Function sz_lookup_sve

include/stringzilla/memory.h:1349–1413

}

SZ_PUBLIC void sz_lookup_sve(sz_ptr_t target, sz_size_t length, sz_cptr_t source, char const lut[sz_at_least_(256)]) {

    if (length <= 128) {
        sz_lookup_serial(target, length, source, lut);
        return;
    }

    // SVE vector length in bytes
    sz_size_t vl = svcntb();

    // Load the 256-byte lookup table into 4 SVE vectors
    svuint8_t lut_0_to_63_vec = svld1_u8(svptrue_b8(), (sz_u8_t const *)(lut + 0));
    svuint8_t lut_64_to_127_vec = svld1_u8(svptrue_b8(), (sz_u8_t const *)(lut + 64));
    svuint8_t lut_128_to_191_vec = svld1_u8(svptrue_b8(), (sz_u8_t const *)(lut + 128));
    svuint8_t lut_192_to_255_vec = svld1_u8(svptrue_b8(), (sz_u8_t const *)(lut + 192));

    svuint8_t mask_0x3f = svdup_u8(0x3f);

    sz_size_t i = 0;

    // Main loop: process full vectors
    while (i + vl <= length) {
        svuint8_t source_vec = svld1_u8(svptrue_b8(), (sz_u8_t const *)(source + i));

        // Create predicates based on top 2 bits (which 64-byte range)
        svbool_t pred_0_63 = svcmplt_n_u8(svptrue_b8(), source_vec, 64);
        svbool_t pred_64_127 = svcmpge_n_u8(svcmplt_n_u8(svptrue_b8(), source_vec, 128), source_vec, 64);
        svbool_t pred_128_191 = svcmpge_n_u8(svcmplt_n_u8(svptrue_b8(), source_vec, 192), source_vec, 128);
        svbool_t pred_192_255 = svcmpge_n_u8(svptrue_b8(), source_vec, 192);

        // Mask indices to bottom 6 bits for indexing within each 64-byte table
        svuint8_t idx = svand_u8_x(svptrue_b8(), source_vec, mask_0x3f);

        // Perform lookups and blend results based on predicates
        svuint8_t result = svsel_u8(pred_0_63, svtbl_u8(lut_0_to_63_vec, idx), svdup_u8(0));
        result = svsel_u8(pred_64_127, svtbl_u8(lut_64_to_127_vec, idx), result);
        result = svsel_u8(pred_128_191, svtbl_u8(lut_128_to_191_vec, idx), result);
        result = svsel_u8(pred_192_255, svtbl_u8(lut_192_to_255_vec, idx), result);

        svst1_u8(svptrue_b8(), (sz_u8_t *)target + i, result);
        i += vl;
    }

    // Handle tail: process remaining elements with predicated operations
    if (i < length) {
        svbool_t pred = svwhilelt_b8_u64(i, length);
        svuint8_t source_vec = svld1_u8(pred, (sz_u8_t const *)(source + i));

        // Create predicates for each range (comparison already uses pred as governing predicate)
        svbool_t pred_0_63 = svcmplt_n_u8(pred, source_vec, 64);
        svbool_t pred_64_127 = svcmpge_n_u8(svcmplt_n_u8(pred, source_vec, 128), source_vec, 64);
        svbool_t pred_128_191 = svcmpge_n_u8(svcmplt_n_u8(pred, source_vec, 192), source_vec, 128);
        svbool_t pred_192_255 = svcmpge_n_u8(pred, source_vec, 192);

        // Mask indices to bottom 6 bits
        svuint8_t idx = svand_u8_x(pred, source_vec, mask_0x3f);

        svuint8_t result = svsel_u8(pred_0_63, svtbl_u8(lut_0_to_63_vec, idx), svdup_u8(0));