile range from x4x2 weight data (already in VTCM) to tile-major FP16.
// Input:  vtcm_src has n_cols rows of x4x2 data, each row_stride bytes.
// Output: vtcm_dst in tile-major FP16 layout.
static void dequantize_x4x2_weight_to_fp16_tiles_task(
        __fp16 *restrict vtcm_dst,
        const uint8_t *restrict vtcm_src,
        int n_cols, int k_block,
        size_t row_stride, int weight_type,
        int start_tile, int end_tile) {

    const int n_k_tiles = k_block / HMX_FP16_TILE_N_COLS;
    const int qrow_size = (weight_type == HTP_TYPE_Q8_0) ? k_block : (k_block / 2);

    const HVX_Vector vlut_cvt = (weight_type == HTP_TYPE_IQ4_NL) ? hvx_vmem(iq4_nl_to_fp16_lut) :
                                (weight_type == HTP_TYPE_MXFP4)  ? hvx_vmem(mxfp4_to_fp16_lut) :
                                                                   hvx_vmem(q4_0_to_fp16_lut);

    // vscatter setup: write dequantized K-values directly to transposed [K][N] tile positions.
    // Each int32 element holds a K-row-pair (2 adjacent fp16 values).  word[i] at offset i*128
    // maps to K-rows 2i and 2i+1.  Column offset (n*4) added per row.
    const HVX_Vector v_scat_base = hvx_vmem(weight_transpose_scatter_offsets);
    const HVX_Vector v_scat_step = Q6_V_vsplat_R(4);  // 4 bytes = 1 column step
    const HVX_VectorPred q_mask64 = Q6_Q_vsetq_R(64);  // first 16 words (64 bytes)

    for (int t = start_tile; t < end_tile; ) {
        int ct = t / n_k_tiles;  // column tile index
        int kt = t % n_k_tiles;  // K tile index

        // --- Batch-4 fast path for Q4_0/IQ4_NL: process 4 contiguous K-tiles with one vlut16 per row ---
        if ((weight_type == HTP_TYPE_Q4_0 || weight_type == HTP_TYPE_IQ4_NL) && (kt % 4 == 0) && (t + 4 <= end_tile) &&
            ((t + 3) / n_k_tiles == ct)) {
            int blk_idx      = (kt * 32) / QK_Q4_0x4x2;
            int sub_blk_base = ((kt * 32) % QK_Q4_0x4x2) / 32;  // 0 or 4
            bool upper       = (sub_blk_base >= 4);
            int packed_off   = blk_idx * (QK_Q4_0x4x2 / 2);     // 128 contiguous packed bytes
            int scale_off    = qrow_size + blk_idx * HMX_X4X2_DBLK_SIZE
                             + sub_blk_base * (int)sizeof(__fp16);   // 4 consecutive scales

            __fp16 *tile_bases[4];
            for (int g = 0; g < 4; g++) { tile_bases[g] = vtcm_dst + (t + g) * HMX_FP16_TILE_N_ELMS; }

            HVX_Vector v_off = v_scat_base;
            for (int r = 0; r < HMX_FP16_TILE_N_ROWS; r += 2) {
                int row0 = ct * HMX_FP16_TILE_N_COLS + r;
                int row1 = row0 + 1;
                const uint8_t *r0 = vtcm_src + row0 * row_stride;
                const uint8_t *r1 = vtcm_src + row1 * row_stride;

                HVX_Vector v0[4], v1[4];
                dequantize_x4x2_q4_0_x4groups_hvx(r0 + packed_off, upper, (const __fp16 *)(r0 + scale_off), vlut_cvt, v0);
                if (row1 < n_cols) {
                    dequantize_x4x2_q4_0_x4groups_hvx(r1 + packed_off, upper, (const __fp16 *)(r1 + scale_off), vlut_cvt, v1);
                } else {
                    v1[0] = v1[1] = v1[2] = v1[3] = Q6_V_vzero();
                }

                for (int g = 0; g < 4; g++) { Q6_vscatter_QRMVwV(q_mask64, (size_t)tile_bases[g], HMX_FP16_TILE_SIZE - 1, v_off, v0[g]); }
                v_off = Q6_Vw_vadd_VwVw(v_off, v_scat_step);
                for (int g = 0; g < 4; g++) { Q6_vscatter_QRMVwV(q_mask64, (size_t)tile_bases[g], HMX_FP16_TILE_SIZE - 1, v_off, v1[g]); }
                v_off = Q6_Vw_vadd_VwVw(v_off, v_scat_step);
            }

            for (int g = 0; g < 4; g++) { (void) *(volatile HVX_Vector *)(tile_bases[g]); }

            t += 4;
            continue;
        }

        // --- Batch-4 fast path for MXFP4: same nibble layout but E8M0 scales ---
        if (weight_type == HTP_TYPE_MXFP4 && (kt % 4 == 0) && (t + 4 <= end_tile) && ((t + 3) / n_k_tiles == ct)) {
            int  blk_idx      = (kt * 32) / QK_MXFP4x4x2;
            int  sub_blk_base = ((kt * 32) % QK_MXFP4x4x2) / 32;                 // 0 or 4
            bool upper        = (sub_blk_base >= 4);
            int  packed_off   = blk_idx * (QK_MXFP4x4x2 / 2);                    // 128 contiguous packed bytes
            int  e8m0_blk_off = qrow_size + blk_idx * HMX_X4X2_MXFP4_EBLK_SIZE;  // all 8 E8M0 scales

            __fp16 * tile_bases[4];
            for (int g = 0; g < 4; g++) {
                tile_bases[g] = vtcm_dst + (t + g) * HMX_FP16_TILE_N_ELMS;
            }

            HVX_Vector v_off = v_scat_base;
            for (int r = 0; r < HMX_FP16_TILE_N_ROWS; r += 2) {
                int             row0 = ct * HMX_FP16_TILE_N_COLS + r;
                int             row1 = row0 + 1;
                const uint8_t * r0   = vtcm_src + row0 * row_stride;
                const uint8_t * r1   = vtcm_src + row1 * row_stride;

                // Batch-convert all 8 E8M0 scales once per row (stays in HVX register)
                mxfp4_scales_t r0_e8 = mxfp4_convert_scales(r0 + e8m0_blk_off);

                HVX_Vector v0[4], v1[4];
                dequantize_x4x2_mxfp4_x4groups_hvx(r0 + packed_off, upper, sub_blk_base, vlut_cvt, r0_e8, v0);
                if (row1 < n_cols) {
                    mxfp4_scales_t r1_e8 = mxfp4_convert_scales(r1 + e8m0_blk_off);
                    dequantize_x4x2_mxfp4_x4groups_hvx(r1 + packed_off, upper, sub_blk_base, vlut_cvt, r1_e8, v1);
                } else {
                    v1[0] = v1[1] = v1[2] = v1[3] = Q6_V_vzero();
                }

                for (int g = 0; g < 4; g++) {
                    Q6_vscatter_QRMVwV(q_mask64, (size_t) tile_bases[g], HMX_FP16_TILE_SIZE - 1, v_off, v0[g]);
                }
                v_off = Q6_Vw_vadd_VwVw(v_off, v_scat_step);
                for (int g = 0; g < 4; g++) {
                    Q6_vscatter_QRMVwV(q_mask64, (size_t) tile_bases[g], HMX_FP16_TILE_SIZE - 1, v_off, v1[g]);
                }
                v_off = Q6_Vw_vadd_VwVw(v_off, v_scat_step);
            }

            for (int g = 0; g < 4; g++) {
                (void) *(volatile HVX_Vector *) (tile_bases[g]);
            }

            t += 4;
            continue;
        }

        // --- Single-tile fallback ---
        __fp16 *tile_base = vtcm_dst + t * HMX_FP16_TILE_N_ELMS;

        if (weight_type == HTP_TYPE_Q4_0 || weight_type == HTP_TYPE_IQ4_NL) {
            int blk_idx  = (kt * 32) / QK_Q4_0x4x2;
            int sub_blk  = ((kt * 32) % QK_Q4_0x4x2) / 32;
            bool upper   = (sub_blk >= 4);
            int byte_off  = blk_idx * (QK_Q4_0x4x2 / 2) + (upper ? (sub_blk - 4) : sub_blk) * 32;
            int scale_off = qrow_size + blk_idx * HMX_X4X2_DBLK_SIZE + sub_blk * (int)sizeof(__fp16);

            HVX_Vector v_off = v_scat_base;  // reset to column 0
            for (int r = 0; r < HMX_FP16_TILE_N_ROWS; r += 2) {
                int row0 = ct * HMX_FP16_TILE_N_COLS + r;
                int row1 = row0 + 1;

                const uint8_t *r0 = vtcm_src + row0 * row_stride;
                const uint8_t *r1 = vtcm_src + row1 * row_stride;

                HVX_Vector v0 = dequantize_x4x2_q4_0_group_hvx(
                    r0 + byte_off, upper, (const __fp16 *)(r0 + scale_off), vlut_cvt);
                HVX_Vector v1 = (row1 < n_cols)
                    ? dequantize_x4x2_q4_0_group_hvx(
                        r1 + byte_off, upper, (const __fp16 *)(r1 + scale_off), vlut_cvt)
                    : Q6_V_vzero();

