sycl : support nvfp4 type in mul_mat (#21227)

ggml/src/ggml-sycl/dequantize.hpp

@@ -838,4 +838,36 @@ static void dequantize_block_mxfp4(const void * __restrict__ vx, dst_t * __restr
     }
 }
 
+
+template <typename dst_t>
+static void dequantize_block_nvfp4(
+        const void * __restrict__ vx,
+        dst_t * __restrict__ yy,
+        const int64_t ne) {
+    auto          item_ct1 = sycl::ext::oneapi::this_work_item::get_nd_item<3>();
+    const int64_t i        = item_ct1.get_group(2);
+    const int     tid      = item_ct1.get_local_id(2);
+
+    const int64_t base = i * QK_NVFP4;
+    if (base >= ne) {
+        return;
+    }
+
+    const block_nvfp4 * x = (const block_nvfp4 *) vx;
+    const block_nvfp4 & xb = x[i];
+
+    const int sub = tid / (QK_NVFP4_SUB / 2);
+    const int j = tid % (QK_NVFP4_SUB / 2);
+
+    const float d = ggml_sycl_ue4m3_to_fp32(xb.d[sub]);
+    const uint8_t q = xb.qs[sub * (QK_NVFP4_SUB / 2) + j];
+
+    const int64_t y0 = base + sub * QK_NVFP4_SUB + j;
+    const int64_t y1 = y0 + QK_NVFP4_SUB / 2;
+
+    yy[y0] = ggml_sycl_cast<dst_t>(d * kvalues_mxfp4[q & 0x0F]);
+    yy[y1] = ggml_sycl_cast<dst_t>(d * kvalues_mxfp4[q >> 4]);
+}
+
+
 #endif // GGML_SYCL_DEQUANTIZE_HPP