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NN: apply q7 fix from upstream.
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@ -21,7 +21,7 @@
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* Title: arm_softmax_q7.c
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* Description: Q7 softmax function
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*
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* $Date: 17. January 2018
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* $Date: 20. February 2018
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* $Revision: V.1.0.0
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*
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* Target Processor: Cortex-M cores
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@ -64,43 +64,56 @@ void arm_softmax_q7(const q7_t * vec_in, const uint16_t dim_vec, q7_t * p_out)
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{
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q31_t sum;
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int16_t i;
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q15_t min, max;
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max = -257;
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min = 257;
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uint8_t shift;
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q15_t base;
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base = -257;
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/* We first search for the maximum */
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for (i = 0; i < dim_vec; i++)
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{
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if (vec_in[i] > max)
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if (vec_in[i] > base)
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{
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max = vec_in[i];
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}
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if (vec_in[i] < min)
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{
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min = vec_in[i];
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base = vec_in[i];
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}
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}
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/* we ignore really small values
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* anyway, they will be 0 after shrinking
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* to q7_t
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/*
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* So the base is set to max-8, meaning
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* that we ignore really small values.
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* anyway, they will be 0 after shrinking to q7_t.
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*/
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if (max - min > 8)
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{
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min = max - 8;
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}
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base = base - 8;
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sum = 0;
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for (i = 0; i < dim_vec; i++)
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{
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sum += 0x1 << (vec_in[i] - min);
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if (vec_in[i] > base)
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{
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shift = (uint8_t)__USAT(vec_in[i] - base, 5);
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sum += 0x1 << shift;
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}
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}
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/* This is effectively (0x1 << 20) / sum */
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int output_base = 0x100000 / sum;
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/*
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* Final confidence will be output_base >> ( 13 - (vec_in[i] - base) )
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* so 128 (0x1<<7) -> 100% confidence when sum = 0x1 << 8, output_base = 0x1 << 12
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* and vec_in[i]-base = 8
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*/
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for (i = 0; i < dim_vec; i++)
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{
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/* we leave 7-bit dynamic range, so that 128 -> 100% confidence */
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p_out[i] = (q7_t) __SSAT(((0x1 << (vec_in[i] - min + 20)) / sum) >> 13, 8);
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if (vec_in[i] > base)
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{
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/* Here minimum value of 13+base-vec_in[i] will be 5 */
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shift = (uint8_t)__USAT(13+base-vec_in[i], 5);
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p_out[i] = (q7_t) __SSAT((output_base >> shift), 8);
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} else {
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p_out[i] = 0;
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}
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}
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}
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/**
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