                Q6_vscatter_QRMVwV(q_mask64, (size_t)tile_base, HMX_FP16_TILE_SIZE - 1, v_off, v0);
                v_off = Q6_Vw_vadd_VwVw(v_off, v_scat_step);
                Q6_vscatter_QRMVwV(q_mask64, (size_t)tile_base, HMX_FP16_TILE_SIZE - 1, v_off, v1);
                v_off = Q6_Vw_vadd_VwVw(v_off, v_scat_step);
            }
            (void) *(volatile HVX_Vector *)(tile_base);
        } else if (weight_type == HTP_TYPE_MXFP4) {
            int  blk_idx      = (kt * 32) / QK_MXFP4x4x2;
            int  sub_blk      = ((kt * 32) % QK_MXFP4x4x2) / 32;
            bool upper        = (sub_blk >= 4);
            int  byte_off     = blk_idx * (QK_MXFP4x4x2 / 2) + (upper ? (sub_blk - 4) : sub_blk) * 32;
            int  e8m0_blk_off = qrow_size + blk_idx * HMX_X4X2_MXFP4_EBLK_SIZE;

            HVX_Vector v_off = v_scat_base;
            for (int r = 0; r < HMX_FP16_TILE_N_ROWS; r += 2) {
                int row0 = ct * HMX_FP16_TILE_N_COLS + r;
                int row1 = row0 + 1;

                const uint8_t * r0 = vtcm_src + row0 * row_stride;
                const uint8_t * r1 = vtcm_src + row1 * row_stride;

                // Batch-convert all 8 E8M0 scales once per row (stays in HVX register)
                mxfp4_scales_t r0_e8 = mxfp4_convert_scales(r0 + e8m0_blk_off);

                HVX_Vector v0 = dequantize_x4x2_mxfp4_group_hvx(r0 + byte_off, upper, sub_blk, vlut_cvt, r0_e8);
                HVX_Vector v1;
                if (row1 < n_cols) {
                    mxfp4_scales_t r1_e8 = mxfp4_convert_scales(r1 + e8m0_blk_off);
                    v1 = dequantize_x4x2_mxfp4_group_hvx(r1 + byte_off, upper, sub_blk, vlut_cvt, r1_e8);
                } else {
                    v1 = Q6_V_vzero();
                }

                Q6_vscatter_QRMVwV(q_mask64, (size_t) tile_base, HMX_FP16_TILE_SIZE - 1, v_off, v0);
                v_off = Q6_Vw_vadd_VwVw(v_off, v_scat_step);
                Q6_vscatter_QRMVwV(q_mask64, (size_t) tile_base, HMX_FP16_TILE_SIZE - 1, v_off, v1);
                v_off = Q6_Vw_vadd_VwVw(v_off, v_scat_step);
            }
            (void) *(volatile HVX_Vector *) (tile_base);
        } else {
            // Q8_0
            int blk_idx  = (kt * 32) / QK_Q8_0x4x2;
            int sub_blk  = ((kt * 32) % QK_Q8_0x4x2) / 32;
            int byte_off  = blk_idx * QK_Q8_0x4x2 + sub_blk * 32;
            int scale_off = qrow_size + blk_idx * HMX_X4X2_DBLK_SIZE + sub_blk * (int)sizeof(__fp16);

            HVX_Vector v_off = v_scat_base;  // reset to column 0
            for (int r = 0; r < HMX_FP16_TILE_N_ROWS; r += 2) {
                int row0 = ct * HMX_FP16_TILE_N_COLS + r;
                int row1 = row0 + 1;

                const uint8_t *r0 = vtcm_src + row0 * row_stride;
                const uint8_t *r1 = vtcm_src + row1 * row_stride;

                HVX_Vector v0 = dequantize_x4x2_q8_0_group_hvx(
                    (const int8_t *)(r0 + byte_off), (const __fp16 *)(r0 + scale_off));
                HVX_Vector v1 = (row1 < n_cols)
                    ? dequantize_x4x2_q8_0_group_hvx(
                        (const int8_t *)(r1 + byte_off), (const __fp16 *)(r1 + scale_off))
                    : Q6_V_vzero();

                Q6_vscatter_QRMVwV(q_mask64, (size_t)tile_base, HMX_FP16_TILE_SIZE - 1, v_off, v0);
                v_off = Q6_Vw_vadd_VwVw(v_off, v_scat_step);
                Q6_vscatter_QRMVwV(q_mask64, (size_t)tile_base, HMX_FP16_TILE_SIZE - 1, v_off, v1);
                v_off = Q6_Vw_vadd_VwVw(v_off, v_scat_step);
            }
            (void) *(volatile HVX_Vector *)(tile_base);
        }
        ++t;
    }

    // Drain HVX scatter write buffer: a vmem load on the same HW thread retires
    // all pending scatter entries to VTCM.  Without this, the main thread's HMX
    // reads may see stale data because atomic_fetch_sub (release) only orders
    // regular stores, not the HVX scatter buffer.
    if (start_tile < end_tile) {
        (void) *(volatile HVX_Vector *)(vtcm_dst + (end_tile - 1) * HMX_FP16_TILE_N_ELMS);
    }
}

typedef struct {
    __fp16        *dst;
    const uint8_t *src;
    int            n_cols;
    int            k_block;
    size_t         row_stride;
    int            weight_type;
    int            n_tot_tiles;
    int            n_tiles_per_task;
    int            n_tasks;
} x4x2_dequantize_state_t;

static void dequantize_x4x2_worker_loop(unsigned int n, unsigned int i, void *data) {
    x4x2_dequantize_state_t *state = (x4x2_dequantize_state_t *)data;

    for (unsigned int task_id = i; task_id < (unsigned int)state->n_tasks; task_id += n) {
        int start = task_id * state->n_tiles_per_task;
        int end   = hex_smin(start + state->n_tiles_per_task, state->n_tot_tiles);

        dequantize_x4x2_weight_to_fp16_tiles_task(
            state->dst, state->src, state->n_cols, state->k_block,
            state->row_stride, state->weight_type, start, end);
    }
}

static void dequantize_x4x2_weight_chunk_to_fp16_tiles(
        struct htp_context *ctx, __fp16 *vtcm_dst,
        const void *vtcm_src, int n_cols, int k_block,
        size_t row_stride, int weight_type) {

    assert(n_cols  % HMX_FP16_TILE_N_COLS == 0);
    assert(k_block % HMX_FP16_TILE_N_COLS == 0);

    int n_col_tiles = n_cols / HMX_FP16_TILE_N_COLS;
    int n_k_tiles   = k_block / HMX_FP16_TILE_N_COLS;
    int n_tot_tiles = n_col_tiles * n_k_tiles;

    size_t n_tiles_per_task = hmx_ceil_div(n_tot_tiles, ctx->n_threads);

    x4x2_dequantize_state_t state;
    state.n_tasks          = (n_tot_tiles + n_tiles_per_task - 1) / n_tiles_per_task;
    state.n_tot_tiles      = n_tot_tiles;
    state.n_tiles_per_task = n_tiles_per_task;
    state.dst         = vtcm_dst;
    state.src         = (const uint8_t *)vtcm_src;
    state.n_cols      = n_cols;
    state.k_block     = k_block;
    state.row_stride  = row_stride;
    state.weight_type = weight_type;

    worker_pool_run_func(ctx->worker_pool, dequantize_x4x2_worker_loop, &state, ctx->n_threads);
}

// --- End x4x2 dequantizers ---

// requires external HMX lock
static void core_dot_chunk_fp16(__fp16 *output, const __fp16 *activation, const __fp16 *weight, const __fp16 *scales,
                                int n_row_tiles, int n_col_tiles, int n_dot_tiles) {
    hmx_set_output_scales(scales);

    for (int r = 0; r < n_row_tiles; ++r) {
        for (int c = 0; c < n_col_tiles; ++c) {
            Q6_mxclracc_hf();

            const __fp16 *row_tiles = activation + r * n_dot_tiles * HMX_FP16_TILE_N_ELMS;
            const __fp16 *col_tiles = weight + c * n_dot_tiles * HMX_FP16_TILE_N_ELMS;

            for (int k = 0; k < n_dot_tiles; ++k) {
                int offset = k * HMX_FP16_TILE_N_ELMS;
                hmx_load_tile_pair_fp16(row_tiles + offset, col_tiles + offset);
            }

            __fp16 *out_tile = output + (r * n_col_tiles + c) * HMX_FP16_TILE_N_ELMS;
            hmx_consume_accumulator_fp16(out_tile);
        }
    }
}

static void transfer_output_chunk_fp16_to_fp32(float *restrict dst, const __fp16 *restrict vtcm_src, int n_rows, int n_cols, int n) {
    assert(n_cols % HMX_FP16_TILE_N_COLS == 0);
    const int n_col_tiles = n_cols / HMX_FP16_TILE_N_COLS;

    const HVX_Vector one = hvx_vec_splat_f16(1.0);

    for (int r = 0; r < n_rows; r += 2) {
        int r0 = r / HMX_FP16_TILE_N_ROWS;
        int r1 = r % HMX_FP16_TILE_N_ROWS;

