Add chw 3x3s2p1_scalar kernels.
PiperOrigin-RevId: 275004948
diff --git a/src/f32-dwconv-spchw/3x3s2p1-scalar.c b/src/f32-dwconv-spchw/3x3s2p1-scalar.c
new file mode 100644
index 0000000..b525bf6
--- /dev/null
+++ b/src/f32-dwconv-spchw/3x3s2p1-scalar.c
@@ -0,0 +1,102 @@
+// Copyright 2019 Google LLC
+//
+// This source code is licensed under the BSD-style license found in the
+// LICENSE file in the root directory of this source tree.
+
+#include <assert.h>
+
+#include <xnnpack/dwconv.h>
+#include <xnnpack/math.h>
+
+
+void xnn_f32_dwconv_spchw_ukernel_3x3s2p1__scalar(
+ size_t m,
+ size_t n,
+ const float* input,
+ const float* weights,
+ float* output,
+ size_t input_tuple_stride,
+ size_t output_tuple_stride,
+ size_t input_width_stride,
+ size_t output_width_stride,
+ const union xnn_f32_spchw_params params[restrict static 1])
+{
+ assert(n != 0);
+
+ const size_t input_width_increment = 2 * input_width_stride - (n/2) * 2 * input_tuple_stride;
+ const size_t output_width_increment = output_width_stride - (n/2) * output_tuple_stride;
+
+ const float params_min = params->scalar.min;
+ const float params_max = params->scalar.max;
+
+ // No vertical padding.
+ const float* i0 = input;
+ const float* i1 = (const float*) ((uintptr_t) i0 + input_width_stride);
+ const float* i2 = (const float*) ((uintptr_t) i1 + input_width_stride);
+
+ float* output0 = output;
+
+ const float vw0 = weights[0];
+ const float vw1 = weights[1];
+ const float vw2 = weights[2];
+ const float vw3 = weights[3];
+ const float vw4 = weights[4];
+ const float vw5 = weights[5];
+ const float vw6 = weights[6];
+ const float vw7 = weights[7];
+ const float vw8 = weights[8];
+ const float vw9 = weights[9];
+
+ while (m > 0) {
+ float vi0x0 = 0.0f;
+ float vi1x0 = 0.0f;
+ float vi2x0 = 0.0f;
+
+ size_t k = n;
+ for (; k >= 2; k -= 2) {
+ const float vi0x1 = *i0; i0 = (const float*) ((uintptr_t) i0 + input_tuple_stride);
+ const float vi1x1 = *i1; i1 = (const float*) ((uintptr_t) i1 + input_tuple_stride);
+ const float vi2x1 = *i2; i2 = (const float*) ((uintptr_t) i2 + input_tuple_stride);
+ const float vi0x2 = *i0; i0 = (const float*) ((uintptr_t) i0 + input_tuple_stride);
+ const float vi1x2 = *i1; i1 = (const float*) ((uintptr_t) i1 + input_tuple_stride);
+ const float vi2x2 = *i2; i2 = (const float*) ((uintptr_t) i2 + input_tuple_stride);
+
+ const float vrow0_accum = vw1 * vi0x0 + vw2 * vi0x1 + vw3 * vi0x2;
+ vi0x0 = vi0x2;
+ const float vrow1_accum = vw4 * vi1x0 + vw5 * vi1x1 + vw6 * vi1x2;
+ vi1x0 = vi1x2;
+ const float vrow2_accum = vw7 * vi2x0 + vw8 * vi2x1 + vw9 * vi2x2;
+ vi2x0 = vi2x2;
+
+ float voutput = (vw0 + vrow0_accum) + (vrow1_accum + vrow2_accum);
+
+ voutput = math_max_f32(voutput, params_min);
+ voutput = math_min_f32(voutput, params_max);
+
+ *output0 = voutput; output0 = (float *) ((uintptr_t) output0 + output_tuple_stride);
+ }
+ // Possibly process the last pixel separately to account for right edge.
+ if (k == 1)
+ {
+ const float vi0x1 = i0[0];
+ const float vi1x1 = i1[0];
+ const float vi2x1 = i2[0];
+ const float vrow0_accum = vw1 * vi0x0 + vw2 * vi0x1;
+ const float vrow1_accum = vw4 * vi1x0 + vw5 * vi1x1;
+ const float vrow2_accum = vw7 * vi2x0 + vw8 * vi2x1;
+
+ float voutput = (vw0 + vrow0_accum) + (vrow1_accum + vrow2_accum);
+
+ voutput = math_max_f32(voutput, params_min);
+ voutput = math_min_f32(voutput, params_max);
+
+ *output0 = voutput;
+ }
+
+ i0 = (const float*) ((uintptr_t) i0 + input_width_increment);
+ i1 = (const float*) ((uintptr_t) i1 + input_width_increment);
+ i2 = (const float*) ((uintptr_t) i2 + input_width_increment);
+ output0 = (float*) ((uintptr_t) output0 + output_width_increment);
+ m--;
+ }
+}