mirror of
https://github.com/eried/portapack-mayhem.git
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Unrolled FIR filters for more flexible baseband filtering (using IFIR technique).
This commit is contained in:
Jared Boone
parent
87c9772128
commit
549e5b9ddc
@ -26,6 +26,284 @@
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namespace dsp {
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namespace decimate {
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static inline complex32_t mac_fs4_shift(
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const vec2_s16* const z,
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const vec2_s16* const t,
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const size_t index,
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const complex32_t accum
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) {
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/* Accumulate sample * tap results for samples already in z buffer.
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* Multiply using swap/negation to achieve Fs/4 shift.
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* For iterations where samples are shifting out of z buffer (being discarded).
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* Expect negated tap t[2] to accomodate instruction set limitations.
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*/
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const bool negated_t2 = index & 1;
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const auto q1_i0 = z[index*2 + 0];
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const auto i1_q0 = z[index*2 + 1];
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const auto t1_t0 = t[index];
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const auto real = negated_t2 ? smlsd(q1_i0, t1_t0, accum.real()) : smlad(q1_i0, t1_t0, accum.real());
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const auto imag = negated_t2 ? smlad(i1_q0, t1_t0, accum.imag()) : smlsd(i1_q0, t1_t0, accum.imag());
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return { real, imag };
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}
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static inline complex32_t mac_shift(
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const vec2_s16* const z,
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const vec2_s16* const t,
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const size_t index,
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const complex32_t accum
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) {
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/* Accumulate sample * tap results for samples already in z buffer.
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* For iterations where samples are shifting out of z buffer (being discarded).
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* real += i1 * t1 + i0 * t0
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* imag += q1 * t1 + q0 * t0
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*/
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const auto i1_i0 = z[index*2 + 0];
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const auto q1_q0 = z[index*2 + 1];
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const auto t1_t0 = t[index];
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const auto real = smlad(i1_i0, t1_t0, accum.real());
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const auto imag = smlad(q1_q0, t1_t0, accum.imag());
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return { real, imag };
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}
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static inline complex32_t mac_fs4_shift_and_store(
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vec2_s16* const z,
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const vec2_s16* const t,
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const size_t decimation_factor,
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const size_t index,
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const complex32_t accum
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) {
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/* Accumulate sample * tap results for samples already in z buffer.
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* Place new samples into z buffer.
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* Expect negated tap t[2] to accomodate instruction set limitations.
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*/
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const bool negated_t2 = index & 1;
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const auto q1_i0 = z[decimation_factor + index*2 + 0];
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const auto i1_q0 = z[decimation_factor + index*2 + 1];
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const auto t1_t0 = t[decimation_factor / 2 + index];
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z[index*2 + 0] = q1_i0;
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const auto real = negated_t2 ? smlsd(q1_i0, t1_t0, accum.real()) : smlad(q1_i0, t1_t0, accum.real());
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z[index*2 + 1] = i1_q0;
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const auto imag = negated_t2 ? smlad(i1_q0, t1_t0, accum.imag()) : smlsd(i1_q0, t1_t0, accum.imag());
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return { real, imag };
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}
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static inline complex32_t mac_shift_and_store(
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vec2_s16* const z,
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const vec2_s16* const t,
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const size_t decimation_factor,
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const size_t index,
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const complex32_t accum
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) {
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/* Accumulate sample * tap results for samples already in z buffer.
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* Place new samples into z buffer.
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* Expect negated tap t[2] to accomodate instruction set limitations.
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*/
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const auto i1_i0 = z[decimation_factor + index*2 + 0];
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const auto q1_q0 = z[decimation_factor + index*2 + 1];
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const auto t1_t0 = t[decimation_factor / 2 + index];
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z[index*2 + 0] = i1_i0;
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const auto real = smlad(i1_i0, t1_t0, accum.real());
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z[index*2 + 1] = q1_q0;
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const auto imag = smlad(q1_q0, t1_t0, accum.imag());
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return { real, imag };
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}
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static inline complex32_t mac_fs4_shift_and_store_new_c8_samples(
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vec2_s16* const z,
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const vec2_s16* const t,
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const vec4_s8* const in,
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const size_t decimation_factor,
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const size_t index,
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const size_t length,
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const complex32_t accum
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) {
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/* Accumulate sample * tap results for new samples.
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* Place new samples into z buffer.
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* Expect negated tap t[2] to accomodate instruction set limitations.
