[feat][nmsis] add nmsis component and nn,dsp demo

examples/dsp/HelperFunctions/ref_helper.c

@@ -0,0 +1,80 @@
+#include "ref.h"
+
+float32_t scratchArray[8192 * 2];
+
+riscv_cfft_instance_f32 ref_cfft_sR_f32_len8192 = {8192, 0, 0, 0};
+
+q31_t ref_sat_n(q31_t num, uint32_t bits)
+{
+    int32_t posMax, negMin;
+    uint32_t i;
+
+    posMax = 1;
+    for (i = 0; i < (bits - 1); i++) {
+        posMax = posMax * 2;
+    }
+
+    if (num > 0) {
+        posMax = (posMax - 1);
+
+        if (num > posMax) {
+            num = posMax;
+        }
+    } else {
+        negMin = -posMax;
+
+        if (num < negMin) {
+            num = negMin;
+        }
+    }
+    return (num);
+}
+
+q31_t ref_sat_q31(q63_t num)
+{
+    if (num > (q63_t)INT_MAX) {
+        return INT_MAX;
+    } else if (num < (q63_t)0xffffffff80000000ll) {
+        return INT_MIN;
+    } else {
+        return (q31_t)num;
+    }
+}
+
+q15_t ref_sat_q15(q31_t num)
+{
+    if (num > (q31_t)SHRT_MAX) {
+        return SHRT_MAX;
+    } else if (num < (q31_t)0xffff8000) {
+        return SHRT_MIN;
+    } else {
+        return (q15_t)num;
+    }
+}
+
+q7_t ref_sat_q7(q15_t num)
+{
+    if (num > (q15_t)SCHAR_MAX) {
+        return SCHAR_MAX;
+    } else if (num < (q15_t)0xff80) {
+        return SCHAR_MIN;
+    } else {
+        return (q7_t)num;
+    }
+}
+
+float32_t ref_pow(float32_t a, uint32_t b)
+{
+    uint32_t i;
+    float32_t r = a;
+
+    for (i = 1; i < b; i++) {
+        r *= a;
+    }
+
+    if (b == 0) {
+        return 1;
+    }
+
+    return r;
+}