diff --git a/src/layer/arm/gemm_arm.cpp b/src/layer/arm/gemm_arm.cpp
index 2d4ff8734f8..f6ea6bc87c8 100644
--- a/src/layer/arm/gemm_arm.cpp
+++ b/src/layer/arm/gemm_arm.cpp
@@ -3785,9 +3785,9 @@ static void get_optimal_tile_mnk(int M, int N, int K, int constant_TILE_M, int c
 
 static int gemm_arm(const Mat& A, const Mat& B, const Mat& C, Mat& top_blob, int broadcast_type_C, int transA, int transB, int output_transpose, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-    const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
-    const int N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+    const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+    const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
+    const int N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -3840,8 +3840,8 @@ static int gemm_arm(const Mat& A, const Mat& B, const Mat& C, Mat& top_blob, int
         const int i = ppi * TILE_M;
 
         // shadowed variable for less openmp task args
-        const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
+        const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
 
         const int max_ii = std::min((M - i), TILE_M);
 
@@ -3899,7 +3899,7 @@ static int gemm_arm(const Mat& A, const Mat& B, const Mat& C, Mat& top_blob, int
 
 static int gemm_AT_arm(const Mat& AT, const Mat& B, const Mat& C, Mat& top_blob, int broadcast_type_C, int M, int K, int transB, int output_transpose, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+    const int N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -3994,7 +3994,7 @@ static int gemm_AT_arm(const Mat& AT, const Mat& B, const Mat& C, Mat& top_blob,
 
 static int gemm_BT_arm(const Mat& A, const Mat& BT, const Mat& C, Mat& top_blob, int broadcast_type_C, int N, int K, int transA, int output_transpose, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
+    const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -4018,8 +4018,8 @@ static int gemm_BT_arm(const Mat& A, const Mat& BT, const Mat& C, Mat& top_blob,
         const int i = ppi * TILE_M;
 
         // shadowed variable for less openmp task args
-        const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
+        const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
 
         const int max_ii = std::min((M - i), TILE_M);
 
@@ -4329,20 +4329,20 @@ int Gemm_arm::forward(const std::vector<Mat>& bottom_blobs, std::vector<Mat>& to
     {
         const Mat& B = bottom_blobs[0];
         M = constantM;
-        N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+        N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
     }
     else if (constantB)
     {
         const Mat& A = bottom_blobs[0];
-        M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
+        M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
         N = constantN;
     }
     else
     {
         const Mat& A = bottom_blobs[0];
         const Mat& B = bottom_blobs[1];
-        M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+        M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
     }
 
     Mat C;
@@ -4502,9 +4502,9 @@ int Gemm_arm::forward(const std::vector<Mat>& bottom_blobs, std::vector<Mat>& to
 #if NCNN_BF16
 static int gemm_arm_bf16s(const Mat& A, const Mat& B, const Mat& C, Mat& top_blob, int broadcast_type_C, int transA, int transB, int output_transpose, float alpha, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-    const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
-    const int N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+    const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+    const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
+    const int N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -4557,8 +4557,8 @@ static int gemm_arm_bf16s(const Mat& A, const Mat& B, const Mat& C, Mat& top_blo
         const int i = ppi * TILE_M;
 
         // shadowed variable for less openmp task args
-        const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
+        const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
 
         const int max_ii = std::min((M - i), TILE_M);
 
@@ -4617,7 +4617,7 @@ static int gemm_arm_bf16s(const Mat& A, const Mat& B, const Mat& C, Mat& top_blo
 
 static int gemm_AT_arm_bf16s(const Mat& AT, const Mat& B, const Mat& C, Mat& top_blob, int broadcast_type_C, int M, int K, int transB, int output_transpose, float alpha, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+    const int N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -4713,7 +4713,7 @@ static int gemm_AT_arm_bf16s(const Mat& AT, const Mat& B, const Mat& C, Mat& top
 
 static int gemm_BT_arm_bf16s(const Mat& A, const Mat& BT, const Mat& C, Mat& top_blob, int broadcast_type_C, int N, int K, int transA, int output_transpose, float alpha, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
+    const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -4737,8 +4737,8 @@ static int gemm_BT_arm_bf16s(const Mat& A, const Mat& BT, const Mat& C, Mat& top
         const int i = ppi * TILE_M;
 