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*/
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const bool negated_t2 = index & 1;
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const auto q1_i1_q0_i0 = in[index];
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const auto t1_t0 = t[(length - decimation_factor) / 2 + index];
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const auto i1_q1_i0_q0 = rev16(q1_i1_q0_i0);
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const auto i1_q1_q0_i0 = pkhbt(q1_i1_q0_i0, i1_q1_i0_q0);
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const auto q1_i0 = sxtb16(i1_q1_q0_i0);
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const auto i1_q0 = sxtb16(i1_q1_q0_i0, 8);
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z[length - decimation_factor * 2 + index*2 + 0] = q1_i0;
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const auto real = negated_t2 ? smlsd(q1_i0, t1_t0, accum.real()) : smlad(q1_i0, t1_t0, accum.real());
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z[length - decimation_factor * 2 + index*2 + 1] = i1_q0;
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const auto imag = negated_t2 ? smlad(i1_q0, t1_t0, accum.imag()) : smlsd(i1_q0, t1_t0, accum.imag());
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return { real, imag };
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}
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static inline complex32_t mac_shift_and_store_new_c16_samples(
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vec2_s16* const z,
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const vec2_s16* const t,
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const vec2_s16* const in,
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const size_t decimation_factor,
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const size_t index,
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const size_t length,
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const complex32_t accum
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) {
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/* Accumulate sample * tap results for new samples.
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* Place new samples into z buffer.
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* Expect negated tap t[2] to accomodate instruction set limitations.
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*/
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const auto q0_i0 = in[index*2+0];
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const auto q1_i1 = in[index*2+1];
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const auto i1_i0 = pkhbt(q0_i0, q1_i1, 16);
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const auto q1_q0 = pkhtb(q1_i1, q0_i0, 16);
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const auto t1_t0 = t[(length - decimation_factor) / 2 + index];
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z[length - decimation_factor * 2 + index*2 + 0] = i1_i0;
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const auto real = smlad(i1_i0, t1_t0, accum.real());
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z[length - decimation_factor * 2 + index*2 + 1] = q1_q0;
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const auto imag = smlad(q1_q0, t1_t0, accum.imag());
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return { real, imag };
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}
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static inline uint32_t scale_round_and_pack(
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const complex32_t value,
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const int32_t scale_factor
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) {
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/* Multiply 32-bit components of the complex<int32_t> by a scale factor,
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* into int64_ts, then round to nearest LSB (1 << 32), saturate to 16 bits,
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* and pack into a complex<int16_t>.
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*/
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const auto scaled_real = __SMMULR(value.real(), scale_factor);
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const auto saturated_real = __SSAT(scaled_real, 16);
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const auto scaled_imag = __SMMULR(value.imag(), scale_factor);
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const auto saturated_imag = __SSAT(scaled_imag, 16);
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return __PKHBT(saturated_real, saturated_imag, 16);
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}
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// FIRC8xR16x24FS4Decim8 //////////////////////////////////////////////////
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FIRC8xR16x24FS4Decim8::FIRC8xR16x24FS4Decim8() {
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z_.fill({});
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}
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void FIRC8xR16x24FS4Decim8::configure(
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const std::array<tap_t, taps_count>& taps,
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const int32_t scale,
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const Shift shift
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) {
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const int negate_factor = (shift == Shift::Up) ? -1 : 1;
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for(size_t i=0; i<taps.size(); i+=4) {
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taps_[i+0] = taps[i+0];
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taps_[i+1] = taps[i+1] * negate_factor;
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taps_[i+2] = -taps[i+2];
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taps_[i+3] = taps[i+3] * negate_factor;
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}
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output_scale = scale;
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}
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buffer_c16_t FIRC8xR16x24FS4Decim8::execute(
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buffer_c8_t src,
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buffer_c16_t dst
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) {
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vec2_s16* const z = static_cast<vec2_s16*>(__builtin_assume_aligned(z_.data(), 4));
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const vec2_s16* const t = static_cast<vec2_s16*>(__builtin_assume_aligned(taps_.data(), 4));
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uint32_t* const d = static_cast<uint32_t*>(__builtin_assume_aligned(dst.p, 4));
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const auto k = output_scale;
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const size_t count = src.count / decimation_factor;
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for(size_t i=0; i<count; i++) {
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const vec4_s8* const in = static_cast<const vec4_s8*>(__builtin_assume_aligned(&src.p[i * decimation_factor], 4));
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complex32_t accum;
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// Oldest samples are discarded.
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accum = mac_fs4_shift(z, t, 0, accum);
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accum = mac_fs4_shift(z, t, 1, accum);
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accum = mac_fs4_shift(z, t, 2, accum);
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accum = mac_fs4_shift(z, t, 3, accum);
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// Middle samples are shifted earlier in the "z" delay buffer.
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accum = mac_fs4_shift_and_store(z, t, decimation_factor, 0, accum);
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accum = mac_fs4_shift_and_store(z, t, decimation_factor, 1, accum);
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accum = mac_fs4_shift_and_store(z, t, decimation_factor, 2, accum);
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accum = mac_fs4_shift_and_store(z, t, decimation_factor, 3, accum);
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// Newest samples come from "in" buffer, are copied to "z" delay buffer.