        #pragma unroll(4)
        for (int c = 0; c < n_cols; c += HMX_FP16_TILE_N_COLS) {
            int c0 = c / HMX_FP16_TILE_N_COLS;

            const __fp16 *tile = vtcm_src + (r0 * n_col_tiles + c0) * HMX_FP16_TILE_N_ELMS;

            HVX_Vector v = ((const HVX_Vector *) tile)[r1 / 2];
            HVX_VectorPair vp = Q6_Wqf32_vmpy_VhfVhf(v, one);

            volatile HVX_Vector *pv_out0 = (volatile HVX_Vector *) (dst + (r * n + c + 0));
            volatile HVX_Vector *pv_out1 = (volatile HVX_Vector *) (dst + (r * n + c + n));  // next row in global memory

            *pv_out0 = Q6_Vsf_equals_Vqf32(Q6_V_lo_W(vp));
            if (r + 1 < n_rows) {
                *pv_out1 = Q6_Vsf_equals_Vqf32(Q6_V_hi_W(vp));
            }
        }
    }
}

typedef struct {
    const __fp16  *vtcm_src;
    float         *dst;
    int            n_tasks;
    int            n_tot_chunks;
    int            n_chunks_per_task;
    int            n_cols;
    int            n;  // DDR row stride (total output columns)
} output_transfer_task_state_t;

static void transfer_output_chunk_worker_fn(unsigned int n, unsigned int i, void *data) {
    output_transfer_task_state_t *st = (output_transfer_task_state_t *) data;

    for (unsigned int task_id = i; task_id < (unsigned int)st->n_tasks; task_id += n) {
        int    chunk_idx  = task_id * st->n_chunks_per_task;
        size_t chunk_size = hex_smin(st->n_tot_chunks - chunk_idx, st->n_chunks_per_task);

        float        *dst      = st->dst      + chunk_idx * st->n;
        const __fp16 *vtcm_src = st->vtcm_src + chunk_idx * st->n_cols;
        transfer_output_chunk_fp16_to_fp32(dst, vtcm_src, chunk_size, st->n_cols, st->n);
    }
}

static void transfer_output_chunk_threaded(struct htp_context *ctx, float *dst, const __fp16 *vtcm_src,
                                              int n_rows, int n_cols, int n) {
    assert(n_cols % HMX_FP16_TILE_N_COLS == 0);

    size_t n_tot_chunks      = n_rows;
    size_t n_chunks_per_task = 32;  // must be multiple of HMX_FP16_TILE_N_ROWS (32)

    output_transfer_task_state_t state;
    state.n_tasks           = (n_tot_chunks + n_chunks_per_task - 1) / n_chunks_per_task;
    state.n_tot_chunks      = n_tot_chunks;
    state.n_chunks_per_task = n_chunks_per_task;
    state.dst               = dst;
    state.vtcm_src          = vtcm_src;
    state.n_cols            = n_cols;
    state.n                 = n;

    worker_pool_run_func(ctx->worker_pool, transfer_output_chunk_worker_fn, &state, ctx->n_threads);
}

static inline int hmx_matmul_batch_r2(const hmx_matmul_w16a32_batched_params_t *params) {
    return params->ne02 > 0 ? params->ne12 / params->ne02 : 1;
}

static inline int hmx_matmul_batch_r3(const hmx_matmul_w16a32_batched_params_t *params) {
    return params->ne03 > 0 ? params->ne13 / params->ne03 : 1;
}

static inline const __fp16 *hmx_matmul_weight_batch_ptr(const hmx_matmul_w16a32_batched_params_t *params,
                                                        int dst_b2, int dst_b3) {
    const int r2 = hmx_matmul_batch_r2(params);
    const int r3 = hmx_matmul_batch_r3(params);
    return (const __fp16 *) ((const uint8_t *) params->permuted_weight +
                             (size_t) (dst_b2 / r2) * params->src0_nb2 +
                             (size_t) (dst_b3 / r3) * params->src0_nb3);
}

static inline const float *hmx_matmul_activation_batch_ptr(const hmx_matmul_w16a32_batched_params_t *params,
                                                           int dst_b2, int dst_b3) {
    return (const float *) ((const uint8_t *) params->activation +
                            (size_t) dst_b2 * params->src1_nb2 +
                            (size_t) dst_b3 * params->src1_nb3);
}

static inline float *hmx_matmul_dst_batch_ptr(const hmx_matmul_w16a32_batched_params_t *params,
                                              int dst_b2, int dst_b3) {
    return (float *) ((uint8_t *) params->dst +
                      (size_t) dst_b2 * params->dst_nb2 +
                      (size_t) dst_b3 * params->dst_nb3);
}

static int hmx_mat_mul_permuted_w16a32_batched_legacy(struct htp_context *ctx,
                                                      const hmx_matmul_w16a32_batched_params_t *params) {
    int ret = 0;
    for (int b3 = 0; b3 < params->ne13 && ret == 0; ++b3) {
        for (int b2 = 0; b2 < params->ne12 && ret == 0; ++b2) {
            ret = hmx_mat_mul_permuted_w16a32(ctx,
                                              hmx_matmul_dst_batch_ptr(params, b2, b3),
                                              hmx_matmul_activation_batch_ptr(params, b2, b3),
                                              hmx_matmul_weight_batch_ptr(params, b2, b3),
                                              params->m, params->k, params->n,
                                              params->act_stride, params->weight_stride);
        }
    }
    return ret;
}

int hmx_mat_mul_permuted_w16a32_batched(struct htp_context *ctx, const hmx_matmul_w16a32_batched_params_t *params) {
    if (!ctx || !params || !params->dst || !params->activation || !params->permuted_weight) { return -1; }
    if (!params->m || !params->k || !params->n) { return -1; }
    if (params->act_stride < params->k || params->weight_stride < params->k || params->dst_stride < params->n) { return -1; }
    if (params->ne02 <= 0 || params->ne03 <= 0 || params->ne12 <= 0 || params->ne13 <= 0) { return -1; }
    if (params->ne12 % params->ne02 != 0 || params->ne13 % params->ne03 != 0) { return -1; }
    if (params->k % 32 != 0 || params->n % 32 != 0) { return -1; }

    if (!hex_is_aligned(params->dst, VLEN) ||
        !hex_is_aligned(params->activation, VLEN) ||
        !hex_is_aligned(params->permuted_weight, VLEN)) {
        return -1;
    }

    const int group_size = hmx_matmul_batch_r2(params);

    if (group_size <= 1) {
        FARF(MEDIUM, "%s: no dim2 GQA reuse (group=%d), using legacy batched loop", __func__, group_size);
        return hmx_mat_mul_permuted_w16a32_batched_legacy(ctx, params);
    }

    // Grouped path: reuse interleaved weight across all q_heads sharing a
    // kv_head.  Each q_head gets its own activation buffer in VTCM (so
    // activation is loaded once per m_chunk and reused across all n_chunks),
    // and each q_head is computed individually to avoid tile-major packing
    // issues.  m_chunk_n_rows is always a multiple of 32 (from
    // hmx_compute_chunks), so per-head tile arrays don't overlap.
    const size_t vtcm_budget  = ctx->vtcm_scratch_size;
    const size_t vec_dot_size = params->k * sizeof(__fp16);

    // When the activation has a large stride (e.g. permuted Q tensor with
    // act_stride >> k), HVX vector loads from strided DDR thrash L2 cache.
    // Allocate an F32 scratch buffer in VTCM and use 2D DMA to gather
    // strided rows into a contiguous block before the F32->F16 conversion.
    const bool use_dma_activation = (params->act_stride > params->k);
    const size_t f32_scratch_per_m = use_dma_activation ? (size_t) params->k * sizeof(float) : 0;

    size_t m_chunk_n_rows = 0, n_chunk_n_cols = 0, vtcm_used = 0;
    if (hmx_compute_chunks(vtcm_budget, /*overhead=*/256,
                             /*per_n=*/3 * vec_dot_size,
                             /*per_m=*/group_size * vec_dot_size + f32_scratch_per_m,
                             /*per_mn=*/sizeof(__fp16),
                             params->m, params->n,
                             &m_chunk_n_rows, &n_chunk_n_cols, &vtcm_used) != 0) {
        FARF(HIGH, "%s: grouped path does not fit VTCM, falling back to legacy batched loop", __func__);
        return hmx_mat_mul_permuted_w16a32_batched_legacy(ctx, params);
    }

    const size_t act_head_stride      = m_chunk_n_rows * (size_t) params->k;  // fp16 elements between heads
    const size_t weight_area_size     = hex_align_up(n_chunk_n_cols * vec_dot_size, HMX_FP16_TILE_SIZE);
    const size_t activation_area_size = hex_align_up(group_size * m_chunk_n_rows * vec_dot_size, HMX_FP16_TILE_SIZE);
    const size_t output_area_size     = hex_align_up(m_chunk_n_rows * n_chunk_n_cols * sizeof(__fp16), HMX_FP16_TILE_SIZE);
    const size_t scratch_area_size    = hex_align_up(n_chunk_n_cols * vec_dot_size, HMX_FP16_TILE_SIZE);
    const size_t f32_scratch_size     = use_dma_activation
        ? hex_align_up(m_chunk_n_rows * (size_t) params->k * sizeof(float), HMX_FP16_TILE_SIZE) : 0;