         // shadowed variable for less openmp task args
-        const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
+        const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
 
         const int max_ii = std::min((M - i), TILE_M);
 
@@ -5001,20 +5001,20 @@ int Gemm_arm::forward_bf16s(const std::vector<Mat>& bottom_blobs, std::vector<Ma
     {
         const Mat& B = bottom_blobs[0];
         M = constantM;
-        N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+        N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
     }
     else if (constantB)
     {
         const Mat& A = bottom_blobs[0];
-        M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
+        M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
         N = constantN;
     }
     else
     {
         const Mat& A = bottom_blobs[0];
         const Mat& B = bottom_blobs[1];
-        M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+        M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
     }
 
     Mat C;
diff --git a/src/layer/arm/gemm_arm_asimdhp.cpp b/src/layer/arm/gemm_arm_asimdhp.cpp
index 155658ab077..55bb4b0c145 100644
--- a/src/layer/arm/gemm_arm_asimdhp.cpp
+++ b/src/layer/arm/gemm_arm_asimdhp.cpp
@@ -2344,9 +2344,9 @@ static void get_optimal_tile_mnk_fp16sa(int M, int N, int K, int constant_TILE_M
 
 static int gemm_arm_fp16sa(const Mat& A, const Mat& B, const Mat& C, Mat& top_blob, int broadcast_type_C, int transA, int transB, int output_transpose, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-    const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
-    const int N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+    const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+    const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
+    const int N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -2399,8 +2399,8 @@ static int gemm_arm_fp16sa(const Mat& A, const Mat& B, const Mat& C, Mat& top_bl
         const int i = ppi * TILE_M;
 
         // shadowed variable for less openmp task args
-        const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
+        const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
 
         const int max_ii = std::min((M - i), TILE_M);
 
@@ -2458,7 +2458,7 @@ static int gemm_arm_fp16sa(const Mat& A, const Mat& B, const Mat& C, Mat& top_bl
 
 static int gemm_AT_arm_fp16sa(const Mat& AT, const Mat& B, const Mat& C, Mat& top_blob, int broadcast_type_C, int M, int K, int transB, int output_transpose, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+    const int N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -2553,7 +2553,7 @@ static int gemm_AT_arm_fp16sa(const Mat& AT, const Mat& B, const Mat& C, Mat& to
 
 static int gemm_BT_arm_fp16sa(const Mat& A, const Mat& BT, const Mat& C, Mat& top_blob, int broadcast_type_C, int N, int K, int transA, int output_transpose, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
+    const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -2577,8 +2577,8 @@ static int gemm_BT_arm_fp16sa(const Mat& A, const Mat& BT, const Mat& C, Mat& to
         const int i = ppi * TILE_M;
 
         // shadowed variable for less openmp task args
-        const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
+        const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
 
         const int max_ii = std::min((M - i), TILE_M);
 
@@ -2835,20 +2835,20 @@ int Gemm_arm::forward_fp16sa(const std::vector<Mat>& bottom_blobs, std::vector<M
     {
         const Mat& B = bottom_blobs[0];
         M = constantM;
-        N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+        N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
     }
     else if (constantB)
     {
         const Mat& A = bottom_blobs[0];
-        M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
+        M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
         N = constantN;
     }
     else
     {
         const Mat& A = bottom_blobs[0];
         const Mat& B = bottom_blobs[1];
-        M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+        M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
     }
 