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accum = mac_fs4_shift_and_store_new_c8_samples(z, t, in, decimation_factor, 0, taps_count, accum);
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accum = mac_fs4_shift_and_store_new_c8_samples(z, t, in, decimation_factor, 1, taps_count, accum);
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accum = mac_fs4_shift_and_store_new_c8_samples(z, t, in, decimation_factor, 2, taps_count, accum);
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accum = mac_fs4_shift_and_store_new_c8_samples(z, t, in, decimation_factor, 3, taps_count, accum);
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d[i] = scale_round_and_pack(accum, k);
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}
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return {
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dst.p,
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count,
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src.sampling_rate / decimation_factor
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};
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}
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// FIRC16xR16x32Decim8 ////////////////////////////////////////////////////
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FIRC16xR16x32Decim8::FIRC16xR16x32Decim8() {
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z_.fill({});
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}
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void FIRC16xR16x32Decim8::configure(
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const std::array<tap_t, taps_count>& taps,
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const int32_t scale
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) {
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std::copy(taps.cbegin(), taps.cend(), taps_.begin());
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output_scale = scale;
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}
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buffer_c16_t FIRC16xR16x32Decim8::execute(
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buffer_c16_t src,
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buffer_c16_t dst
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) {
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vec2_s16* const z = static_cast<vec2_s16*>(__builtin_assume_aligned(z_.data(), 4));
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const vec2_s16* const t = static_cast<vec2_s16*>(__builtin_assume_aligned(taps_.data(), 4));
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uint32_t* const d = static_cast<uint32_t*>(__builtin_assume_aligned(dst.p, 4));
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const auto k = output_scale;
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const size_t count = src.count / decimation_factor;
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for(size_t i=0; i<count; i++) {
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const vec2_s16* const in = static_cast<const vec2_s16*>(__builtin_assume_aligned(&src.p[i * decimation_factor], 4));
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complex32_t accum;
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// Oldest samples are discarded.
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accum = mac_shift(z, t, 0, accum);
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accum = mac_shift(z, t, 1, accum);
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accum = mac_shift(z, t, 2, accum);
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accum = mac_shift(z, t, 3, accum);
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// Middle samples are shifted earlier in the "z" delay buffer.
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accum = mac_shift_and_store(z, t, decimation_factor, 0, accum);
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accum = mac_shift_and_store(z, t, decimation_factor, 1, accum);
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accum = mac_shift_and_store(z, t, decimation_factor, 2, accum);
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accum = mac_shift_and_store(z, t, decimation_factor, 3, accum);
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accum = mac_shift_and_store(z, t, decimation_factor, 4, accum);
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accum = mac_shift_and_store(z, t, decimation_factor, 5, accum);
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accum = mac_shift_and_store(z, t, decimation_factor, 6, accum);
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accum = mac_shift_and_store(z, t, decimation_factor, 7, accum);
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// Newest samples come from "in" buffer, are copied to "z" delay buffer.
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accum = mac_shift_and_store_new_c16_samples(z, t, in, decimation_factor, 0, taps_count, accum);
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accum = mac_shift_and_store_new_c16_samples(z, t, in, decimation_factor, 1, taps_count, accum);
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accum = mac_shift_and_store_new_c16_samples(z, t, in, decimation_factor, 2, taps_count, accum);
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accum = mac_shift_and_store_new_c16_samples(z, t, in, decimation_factor, 3, taps_count, accum);
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d[i] = scale_round_and_pack(accum, k);
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}
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return {
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dst.p,
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count,
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src.sampling_rate / decimation_factor
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};
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}
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buffer_c16_t Complex8DecimateBy2CIC3::execute(buffer_c8_t src, buffer_c16_t dst) {
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/* Decimates by two using a non-recursive third-order CIC filter.
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*/
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@ -31,6 +31,8 @@
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#include "dsp_types.hpp"
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#include "simd.hpp"
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namespace dsp {
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namespace decimate {
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@ -90,6 +92,64 @@ private:
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const std::array<int16_t, taps_count>& taps;
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};
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class FIRC8xR16x24FS4Decim8 {
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public:
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static constexpr size_t taps_count = 24;
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static constexpr size_t decimation_factor = 8;
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using sample_t = complex8_t;
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using tap_t = int16_t;
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enum class Shift : bool {
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Down = true,
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Up = false
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};
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FIRC8xR16x24FS4Decim8();
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void configure(
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const std::array<tap_t, taps_count>& taps,
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const int32_t scale,
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const Shift shift = Shift::Down
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);
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buffer_c16_t execute(
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buffer_c8_t src,
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buffer_c16_t dst
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);
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private:
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std::array<vec2_s16, taps_count - decimation_factor> z_;
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std::array<tap_t, taps_count> taps_;
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int32_t output_scale = 0;
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};
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class FIRC16xR16x32Decim8 {
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public:
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static constexpr size_t taps_count = 32;
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static constexpr size_t decimation_factor = 8;
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using sample_t = complex16_t;
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using tap_t = int16_t;
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FIRC16xR16x32Decim8();
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void configure(
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const std::array<tap_t, taps_count>& taps,
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const int32_t scale
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);
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buffer_c16_t execute(
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buffer_c16_t src,
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buffer_c16_t dst
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);
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private:
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std::array<vec2_s16, taps_count - decimation_factor> z_;
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std::array<tap_t, taps_count> taps_;
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int32_t output_scale = 0;
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};
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class FIRAndDecimateComplex {
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public:
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using sample_t = complex16_t;
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