add some code

managed_components/espressif__esp-dsp/modules/math/sqrt/float/dsps_sqrt_f32_ansi.c

@@ -0,0 +1,56 @@
+// Copyright 2018-2019 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "dsps_sqrt.h"
+#include <math.h>
+
+
+inline float dsps_sqrtf_f32_ansi(float f)
+{
+    int result;
+    int *f_ptr = (int *)&f;
+    result = 0x1fbb4000 + (*f_ptr >> 1);
+    const int *p = &result;
+    float *f_result = (float *)p;
+    return *f_result;
+}
+
+esp_err_t dsps_sqrt_f32_ansi(const float *input, float *output, int len)
+{
+    if (NULL == input) {
+        return ESP_ERR_DSP_PARAM_OUTOFRANGE;
+    }
+    if (NULL == output) {
+        return ESP_ERR_DSP_PARAM_OUTOFRANGE;
+    }
+
+    for (int i = 0 ; i < len ; i++) {
+        output[i] = dsps_sqrtf_f32_ansi(input[i]);
+    }
+    return ESP_OK;
+}
+
+float dsps_inverted_sqrtf_f32_ansi(float data )
+{
+    const float x2 = data * 0.5F;
+    const float threehalfs = 1.5F;
+
+    union {
+        float f;
+        uint32_t i;
+    } conv = {data}; // member 'f' set to value of 'data'.
+    conv.i  = 0x5f3759df - ( conv.i >> 1 );
+    conv.f  *= ( threehalfs - ( x2 * conv.f * conv.f ) );
+    return conv.f;
+}