     Mat C;
diff --git a/src/layer/arm/gemm_arm_vfpv4.cpp b/src/layer/arm/gemm_arm_vfpv4.cpp
index 3d29af41860..2c4f8ffef6f 100644
--- a/src/layer/arm/gemm_arm_vfpv4.cpp
+++ b/src/layer/arm/gemm_arm_vfpv4.cpp
@@ -31,9 +31,9 @@ extern void pack_A_tile(const Mat& A, Mat& AT, int i, int max_ii, int k, int max
 
 static int gemm_arm_fp16s(const Mat& A, const Mat& B, const Mat& C, Mat& top_blob, int broadcast_type_C, int transA, int transB, int output_transpose, float alpha, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-    const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
-    const int N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+    const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+    const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
+    const int N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -86,8 +86,8 @@ static int gemm_arm_fp16s(const Mat& A, const Mat& B, const Mat& C, Mat& top_blo
         const int i = ppi * TILE_M;
 
         // shadowed variable for less openmp task args
-        const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
+        const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
 
         const int max_ii = std::min((M - i), TILE_M);
 
@@ -146,7 +146,7 @@ static int gemm_arm_fp16s(const Mat& A, const Mat& B, const Mat& C, Mat& top_blo
 
 static int gemm_AT_arm_fp16s(const Mat& AT, const Mat& B, const Mat& C, Mat& top_blob, int broadcast_type_C, int M, int K, int transB, int output_transpose, float alpha, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+    const int N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -242,7 +242,7 @@ static int gemm_AT_arm_fp16s(const Mat& AT, const Mat& B, const Mat& C, Mat& top
 
 static int gemm_BT_arm_fp16s(const Mat& A, const Mat& BT, const Mat& C, Mat& top_blob, int broadcast_type_C, int N, int K, int transA, int output_transpose, float alpha, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
+    const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -266,8 +266,8 @@ static int gemm_BT_arm_fp16s(const Mat& A, const Mat& BT, const Mat& C, Mat& top
         const int i = ppi * TILE_M;
 
         // shadowed variable for less openmp task args
-        const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
+        const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
 
         const int max_ii = std::min((M - i), TILE_M);
 
@@ -530,20 +530,20 @@ int Gemm_arm::forward_fp16s(const std::vector<Mat>& bottom_blobs, std::vector<Ma
     {
         const Mat& B = bottom_blobs[0];
         M = constantM;
-        N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+        N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
     }
     else if (constantB)
     {
         const Mat& A = bottom_blobs[0];
-        M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
+        M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
         N = constantN;
     }
     else
     {
         const Mat& A = bottom_blobs[0];
         const Mat& B = bottom_blobs[1];
-        M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+        M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
     }
 
     Mat C;
diff --git a/src/layer/vulkan/gemm_vulkan.cpp b/src/layer/vulkan/gemm_vulkan.cpp
index ad768c63dd2..8542a6e58d7 100644
--- a/src/layer/vulkan/gemm_vulkan.cpp
+++ b/src/layer/vulkan/gemm_vulkan.cpp
@@ -171,9 +171,9 @@ int Gemm_vulkan::forward(const std::vector<VkMat>& bottom_blobs, std::vector<VkM
     vkdev->convert_packing(B0, B, 1, cmd, opt);
     vkdev->convert_packing(C0, C, 1, cmd, opt);
 
-    const int M = constantM ? constantM : transA ? A.w : (A.dims == 3 ? A.c : A.h);
-    const int K = constantK ? constantK : transA ? (A.dims == 3 ? A.c : A.h) : A.w;
-    const int N = constantN ? constantN : transB ? (B.dims == 3 ? B.c : B.h) : B.w;
+    const int M = constantM ? constantM : transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+    const int K = constantK ? constantK : transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
+    const int N = constantN ? constantN : transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
 
     int broadcast_type_C;
     if (constantC)
@@ -303,9 +303,9 @@ int Gemm_vulkan::forward(const std::vector<VkImageMat>& bottom_blobs, std::vecto
     vkdev->convert_packing(B0, B, 1, cmd, opt);
     vkdev->convert_packing(C0, C, 1, cmd, opt);
 
