From 8a4bca986c57062e96f1e58281b3eff52a856ee6 Mon Sep 17 00:00:00 2001
From: rekado <rekado@elephly.net>
Date: Tue, 6 Sep 2016 22:13:03 +0200
Subject: Initial commit.

---
 objects/wip/pitch_detect_fft.axo | 179 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 179 insertions(+)
 create mode 100644 objects/wip/pitch_detect_fft.axo

(limited to 'objects/wip')

diff --git a/objects/wip/pitch_detect_fft.axo b/objects/wip/pitch_detect_fft.axo
new file mode 100644
index 0000000..7692628
--- /dev/null
+++ b/objects/wip/pitch_detect_fft.axo
@@ -0,0 +1,179 @@
+<objdefs>
+   <obj.normal id="pitch detect 128" uuid="89eda14ecd003f22288812e9843218f2d020b7ad" sha="e1ec4fbea98f37a5be48b1f7d3522ed1f7fe3229">
+      <sDescription>spectral analyzer display using 128 input points fft</sDescription>
+      <author>Johannes Taelman, Ricardo Wurmus</author>
+      <license>BSD</license>
+      <inlets>
+         <frac32buffer name="in" description="input"/>
+         <bool32 name="hold" description="hold"/>
+      </inlets>
+      <outlets>
+        <int32 name="pitch" description="pitch"/>
+      </outlets>
+      <params/>
+      <attribs/>
+      <code.declaration><![CDATA[
+#define N 128
+int32_t inbuf[N];
+int32_t outbuf[N];
+// must be twice as wide because the result is
+// stored like {real[0], imag[0], real[1], imag[1]...}
+int32_t fftbuf[2*N];
+arm_rfft_instance_q31 rfft;
+arm_cfft_radix4_instance_q31 cfft;
+int32_t state;
+int32_t max_val = 0;
+uint32_t max_a = 0;
+
+/**    
+ * @brief Maximum value of a Q31 vector.    
+ * @param[in]       *pSrc points to the input vector    
+ * @param[in]       blockSize length of the input vector    
+ * @param[out]      *pResult maximum value returned here    
+ * @param[out]      *pIndex index of maximum value returned here    
+ * @return none.    
+ */
+
+void arm_max_q31(
+  q31_t * pSrc,
+  uint32_t blockSize,
+  q31_t * pResult,
+  uint32_t * pIndex)
+{
+#ifndef ARM_MATH_CM0_FAMILY
+
+  /* Run the below code for Cortex-M4 and Cortex-M3 */
+  q31_t maxVal1, maxVal2, out;                   /* Temporary variables to store the output value. */
+  uint32_t blkCnt, outIndex, count;              /* loop counter */
+
+  /* Initialise the count value. */
+  count = 0u;
+  /* Initialise the index value to zero. */
+  outIndex = 0u;
+  /* Load first input value that act as reference value for comparision */
+  out = *pSrc++;
+
+  /* Loop unrolling */
+  blkCnt = (blockSize - 1u) >> 2u;
+
+  /* Run the below code for Cortex-M4 and Cortex-M3 */
+  while(blkCnt > 0u)
+  {
+    /* Initialize maxVal to the next consecutive values one by one */
+    maxVal1 = *pSrc++;
+
+    maxVal2 = *pSrc++;
+
+    /* compare for the maximum value */
+    if(out < maxVal1)
+    {
+      /* Update the maximum value and its index */
+      out = maxVal1;
+      outIndex = count + 1u;
+    }
+
+    maxVal1 = *pSrc++;
+
+    /* compare for the maximum value */
+    if(out < maxVal2)
+    {
+      /* Update the maximum value and its index */
+      out = maxVal2;
+      outIndex = count + 2u;
+    }
+
+    maxVal2 = *pSrc++;
+
+    /* compare for the maximum value */
+    if(out < maxVal1)
+    {
+      /* Update the maximum value and its index */
+      out = maxVal1;
+      outIndex = count + 3u;
+    }
+
+    /* compare for the maximum value */
+    if(out < maxVal2)
+    {
+      /* Update the maximum value and its index */
+      out = maxVal2;
+      outIndex = count + 4u;
+    }
+
+    count += 4u;
+
+    /* Decrement the loop counter */
+    blkCnt--;
+  }
+
+  /* if (blockSize - 1u) is not multiple of 4 */
+  blkCnt = (blockSize - 1u) % 4u;
+
+#else
+
+  /* Run the below code for Cortex-M0 */
+  q31_t maxVal1, out;                            /* Temporary variables to store the output value. */
+  uint32_t blkCnt, outIndex;                     /* loop counter */
+
+  /* Initialise the index value to zero. */
+  outIndex = 0u;
+  /* Load first input value that act as reference value for comparision */
+  out = *pSrc++;
+
+  blkCnt = (blockSize - 1u);
+
+#endif /* #ifndef ARM_MATH_CM0_FAMILY */
+
+  while(blkCnt > 0u)
+  {
+    /* Initialize maxVal to the next consecutive values one by one */
+    maxVal1 = *pSrc++;
+
+    /* compare for the maximum value */
+    if(out < maxVal1)
+    {
+      /* Update the maximum value and it's index */
+      out = maxVal1;
+      outIndex = blockSize - blkCnt;
+    }
+
+    /* Decrement the loop counter */
+    blkCnt--;
+
+  }
+
+  /* Store the maximum value and its index into destination pointers */
+  *pResult = out;
+  *pIndex = outIndex;
+}
+
+]]></code.declaration>
+      <code.init><![CDATA[
+int i;
+for(i=0;i<N;i++) inbuf[i]=0;
+for(i=0;i<N;i++) outbuf[i]=0;
+state = 0;
+arm_rfft_init_q31(&rfft, &cfft, N,0,1);
+]]></code.init>
+      <code.krate><![CDATA[
+if (state<N){
+  // fill buffer
+  int i;
+  for(i=0;i<BUFSIZE;i++) {
+    inbuf[state++] = inlet_in[i];
+  }
+} else {
+  // compute FFT
+  arm_rfft_q31(&rfft, (q31_t *)inbuf, (q31_t *)fftbuf);
+  // compute magnitude
+  arm_cmplx_mag_q31(fftbuf, outbuf, N);
+
+  // second half is conjugates, so we only look at N/2
+  arm_max_q31(outbuf, N/2, &max_val, &max_a);
+
+  outlet_pitch = max_a;
+  state = 0;
+}
+]]></code.krate>
+   </obj.normal>
+</objdefs>
-- 
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