    uint8_t *vtcm_ptr        = (uint8_t *) ctx->vtcm_base;
    __fp16  *vtcm_weight     = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, weight_area_size);
    __fp16  *vtcm_activation = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, activation_area_size);
    __fp16  *vtcm_output     = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, output_area_size);
    void    *vtcm_scratch0   = vtcm_seq_alloc(&vtcm_ptr, scratch_area_size);
    void    *vtcm_scratch1   = vtcm_seq_alloc(&vtcm_ptr, scratch_area_size);
    __fp16  *vtcm_scales     = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, 256);
    float   *vtcm_f32_act    = use_dma_activation ? (float *) vtcm_seq_alloc(&vtcm_ptr, f32_scratch_size) : NULL;

    if ((size_t) (vtcm_ptr - (uint8_t *) ctx->vtcm_base) > vtcm_budget) {
        FARF(HIGH, "%s: grouped layout overflowed VTCM, falling back to legacy batched loop", __func__);
        return hmx_mat_mul_permuted_w16a32_batched_legacy(ctx, params);
    }

    hmx_init_column_scales(vtcm_scales, Q6_V_vsplat_R(0x3c00));  // fp16: 1.0

    FARF(MEDIUM, "%s: grouped path m=%d k=%d n=%d group=%d streams=%d mc=%zu nc=%zu vtcm=%zu/%zu",
            __func__, params->m, params->k, params->n, group_size, params->ne13,
            m_chunk_n_rows, n_chunk_n_cols,
            (size_t) (vtcm_ptr - (uint8_t *) ctx->vtcm_base), vtcm_budget);

    TIMER_DEFINE(activation_load);
    TIMER_DEFINE(weight_load);
    TIMER_DEFINE(hmx_core);
    TIMER_DEFINE(output_store);
    TIMER_DEFINE(total);

    TIMER_START(total);

    const size_t fp16_row_bytes   = (size_t) params->k * sizeof(__fp16);
    const size_t weight_row_bytes = (size_t) params->weight_stride * sizeof(__fp16);

    for (int b3 = 0; b3 < params->ne13; ++b3) {
        for (int b2_base = 0; b2_base < params->ne12; b2_base += group_size) {
            const __fp16 *weight_group = hmx_matmul_weight_batch_ptr(params, b2_base, b3);

            for (size_t mr = 0; mr < (size_t) params->m; mr += m_chunk_n_rows) {
                const size_t n_rows = hex_smin((size_t) params->m - mr, m_chunk_n_rows);

                // Pre-load activations for all heads in the group (once per m_chunk).
                // When the source is strided (permuted Q), use 2D DMA to gather
                // contiguous rows into a VTCM scratch buffer first, then HVX
                // converts from the contiguous VTCM buffer.  This avoids L2 cache
                // thrashing from HVX loads at large strides.
                TIMER_START(activation_load);
                for (int g = 0; g < group_size; ++g) {
                    const float *activation_chunk = hmx_matmul_activation_batch_ptr(params, b2_base + g, b3) + mr * params->act_stride;
                    __fp16 *vtcm_act_g = vtcm_activation + (size_t) g * act_head_stride;
                    if (use_dma_activation) {
                        const size_t row_bytes    = (size_t) params->k * sizeof(float);
                        const size_t stride_bytes = (size_t) params->act_stride * sizeof(float);
                        dma_queue_push(ctx->dma[0],
                                          dma_make_ptr(vtcm_f32_act, activation_chunk),
                                          row_bytes, stride_bytes, row_bytes, n_rows);
                        dma_queue_pop(ctx->dma[0]);
                        transfer_activation_chunk_threaded(ctx, vtcm_act_g,
                                                              vtcm_f32_act, (int) n_rows,
                                                              params->k, params->k);
                    } else {
                        transfer_activation_chunk_threaded(ctx, vtcm_act_g,
                                                              activation_chunk, (int) n_rows,
                                                              params->k, params->act_stride);
                    }
                }
                TIMER_STOP(activation_load);

                void *buf_curr = vtcm_scratch0;
                void *buf_next = vtcm_scratch1;

                {
                    const size_t n_cols_first = hex_smin((size_t) params->n, n_chunk_n_cols);
                    dma_queue_push(ctx->dma[0], dma_make_ptr(buf_curr, weight_group),
                                      fp16_row_bytes, weight_row_bytes, fp16_row_bytes, n_cols_first);
                }

                HAP_compute_res_hmx_lock(ctx->vtcm_rctx);

                for (size_t nc = 0; nc < (size_t) params->n; nc += n_chunk_n_cols) {
                    const size_t n_cols = hex_smin((size_t) params->n - nc, n_chunk_n_cols);

                    TIMER_START(weight_load);
                    {
                        dma_queue_pop(ctx->dma[0]);

                        const size_t nc_next = nc + n_chunk_n_cols;
                        if (nc_next < (size_t) params->n) {
                            const size_t n_cols_next = hex_smin((size_t) params->n - nc_next, n_chunk_n_cols);
                            const __fp16 *next_weight_chunk = weight_group + nc_next * params->weight_stride;

                            dma_queue_push(ctx->dma[0], dma_make_ptr(buf_next, next_weight_chunk),
                                              fp16_row_bytes, weight_row_bytes, fp16_row_bytes, n_cols_next);
                        }

                        interleave_fp16_weight_chunk_to_tiles(vtcm_weight, (const __fp16 *) buf_curr, n_cols, params->k);
                        swap_ptr(&buf_curr, &buf_next);
                    }
                    TIMER_STOP(weight_load);

                    // Reuse the interleaved weight for every q_head in this GQA group
                    for (int g = 0; g < group_size; ++g) {
                        TIMER_START(hmx_core);
                        {
                            const __fp16 *vtcm_act_g = vtcm_activation + (size_t) g * act_head_stride;
                            const int n_row_tiles = hmx_ceil_div((int) n_rows, HMX_FP16_TILE_N_ROWS);
                            const int n_col_tiles = hmx_ceil_div((int) n_cols, HMX_FP16_TILE_N_COLS);
                            core_dot_chunk_fp16(vtcm_output, vtcm_act_g, vtcm_weight, vtcm_scales,
                                                n_row_tiles, n_col_tiles, params->k / 32);
                        }
                        TIMER_STOP(hmx_core);

                        TIMER_START(output_store);
                        {
                            float *output = hmx_matmul_dst_batch_ptr(params, b2_base + g, b3) + mr * params->dst_stride + nc;
                            transfer_output_chunk_threaded(ctx, output, vtcm_output, (int) n_rows, (int) n_cols, params->dst_stride);
                        }
                        TIMER_STOP(output_store);
                    }
                }

                HAP_compute_res_hmx_unlock(ctx->vtcm_rctx);
            }
        }
    }

    TIMER_STOP(total);

#if defined(ENABLE_PROFILE_TIMERS)
    FARF(HIGH, "%s: %lld us, m=%d k=%d n=%d group=%d", __func__, TIMER_US(total),
         params->m, params->k, params->n, group_size);
    FARF(HIGH, "  activation_load: %lld us, weight_load: %lld us, hmx_core: %lld us, output_store: %lld us",
         TIMER_US(activation_load), TIMER_US(weight_load), TIMER_US(hmx_core), TIMER_US(output_store));
#endif

  return 0;
}

int hmx_mat_mul_permuted_w16a32(struct htp_context *ctx, float *restrict dst, const float *restrict activation,
                                const __fp16 *restrict permuted_weight, int m, int k, int n,
                                int act_stride, int weight_stride) {
    if (!dst || !activation || !permuted_weight || !m || !n || !k) { return -1; }
    if (act_stride < k || weight_stride < k) { return -1; }
    if (k % 32 != 0 || n % 32 != 0) { return -1; }

    if (!hex_is_aligned(dst, VLEN) || !hex_is_aligned(activation, VLEN) || !hex_is_aligned(permuted_weight, VLEN)) {
      return -1;
    }

    // --- Dynamic VTCM layout ---
    const size_t vtcm_budget  = ctx->vtcm_scratch_size;
    const size_t vec_dot_size = k * sizeof(__fp16);

    // DMA-based activation gather for strided tensors (see batched path comment).
    const bool use_dma_activation = (act_stride > k);
    const size_t f32_scratch_per_m = use_dma_activation ? (size_t) k * sizeof(float) : 0;

    size_t m_chunk_n_rows = 0, n_chunk_n_cols = 0, vtcm_used = 0;
    if (hmx_compute_chunks(vtcm_budget,
                              /*overhead=*/ 256,
                              /*per_n=*/    3 * vec_dot_size,  // W + S0 + S1
                              /*per_m=*/    vec_dot_size + f32_scratch_per_m,  // A + optional F32 scratch
                              /*per_mn=*/   sizeof(__fp16),     // O
                              m, n,
                              &m_chunk_n_rows, &n_chunk_n_cols, &vtcm_used) != 0) {
        FARF(HIGH, "%s: VTCM too small (m=%d k=%d n=%d budget=%zu)", __func__, m, k, n, vtcm_budget);
        return -1;
    }

    const size_t weight_area_size     = hex_align_up(n_chunk_n_cols * vec_dot_size, HMX_FP16_TILE_SIZE);
    const size_t activation_area_size = hex_align_up(m_chunk_n_rows * vec_dot_size, HMX_FP16_TILE_SIZE);
    const size_t output_area_size     = hex_align_up(m_chunk_n_rows * n_chunk_n_cols * sizeof(__fp16), HMX_FP16_TILE_SIZE);
    const size_t scratch_area_size    = hex_align_up(n_chunk_n_cols * vec_dot_size, HMX_FP16_TILE_SIZE);
    const size_t f32_scratch_size     = use_dma_activation
        ? hex_align_up(m_chunk_n_rows * (size_t) k * sizeof(float), HMX_FP16_TILE_SIZE) : 0;