-    const int M = constantM ? constantM : transA ? A.w : (A.dims == 3 ? A.c : A.h);
-    const int K = constantK ? constantK : transA ? (A.dims == 3 ? A.c : A.h) : A.w;
-    const int N = constantN ? constantN : transB ? (B.dims == 3 ? B.c : B.h) : B.w;
+    const int M = constantM ? constantM : transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+    const int K = constantK ? constantK : transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
+    const int N = constantN ? constantN : transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
 
     int broadcast_type_C;
     if (constantC)
diff --git a/src/layer/x86/gemm_x86.cpp b/src/layer/x86/gemm_x86.cpp
index 19cd7ebc09a..da1a14e68d2 100644
--- a/src/layer/x86/gemm_x86.cpp
+++ b/src/layer/x86/gemm_x86.cpp
@@ -6843,9 +6843,9 @@ static void get_optimal_tile_mnk(int M, int N, int K, int constant_TILE_M, int c
 
 static int gemm_x86(const Mat& A, const Mat& B, const Mat& C, Mat& top_blob, int broadcast_type_C, int transA, int transB, int output_transpose, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-    const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
-    const int N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+    const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1) : (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+    const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
+    const int N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -6897,9 +6897,9 @@ static int gemm_x86(const Mat& A, const Mat& B, const Mat& C, Mat& top_blob, int
     {
         const int i = ppi * TILE_M;
 
-        // shadowed variable for less openmp task args
-        const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
+        // shadowed variable for less openmp task args   
+        const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1) : (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
 
         const int max_ii = std::min((M - i), TILE_M);
 
@@ -6957,7 +6957,7 @@ static int gemm_x86(const Mat& A, const Mat& B, const Mat& C, Mat& top_blob, int
 
 static int gemm_AT_x86(const Mat& AT, const Mat& B, const Mat& C, Mat& top_blob, int broadcast_type_C, int M, int K, int transB, int output_transpose, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+    const int N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -7052,7 +7052,7 @@ static int gemm_AT_x86(const Mat& AT, const Mat& B, const Mat& C, Mat& top_blob,
 
 static int gemm_BT_x86(const Mat& A, const Mat& BT, const Mat& C, Mat& top_blob, int broadcast_type_C, int N, int K, int transA, int output_transpose, int constant_TILE_M, int constant_TILE_N, int constant_TILE_K, int nT, const Option& opt)
 {
-    const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
+    const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1) : (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
 
     // NCNN_LOGE("M/N/K = %d %d %d", M, N, K);
 
@@ -7076,8 +7076,8 @@ static int gemm_BT_x86(const Mat& A, const Mat& BT, const Mat& C, Mat& top_blob,
         const int i = ppi * TILE_M;
 
         // shadowed variable for less openmp task args
-        const int M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        const int K = transA ? (A.dims == 3 ? A.c : A.h) * A.elempack : A.w;
+        const int M = transA ? A.w * (A.dims == 1 ? A.elempack : 1) : (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        const int K = transA ? (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack) : A.w * (A.dims == 1 ? A.elempack : 1);
 
         const int max_ii = std::min((M - i), TILE_M);
 
@@ -7348,20 +7348,20 @@ int Gemm_x86::forward(const std::vector<Mat>& bottom_blobs, std::vector<Mat>& to
     {
         const Mat& B = bottom_blobs[0];
         M = constantM;
-        N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+        N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
     }
     else if (constantB)
     {
         const Mat& A = bottom_blobs[0];
-        M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
+        M = transA ? A.w * (A.dims == 1 ? A.elempack : 1): (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
         N = constantN;
     }
     else
     {
         const Mat& A = bottom_blobs[0];
         const Mat& B = bottom_blobs[1];
-        M = transA ? A.w : (A.dims == 3 ? A.c : A.h) * A.elempack;
-        N = transB ? (B.dims == 3 ? B.c : B.h) * B.elempack : B.w;
+        M = transA ? A.w * (A.dims == 1 ? A.elempack : 1) : (A.dims == 3 ? A.c : A.h) * (A.dims == 1 ? 1 : A.elempack);
+        N = transB ? (B.dims == 3 ? B.c : B.h) * (B.dims == 1 ? 1 : B.elempack) : B.w * (B.dims == 1 ? B.elempack : 1);
     }
 
     Mat C;