diff --git a/src/operators/math/gemm.cpp b/src/operators/math/gemm.cpp
index bb91adcc4db412db137fdc12831bad75e069e38c..22a351866dd62d8bd93b3e97970af54180b878b7 100644
--- a/src/operators/math/gemm.cpp
+++ b/src/operators/math/gemm.cpp
@@ -1214,6 +1214,21 @@ void WriteWithAddRelu(int mc, int nc, float *c, float *C, int ldc) {
 // C = A * B, batchnorm(C)
 void WriteWithBn(int mc, int nc, float *c, float *C, int ldc, float *scale,
                  float *bias) {
+  if (nc < 4) {
+    for (int i = 0; i < mc; ++i) {
+      for (int j = 0; j < nc; ++j) {
+        *C = (*c) * (*scale) + (*bias);
+        C++;
+        c++;
+      }
+      C += (ldc - nc);
+      c += (NC - nc);
+      scale++;
+      bias++;
+    }
+    return;
+  }
+
   int volatile nc1 = nc / 16;
   int _nc1 = nc % 16;
   int volatile nc2 = _nc1 / 4;
@@ -1300,6 +1315,24 @@ void WriteWithBn(int mc, int nc, float *c, float *C, int ldc, float *scale,
 // C = A * B, batchnorm(C), relu(C)
 void WriteWithBnRelu(int mc, int nc, float *c, float *C, int ldc, float *scale,
                      float *bias) {
+  if (nc < 4) {
+    for (int i = 0; i < mc; ++i) {
+      for (int j = 0; j < nc; ++j) {
+        *C = (*c) * (*scale) + (*bias);
+        if (*C < 0) {
+          *C = 0;
+        }
+        C++;
+        c++;
+      }
+      C += (ldc - nc);
+      c += (NC - nc);
+      scale++;
+      bias++;
+    }
+    return;
+  }
+
   int nc1 = nc / 16;
   int _nc1 = nc % 16;
   int nc2 = _nc1 / 4;