    // VTCM layout: weight | activation | output | scratch0 | scratch1 | scales | [f32_scratch]
    uint8_t *vtcm_ptr        = (uint8_t *) ctx->vtcm_base;
    __fp16  *vtcm_weight     = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, weight_area_size);
    __fp16  *vtcm_activation = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, activation_area_size);
    __fp16  *vtcm_output     = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, output_area_size);
    void    *vtcm_scratch0   = vtcm_seq_alloc(&vtcm_ptr, scratch_area_size);
    void    *vtcm_scratch1   = vtcm_seq_alloc(&vtcm_ptr, scratch_area_size);
    __fp16  *vtcm_scales     = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, 256);
    float   *vtcm_f32_act    = use_dma_activation ? (float *) vtcm_seq_alloc(&vtcm_ptr, f32_scratch_size) : NULL;
    if ((size_t)(vtcm_ptr - (uint8_t *)ctx->vtcm_base) > vtcm_budget) {
        FARF(ERROR, "%s: vtcm overflow: used=%zu limit=%zu", __func__,
             (size_t)(vtcm_ptr - (uint8_t *)ctx->vtcm_base), vtcm_budget);
        return -1;
    }

    hmx_init_column_scales(vtcm_scales, Q6_V_vsplat_R(0x3c00));  // fp16: 1.0

    FARF(MEDIUM, "%s: m=%d k=%d n=%d mc=%zu nc=%zu vtcm=%zu/%zu",
         __func__, m, k, n, m_chunk_n_rows, n_chunk_n_cols,
         (size_t)(vtcm_ptr - (uint8_t *)ctx->vtcm_base), vtcm_budget);

    TIMER_DEFINE(activation_load);
    TIMER_DEFINE(weight_load);
    TIMER_DEFINE(hmx_core);
    TIMER_DEFINE(output_store);

    TIMER_DEFINE(total);
    TIMER_START(total);

    HAP_compute_res_hmx_lock(ctx->vtcm_rctx);

    for (size_t mr = 0; mr < m; mr += m_chunk_n_rows) {
        // transfer activation matrix chunk into VTCM
        size_t n_rows = hex_smin(m - mr, m_chunk_n_rows);

        TIMER_START(activation_load);
        {
            const float *activation_chunk = activation + mr * act_stride;
            if (use_dma_activation) {
                const size_t row_bytes    = (size_t) k * sizeof(float);
                const size_t stride_bytes = (size_t) act_stride * sizeof(float);
                dma_queue_push(ctx->dma[0],
                                  dma_make_ptr(vtcm_f32_act, activation_chunk),
                                  row_bytes, stride_bytes, row_bytes, n_rows);
                dma_queue_pop(ctx->dma[0]);
                transfer_activation_chunk_threaded(ctx, vtcm_activation,
                                                      vtcm_f32_act, n_rows, k, k);
            } else {
                transfer_activation_chunk_threaded(ctx, vtcm_activation,
                                                    activation_chunk, n_rows, k, act_stride);
            }
        }
        TIMER_STOP(activation_load);

        const size_t fp16_row_bytes    = (size_t) k * sizeof(__fp16);
        const size_t weight_row_bytes  = (size_t) weight_stride * sizeof(__fp16);

        void *buf_curr = vtcm_scratch0;
        void *buf_next = vtcm_scratch1;

        // issue async DMA for the first weight chunk
        // NOTE: use 2D DMA (n_cols rows x fp16_row_bytes) to avoid 16-bit roiwidth overflow.
        // The source rows can be strided (e.g. KV-cache K after ggml_permute).
        {
            const size_t n_cols_first = hex_smin(n, n_chunk_n_cols);

            dma_queue_push(ctx->dma[0], dma_make_ptr(buf_curr, permuted_weight),
                              fp16_row_bytes, weight_row_bytes, fp16_row_bytes, n_cols_first);
        }

        for (size_t nc = 0; nc < n; nc += n_chunk_n_cols) {
            size_t n_cols = hex_smin(n - nc, n_chunk_n_cols);

            TIMER_START(weight_load);
            {
                dma_queue_pop(ctx->dma[0]);  // wait until current weight chunk is ready

                // issue async DMA for the next weight chunk (double buffering)
                const size_t nc_next = nc + n_chunk_n_cols;
                if (nc_next < n) {
                    const size_t n_cols_next       = hex_smin(n - nc_next, n_chunk_n_cols);
                    const __fp16 *next_weight_chunk = permuted_weight + nc_next * weight_stride;

                    dma_queue_push(ctx->dma[0], dma_make_ptr(buf_next, next_weight_chunk),
                                      fp16_row_bytes, weight_row_bytes, fp16_row_bytes, n_cols_next);
                }

                // interleave row-major fp16 from scratch into tile-major in vtcm_weight
                interleave_fp16_weight_chunk_to_tiles(vtcm_weight, (const __fp16 *)buf_curr, n_cols, k);

                swap_ptr(&buf_curr, &buf_next);
            }
            TIMER_STOP(weight_load);

            TIMER_START(hmx_core);
            {
                const int n_row_tiles = hmx_ceil_div(n_rows, HMX_FP16_TILE_N_ROWS);
                const int n_col_tiles = hmx_ceil_div(n_cols, HMX_FP16_TILE_N_COLS);
                core_dot_chunk_fp16(vtcm_output, vtcm_activation, vtcm_weight, vtcm_scales, n_row_tiles, n_col_tiles, k / 32);
            }
            TIMER_STOP(hmx_core);

            TIMER_START(output_store);
            {
                float *output = dst + (mr * n + nc);
                transfer_output_chunk_threaded(ctx, output, vtcm_output, n_rows, n_cols, n);
            }
            TIMER_STOP(output_store);
        }

    }

    HAP_compute_res_hmx_unlock(ctx->vtcm_rctx);

    TIMER_STOP(total);

#if defined(ENABLE_PROFILE_TIMERS)
    FARF(HIGH, "%s: %lld us, m=%d k=%d n=%d", __func__, TIMER_US(total), m, k, n);
    FARF(HIGH, "  activation_load: %lld us, weight_load: %lld us, hmx_core: %lld us, output_store: %lld us",
         TIMER_US(activation_load), TIMER_US(weight_load), TIMER_US(hmx_core), TIMER_US(output_store));
    {
        size_t weight_size = (size_t)k * n * sizeof(__fp16);
        float  bandwidth   = 1e-3f * weight_size / (float)TIMER_US(weight_load);
        FARF(HIGH, "  weight load bandwidth: %.2f GB/s", bandwidth);
    }
#endif

    return 0;
}

int mat_mul_qk_0_d16a32_out_stationary(struct htp_context *ctx, float *restrict out, const float *restrict x, const uint8_t *restrict w, int m,
                                       int k, int n, int w_type);

int hmx_mat_mul_permuted_qk_0_d16a32(struct htp_context *ctx, float *restrict dst, const float *restrict activation,
                                     const uint8_t *restrict permuted_weight, int m, int k, int n,
                                     int weight_type) {
    if (!dst || !activation || !permuted_weight || !m || !n || !k) { return -1; }
    if (k % 32 != 0 || n % 32 != 0) { return -1; }

    if (!hex_is_aligned(dst, VLEN) || !hex_is_aligned(activation, VLEN) || !hex_is_aligned(permuted_weight, VLEN)) {
        return -1;
    }

    // for large m, k (e.g. prefill FFN Down), use out-stationary version
    if (m >= 128 && k > n && n > 1024) {
        FARF(MEDIUM, "hmx_matmul_qk: OUT-STATIONARY path m=%d k=%d n=%d type=%d (K_BLOCK=512, %d K-iters with fp16 intermediate)",
             m, k, n, weight_type, (k + 511) / 512);
        return mat_mul_qk_0_d16a32_out_stationary(ctx, dst, activation, permuted_weight, m, k, n, weight_type);
    }

    size_t row_stride = get_x4x2_row_stride(weight_type, k);
    if (row_stride == 0) {
        return -1;
    }

    FARF(MEDIUM, "hmx_matmul_qk: STANDARD path m=%d k=%d n=%d type=%d", m, k, n, weight_type);

    // --- Dynamic VTCM layout ---
    const size_t vtcm_budget   = ctx->vtcm_scratch_size;
    const size_t vec_dot_size  = k * sizeof(__fp16);
    const bool   use_pipeline  = (m >= 128) && (k <= n);

    // Select cost parameters based on execution path
    size_t per_n_cost, per_mn_cost;
    if (use_pipeline) {
        per_n_cost  = row_stride + 2 * vec_dot_size;  // Q + S0 + S1 (dequant bufs)
        per_mn_cost = 2 * sizeof(__fp16);              // O x 2 (output double buffer)
    } else {
        per_n_cost  = vec_dot_size + 2 * row_stride;   // W + S0 + S1 (x4x2 DMA bufs)
        per_mn_cost = sizeof(__fp16);                   // O x 1
    }

    size_t m_chunk_n_rows = 0, n_chunk_n_cols = 0, vtcm_used = 0;
    if (hmx_compute_chunks(vtcm_budget, /*overhead=*/256,
                              per_n_cost, /*per_m=*/vec_dot_size, per_mn_cost,
                              m, n, &m_chunk_n_rows, &n_chunk_n_cols, &vtcm_used) != 0) {
        FARF(HIGH, "%s: VTCM too small (m=%d k=%d n=%d pipe=%d budget=%zu)",
             __func__, m, k, n, use_pipeline, vtcm_budget);
        return -1;
    }

    // Compute precise buffer sizes per execution path
    const size_t weight_area_size = hex_align_up(
        n_chunk_n_cols * (use_pipeline ? row_stride : vec_dot_size), HMX_FP16_TILE_SIZE);
    const size_t activation_area_size = hex_align_up(m_chunk_n_rows * vec_dot_size, HMX_FP16_TILE_SIZE);
    const size_t output_area_size = hex_align_up(
        m_chunk_n_rows * n_chunk_n_cols * sizeof(__fp16), HMX_FP16_TILE_SIZE);

    size_t scratch0_size, scratch1_size, scratch2_size;
    if (use_pipeline) {
        scratch0_size = hex_align_up(n_chunk_n_cols * vec_dot_size, HMX_FP16_TILE_SIZE);  // dequant buf 0
        scratch1_size = scratch0_size;                                                    // dequant buf 1
        scratch2_size = output_area_size;                                                 // output buf 1
    } else {
        scratch0_size = hex_align_up(n_chunk_n_cols * row_stride, HMX_FP16_TILE_SIZE);    // x4x2 DMA buf 0
        scratch1_size = scratch0_size;                                                    // x4x2 DMA buf 1
        scratch2_size = 0;                                                                // unused
    }

    uint8_t *vtcm_ptr        = (uint8_t *) ctx->vtcm_base;
    __fp16  *vtcm_weight     = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, weight_area_size);
    __fp16  *vtcm_activation = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, activation_area_size);
    __fp16  *vtcm_output     = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, output_area_size);
    void    *vtcm_scratch0   = vtcm_seq_alloc(&vtcm_ptr, scratch0_size);
    void    *vtcm_scratch1   = vtcm_seq_alloc(&vtcm_ptr, scratch1_size);
    void    *vtcm_scratch2   = scratch2_size ? vtcm_seq_alloc(&vtcm_ptr, scratch2_size) : NULL;
    __fp16  *vtcm_scales     = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, 256);
    if ((size_t)(vtcm_ptr - (uint8_t *)ctx->vtcm_base) > vtcm_budget) {
        FARF(ERROR, "%s: vtcm overflow: used=%zu limit=%zu", __func__,
             (size_t)(vtcm_ptr - (uint8_t *)ctx->vtcm_base), vtcm_budget);
        return -1;
    }

    hmx_init_column_scales(vtcm_scales, Q6_V_vsplat_R(0x3c00));  // fp16: 1.0

    FARF(MEDIUM, "%s: m=%d k=%d n=%d wtype=%d pipe=%d mc=%zu nc=%zu vtcm=%zu/%zu",
         __func__, m, k, n, weight_type, use_pipeline,
         m_chunk_n_rows, n_chunk_n_cols,
         (size_t)(vtcm_ptr - (uint8_t *)ctx->vtcm_base), vtcm_budget);

    TIMER_DEFINE(activation_load);
    TIMER_DEFINE(weight_load);
    TIMER_DEFINE(hmx_core);
    TIMER_DEFINE(output_store);

    TIMER_DEFINE(total);
    TIMER_START(total);

    FARF(MEDIUM, "hmx_matmul_qk: %s mc=%zu nc=%zu vtcm=%zu/%zu",
         use_pipeline ? "PIPELINE" : "SEQUENTIAL", m_chunk_n_rows, n_chunk_n_cols,
         (size_t)(vtcm_ptr - (uint8_t *)ctx->vtcm_base), vtcm_budget);

    HAP_compute_res_hmx_lock(ctx->vtcm_rctx);

    if (!use_pipeline) {
        for (size_t mr = 0; mr < m; mr += m_chunk_n_rows) {
            // transfer activation matrix chunk into VTCM
            size_t n_rows = hex_smin(m - mr, m_chunk_n_rows);

            TIMER_START(activation_load);
            {
                const float *activation_chunk = activation + mr * k;
                transfer_activation_chunk_threaded(ctx, vtcm_activation, activation_chunk, n_rows, k, k);
            }
            TIMER_STOP(activation_load);

            void *buf_curr = vtcm_scratch0;
            void *buf_next = vtcm_scratch1;

            // issue async DDR data transfer for the first weight chunk
            // NOTE: use 2D DMA (n_cols rows x row_stride bytes) instead of 1D
            // because UDMA roiwidth is 16-bit and total size can exceed 65535.
            {
                const size_t n_cols_first = hex_smin(n, n_chunk_n_cols);
                dma_queue_push(ctx->dma[0], dma_make_ptr(buf_curr, permuted_weight), row_stride, row_stride, row_stride, n_cols_first);
            }

            for (size_t nc = 0; nc < n; nc += n_chunk_n_cols) {
                size_t n_cols = hex_smin(n - nc, n_chunk_n_cols);

                TIMER_START(weight_load);
                {
                    dma_queue_pop(ctx->dma[0]);  // wait until current weight chunk become ready

                    const size_t nc_next = nc + n_chunk_n_cols;
                    if (nc_next < n) {
                        const size_t n_cols_next = hex_smin(n - nc_next, n_chunk_n_cols);

                        const uint8_t *next_weight_chunk = permuted_weight + nc_next * row_stride;

                        dma_queue_push(ctx->dma[0], dma_make_ptr(buf_next, next_weight_chunk), row_stride, row_stride, row_stride, n_cols_next);
                    }

                    // Dequant + vscatter writes directly to [K, N] transposed tiles.
                    // HMX computes C = A x B, where A=[M,K] activation, B=[K,N] weight.
                    dequantize_x4x2_weight_chunk_to_fp16_tiles(ctx, vtcm_weight, buf_curr, n_cols, k, row_stride, weight_type);

                    swap_ptr(&buf_curr, &buf_next);
                }
                TIMER_STOP(weight_load);

                TIMER_START(hmx_core);
                {
                    const int n_row_tiles = hmx_ceil_div(n_rows, HMX_FP16_TILE_N_ROWS);
                    const int n_col_tiles = hmx_ceil_div(n_cols, HMX_FP16_TILE_N_COLS);
                    core_dot_chunk_fp16(vtcm_output, vtcm_activation, vtcm_weight, vtcm_scales, n_row_tiles, n_col_tiles, k / 32);
                }
                TIMER_STOP(hmx_core);

                TIMER_START(output_store);
                {
                    float *output = dst + (mr * n + nc);
                    transfer_output_chunk_threaded(ctx, output, vtcm_output, n_rows, n_cols, n);
                }
                TIMER_STOP(output_store);
            }
        }
    } else {
        // 4-stage pipeline: DMA load (A), dequantize (B), HMX matmul (C), store (D)
        // stage B and D (dequantize and store) are expected to be on the critical path

        // A --> B: vtcm_qweight, 1 buffer
        // B --> C: vtcm_weight0/vtcm_weight1, 2 buffers
        // C --> D: vtcm_output0/vtcm_output1, 2 buffers

        //
        // LD ||A3|  | B3 ||
        // MM ||    C2    ||
        // ST || D1 |     ||

        int n_chunk_cnt = hmx_ceil_div(n, n_chunk_n_cols);
        for (size_t mr = 0; mr < m; mr += m_chunk_n_rows) {
            const size_t n_rows = hex_smin(m - mr, m_chunk_n_rows);

            void *vtcm_qweight        = vtcm_weight;
            void *vtcm_weight_bufs[2] = { vtcm_scratch0, vtcm_scratch1 };
            void *vtcm_output_bufs[2] = { vtcm_output, vtcm_scratch2 };

            // prologue: A0
            const size_t n_cols_A0 = hex_smin(n - 0 * n_chunk_n_cols, n_chunk_n_cols);
            {
                // Use 2D DMA (n_cols rows x row_stride) to avoid 16-bit roiwidth overflow.
                const uint8_t *qweight_chunk_A0 = permuted_weight;
                dma_queue_push(ctx->dma[0], dma_make_ptr(vtcm_qweight, qweight_chunk_A0), row_stride, row_stride, row_stride, n_cols_A0);
            }

            {
                const float *activation_chunk = activation + mr * k;
                transfer_activation_chunk_threaded(ctx, vtcm_activation, activation_chunk, n_rows, k, k);
            }

            // prologue: B0, A1, C0, B1
            {
                // B0
                dma_queue_pop(ctx->dma[0]);
                dequantize_x4x2_weight_chunk_to_fp16_tiles(ctx, vtcm_weight_bufs[0], vtcm_qweight, n_cols_A0, k, row_stride, weight_type);

                // A1
                const size_t n_cols_A1 = hex_smin(n - 1 * n_chunk_n_cols, n_chunk_n_cols);
                if (1 < n_chunk_cnt) {
                    const uint8_t *qweight_chunk_A1 = permuted_weight + n_chunk_n_cols * row_stride;
                    dma_queue_push(ctx->dma[0], dma_make_ptr(vtcm_qweight, qweight_chunk_A1), row_stride, row_stride, row_stride, n_cols_A1);
                }

                // C0
                core_dot_chunk_fp16((__fp16 *) vtcm_output_bufs[0], (__fp16 *) vtcm_activation, (__fp16 *) vtcm_weight_bufs[0], vtcm_scales,
                         hmx_ceil_div(n_rows, HMX_FP16_TILE_N_ROWS), hmx_ceil_div(n_cols_A0, HMX_FP16_TILE_N_COLS), k / HMX_FP16_TILE_N_ROWS);

                // B1
                if (1 < n_chunk_cnt) {
                    dma_queue_pop(ctx->dma[0]);
                    dequantize_x4x2_weight_chunk_to_fp16_tiles(ctx, vtcm_weight_bufs[1], vtcm_qweight, n_cols_A1, k, row_stride, weight_type);
                }
            }

            // main loop
            for (int i = 0; i < n_chunk_cnt; ++i) {
                const size_t nc    = i * n_chunk_n_cols;
                const size_t nc_p1 = nc + 1 * n_chunk_n_cols;
                const size_t nc_p2 = nc + 2 * n_chunk_n_cols;

                const size_t n_cols    = hex_smin(n - nc, n_chunk_n_cols);
                const size_t n_cols_p1 = hex_smin(n - nc_p1, n_chunk_n_cols);
                const size_t n_cols_p2 = hex_smin(n - nc_p2, n_chunk_n_cols);

                // issue A_{i+2}
                if (i + 2 < n_chunk_cnt) {
                    const uint8_t *qweight_chunk_p2 = permuted_weight + nc_p2 * row_stride;
                    dma_queue_push(ctx->dma[0], dma_make_ptr(vtcm_qweight, qweight_chunk_p2), row_stride, row_stride, row_stride, n_cols_p2);
                }

                // wait for HMX (C_{i}) -- C_{i} is done

                // result of B_{i+1} (input of C_{i+1}) should be ready now

                // issue C_{i+1}
                if (i + 1 < n_chunk_cnt) {
                    core_dot_chunk_fp16((__fp16 *) vtcm_output_bufs[(i + 1) % 2], (__fp16 *) vtcm_activation, (__fp16 *) vtcm_weight_bufs[(i + 1) % 2], vtcm_scales,
                        hmx_ceil_div(n_rows, HMX_FP16_TILE_N_ROWS), hmx_ceil_div(n_cols_p1, HMX_FP16_TILE_N_COLS), k / HMX_FP16_TILE_N_ROWS);
                }

                // compute D_{i}
                float *output_chunk = dst + (mr * n + nc);
                transfer_output_chunk_threaded(ctx, output_chunk, vtcm_output_bufs[i % 2], n_rows, n_cols, n);

                // wait for DMA (A_{i+2}), compute B_{i+2}
                if (i + 2 < n_chunk_cnt) {
                    dma_queue_pop(ctx->dma[0]);
                    dequantize_x4x2_weight_chunk_to_fp16_tiles(ctx, vtcm_weight_bufs[(i + 2) % 2], vtcm_qweight, n_cols_p2, k, row_stride, weight_type);
                }
            }
        }
    }

    HAP_compute_res_hmx_unlock(ctx->vtcm_rctx);

    TIMER_STOP(total);

#if defined(ENABLE_PROFILE_TIMERS)
    FARF(HIGH, "%s: %lld us, m=%d k=%d n=%d pipeline=%d", __func__, TIMER_US(total), m, k, n, use_pipeline);
    if (!use_pipeline) {
        FARF(HIGH, "  activation_load: %lld us, weight_load: %lld us, hmx_core: %lld us, output_store: %lld us",
             TIMER_US(activation_load), TIMER_US(weight_load), TIMER_US(hmx_core), TIMER_US(output_store));
        size_t weight_size = (size_t)n * row_stride;
        float  bandwidth   = 1e-3f * weight_size / (float)TIMER_US(weight_load);
        FARF(HIGH, "  weight load bandwidth: %.2f GB/s", bandwidth);
    }
#endif

    return 0;
}

// C += AB
void core_mma_chunk_fp16(__fp16 *c, const __fp16 *a, const __fp16 *b, const __fp16 *col_scales, const __fp16 *eye_tile,
                         int n_row_tiles, int n_col_tiles, int n_dot_tiles, bool zero_init) {

    hmx_set_output_scales(col_scales);

    for (int i = 0; i < n_row_tiles; ++i) {
        for (int j = 0; j < n_col_tiles; ++j) {
            Q6_mxclracc_hf();

            const __fp16 *row_tiles = a + i * n_dot_tiles * HMX_FP16_TILE_N_ELMS;
            const __fp16 *col_tiles = b + j * n_dot_tiles * HMX_FP16_TILE_N_ELMS;

            __fp16 *accum_tile = c + (i * n_col_tiles + j) * HMX_FP16_TILE_N_ELMS;
            if (!zero_init) {
                hmx_load_tile_pair_fp16(accum_tile, eye_tile);
            }

            for (int k = 0; k < n_dot_tiles; ++k) {
                int offset = k * HMX_FP16_TILE_N_ELMS;
                hmx_load_tile_pair_fp16(row_tiles + offset, col_tiles + offset);
            }

            hmx_consume_accumulator_fp16(accum_tile);
        }
    }
}

static void transfer_activation_chunk_fp32_to_fp16(__fp16 *restrict vtcm_dst, const float *restrict src, int n_rows,
                                           int k_block, int k_stride) {
    for (int r = 0; r < n_rows; r += 2) {
        int r0 = r / HMX_FP16_TILE_N_ROWS;  // tile row index
        int r1 = r % HMX_FP16_TILE_N_ROWS;  // intra-tile row idx

        const bool next_row_valid = (r + 1) < n_rows;

        const HVX_Vector *pv_in0 = (const HVX_Vector *) (src + (r + 0) * k_stride);
        const HVX_Vector *pv_in1 = (const HVX_Vector *) (src + (r + 1) * k_stride);
        for (int c = 0; c < k_block; c += 32) {
            HVX_Vector v0 = *pv_in0++;
            HVX_Vector v1 = next_row_valid ? *pv_in1++ : Q6_V_vzero();

            HVX_Vector v_out = hvx_vec_f32_to_f16_shuff(v0, v1);

            // compute output position
            int c0       = c / HMX_FP16_TILE_N_COLS;  // tile column index
            int tile_idx = r0 * (k_block / HMX_FP16_TILE_N_COLS) + c0;

            HVX_Vector *tile = (HVX_Vector *) (vtcm_dst + tile_idx * HMX_FP16_TILE_N_ELMS);
            tile[r1 / 2]     = v_out;
        }
    }
}

typedef struct {
    __fp16      *dst;
    const float *src;
    int          n_tasks;
    int          n_tot_chunks;
    int          n_chunks_per_task;
    int          k_block;
    int          k_stride;
} activation_transfer_task_state_t;

static void transfer_activation_chunk_worker_fn(unsigned int n, unsigned int i, void *data) {
    activation_transfer_task_state_t *st = (activation_transfer_task_state_t *) data;

    for (unsigned int task_id = i; task_id < (unsigned int)st->n_tasks; task_id += n) {
        // one chunk: one row
        int    chunk_idx  = task_id * st->n_chunks_per_task;
        size_t chunk_size = hex_smin(st->n_tot_chunks - chunk_idx, st->n_chunks_per_task);

        __fp16      *dst = st->dst + chunk_idx * st->k_block;
        const float *src = st->src + chunk_idx * st->k_stride;
        transfer_activation_chunk_fp32_to_fp16(dst, src, chunk_size, st->k_block, st->k_stride);
    }
}

void transfer_activation_chunk_threaded(struct htp_context *ctx, __fp16 *dst, const float *src, int n_rows, int k_block, int k_stride) {
    assert(k_block % HMX_FP16_TILE_N_COLS == 0 && k_stride % HMX_FP16_TILE_N_COLS == 0);
    assert(VLEN == 32 * sizeof(float));

    size_t n_tot_chunks      = n_rows;
    size_t n_chunks_per_task = 32;  // must be multiple of 32 to ensure correct destination address

    activation_transfer_task_state_t state;
    state.n_tasks           = (n_tot_chunks + n_chunks_per_task - 1) / n_chunks_per_task;
    state.n_tot_chunks      = n_tot_chunks;
    state.n_chunks_per_task = n_chunks_per_task;
    state.dst               = dst;
    state.src               = src;
    state.k_block           = k_block;
    state.k_stride          = k_stride;

    worker_pool_run_func(ctx->worker_pool, transfer_activation_chunk_worker_fn, &state, ctx->n_threads);
}

int mat_mul_qk_0_d16a32_out_stationary(struct htp_context *ctx, float *restrict out, const float *restrict x, const uint8_t *restrict w, int m,
                                       int k, int n, int weight_type) {
    // Runtime check -- k >= 16384 exceeds 2D DMA limit
    if (k >= 16384) {
        FARF(HIGH, "%s: k=%d exceeds 2D DMA limit", __func__, k);
        return -1;
    }
    // assume k % 32 == 0 && n % 32 == 0
    const size_t row_stride = get_x4x2_row_stride(weight_type, k);
    if (row_stride == 0) {
        return -1;
    }

    const size_t vtcm_budget = ctx->vtcm_scratch_size;

    const size_t M_BLOCK_SIZE = 512;
    const size_t N_BLOCK_SIZE = 512;
    const size_t K_BLOCK_SIZE = 512;

    // Compute precise buffer sizes
    const size_t sub_row_stride_alloc = get_x4x2_row_stride(weight_type, K_BLOCK_SIZE);
    const size_t weight_size  = hex_align_up(N_BLOCK_SIZE * K_BLOCK_SIZE * sizeof(__fp16), HMX_FP16_TILE_SIZE);
    const size_t act_size     = hex_align_up(M_BLOCK_SIZE * K_BLOCK_SIZE * sizeof(__fp16), HMX_FP16_TILE_SIZE);
    const size_t out_size     = hex_align_up(M_BLOCK_SIZE * N_BLOCK_SIZE * sizeof(__fp16), HMX_FP16_TILE_SIZE);
    const size_t scratch0_sz  = hex_align_up(N_BLOCK_SIZE * sub_row_stride_alloc, HMX_FP16_TILE_SIZE);
    const size_t scratch1_sz  = hex_align_up(M_BLOCK_SIZE * K_BLOCK_SIZE * sizeof(float), HMX_FP16_TILE_SIZE);

    const size_t total_vtcm = weight_size + act_size + out_size + scratch0_sz + scratch1_sz + HMX_FP16_TILE_SIZE + 256;
    if (total_vtcm > vtcm_budget) {
        FARF(HIGH, "%s: VTCM too small: need %zu have %zu (m=%d k=%d n=%d)", __func__, total_vtcm, vtcm_budget, m, k, n);
        return -1;
    }

    uint8_t *vtcm_ptr        = (uint8_t *) ctx->vtcm_base;
    __fp16  *vtcm_weight     = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, weight_size);
    __fp16  *vtcm_activation = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, act_size);
    __fp16  *vtcm_output     = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, out_size);
    uint8_t *vtcm_scratch0   = vtcm_seq_alloc(&vtcm_ptr, scratch0_sz);
    uint8_t *vtcm_scratch1   = vtcm_seq_alloc(&vtcm_ptr, scratch1_sz);
    __fp16  *vtcm_eye_tile   = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, HMX_FP16_TILE_SIZE);
    __fp16  *vtcm_scales     = (__fp16 *) vtcm_seq_alloc(&vtcm_ptr, 256);
    assert((size_t)(vtcm_ptr - (uint8_t *)ctx->vtcm_base) <= vtcm_budget);

    FARF(MEDIUM, "%s: m=%d k=%d n=%d wtype=%d vtcm=%zu/%zu",
         __func__, m, k, n, weight_type,
         (size_t)(vtcm_ptr - (uint8_t *)ctx->vtcm_base), vtcm_budget);

    // initialize eye tile (32x32 identity matrix)
    {
        HVX_Vector v;
        v = Q6_V_vzero();
        v = Q6_Vw_vinsert_VwR(v, 0x3c000000);
        v = Q6_V_vror_VR(v, VLEN - 4);
        v = Q6_Vw_vinsert_VwR(v, 0x00003c00);
        for (int i = 0; i < 16; ++i) {
            ((HVX_Vector *) vtcm_eye_tile)[i] = v;
            v = Q6_V_vror_VR(v, VLEN - 8);
        }
    }
    hmx_init_column_scales(vtcm_scales, Q6_V_vsplat_R(0x3c00));  // fp16: 1.0

    TIMER_DEFINE(fetch);
    TIMER_DEFINE(act_load);
    TIMER_DEFINE(wt_dequant);
    TIMER_DEFINE(core);

    HAP_compute_res_hmx_lock(ctx->vtcm_rctx);

    for (size_t mr = 0; mr < m; mr += M_BLOCK_SIZE) {
        size_t m_blk_sz = hex_smin(m - mr, M_BLOCK_SIZE);
        for (size_t nc = 0; nc < n; nc += N_BLOCK_SIZE) {
            size_t n_blk_sz = hex_smin(n - nc, N_BLOCK_SIZE);

            const int n_row_tiles = hmx_ceil_div(m_blk_sz, HMX_FP16_TILE_N_ROWS);
            const int n_col_tiles = hmx_ceil_div(n_blk_sz, HMX_FP16_TILE_N_COLS);

            for (size_t kk = 0; kk < k; kk += K_BLOCK_SIZE) {
                size_t k_blk_sz = hex_smin(k - kk, K_BLOCK_SIZE);

                TIMER_START(fetch);
                // fetch activation block into VTCM
                {
                    const float *activation_block = x + mr * k + kk;

                    dma_queue_push(ctx->dma[0],
                                     dma_make_ptr(vtcm_scratch1, activation_block),
                                     k_blk_sz * sizeof(float),
                                     k * sizeof(float),
                                     k_blk_sz * sizeof(float),
                                     m_blk_sz);
                }

                // fetch weight block into VTCM (x4x2 sub-block: quants + scales)
                {
                    qweight_fetch_task_state_t s;

                    const int blk_start = kk / QK_Q4_0x4x2;
                    const int nb_sub = (k_blk_sz + QK_Q4_0x4x2 - 1) / QK_Q4_0x4x2;
                    const int    full_qrow      = (weight_type == HTP_TYPE_Q8_0) ? k : (k / 2);
                    const size_t sub_row_stride = get_x4x2_row_stride(weight_type, k_blk_sz);
                    const int    scale_blk_size =
                        (weight_type == HTP_TYPE_MXFP4) ? HMX_X4X2_MXFP4_EBLK_SIZE : HMX_X4X2_DBLK_SIZE;

                    s.dst         = vtcm_scratch0;
                    s.src         = w + nc * row_stride;
                    s.n_rows      = n_blk_sz;
                    s.src_stride  = row_stride;
                    s.dst_stride  = sub_row_stride;
                    s.quant_off =
                        (weight_type == HTP_TYPE_Q8_0) ? (blk_start * QK_Q8_0x4x2) : (blk_start * (QK_Q4_0x4x2 / 2));
                    s.quant_width =
                        (weight_type == HTP_TYPE_Q8_0) ? (nb_sub * QK_Q8_0x4x2) : (nb_sub * (QK_Q4_0x4x2 / 2));
                    s.scale_off   = full_qrow + blk_start * scale_blk_size;
                    s.scale_width = nb_sub * scale_blk_size;

                    // 2D DMA: quants sub-range
                    dma_queue_push(ctx->dma[0], dma_make_ptr(s.dst, s.src + s.quant_off),
                                      s.dst_stride, s.src_stride, s.quant_width, s.n_rows);
                    // 2D DMA: scales sub-range
                    dma_queue_push(ctx->dma[0], dma_make_ptr(s.dst + s.quant_width, s.src + s.scale_off),
                                      s.dst_stride, s.src_stride, s.scale_width, s.n_rows);
                }
                TIMER_STOP(fetch);

                TIMER_START(act_load);
                // load activation block
                {
                    dma_queue_pop(ctx->dma[0]); // wait for act DNA
                    transfer_activation_chunk_threaded(ctx, vtcm_activation, (float *) vtcm_scratch1, m_blk_sz, k_blk_sz, k_blk_sz);
                }
                TIMER_STOP(act_load);

                TIMER_START(wt_dequant);
                // dequantize weight block
                {
                    dma_queue_pop(ctx->dma[0]);
                    dma_queue_pop(ctx->dma[0]);
                    // vtcm_scratch0 is used to store the qweight chunk
                    // worker_pool_run_func already returned, so fetch is done
                    const size_t sub_row_stride = get_x4x2_row_stride(weight_type, k_blk_sz);
                    dequantize_x4x2_weight_chunk_to_fp16_tiles(ctx, vtcm_weight, vtcm_scratch0,
                                                                n_blk_sz, k_blk_sz, sub_row_stride, weight_type);
                }
                TIMER_STOP(wt_dequant);

                // core mma
                TIMER_START(core);
                {
                    core_mma_chunk_fp16(vtcm_output, vtcm_activation, vtcm_weight, vtcm_scales, vtcm_eye_tile, n_row_tiles,
                                        n_col_tiles, k_blk_sz / HMX_FP16_TILE_N_COLS, kk == 0);
                }
                TIMER_STOP(core);
            }

            // store output block
            {
                float *output_block = out + (mr * n + nc);
                transfer_output_chunk_threaded(ctx, output_block, vtcm_output, m_blk_sz, n_blk_sz, n);
            }
        }
    }

    HAP_compute_res_hmx_unlock(ctx->vtcm_rctx);

#if defined(ENABLE_PROFILE_TIMERS)
    FARF(HIGH, "fetch: %lld us, act_load: %lld us, wt_dequant: %lld us, core: %lld us",
         TIMER_US(fetch), TIMER_US(act_load), TIMER_US(wt_dequant), TIMER_US(core));
#endif
    return 0;
}