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Simplify, generalize, share int16_t taps copy function.

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Also prevents compiler loop unrolling in non-critical code, for code size improvement.
This commit is contained in:
Jared Boone 2016-02-23 15:04:20 -08:00
parent 9c11fdf80c
commit a1b9f4aa1b
1 changed files with 16 additions and 14 deletions
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30
firmware/baseband/dsp_decimate.cpp
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@ -177,6 +177,20 @@ static inline uint32_t scale_round_and_pack(
return __PKHBT(saturated_real, saturated_imag, 16);
}
template<typename Tap>
static void taps_copy(
const Tap* const source,
Tap* const target,
const size_t count,
const bool shift_up
) {
const uint32_t negate_pattern = shift_up ? 0b1110 : 0b0100;
for(size_t i=0; i<count; i++) {
const bool negate = (negate_pattern >> (i & 3)) & 1;
target[i] = negate ? -source[i] : source[i];
}
}
// FIRC8xR16x24FS4Decim4 //////////////////////////////////////////////////
void FIRC8xR16x24FS4Decim4::configure(
@ -184,13 +198,7 @@ void FIRC8xR16x24FS4Decim4::configure(
const int32_t scale,
const Shift shift
) {
const int negate_factor = (shift == Shift::Up) ? -1 : 1;
for(size_t i=0; i<taps.size(); i+=4) {
taps_[i+0] = taps[i+0];
taps_[i+1] = taps[i+1] * negate_factor;
taps_[i+2] = -taps[i+2];
taps_[i+3] = taps[i+3] * negate_factor;
}
taps_copy(taps.data(), taps_.data(), taps_.size(), shift == Shift::Up);
output_scale = scale;
z_.fill({});
}
@ -246,13 +254,7 @@ void FIRC8xR16x24FS4Decim8::configure(
const int32_t scale,
const Shift shift
) {
const int negate_factor = (shift == Shift::Up) ? -1 : 1;
for(size_t i=0; i<taps.size(); i+=4) {
taps_[i+0] = taps[i+0];
taps_[i+1] = taps[i+1] * negate_factor;
taps_[i+2] = -taps[i+2];
taps_[i+3] = taps[i+3] * negate_factor;
}
taps_copy(taps.data(), taps_.data(), taps_.size(), shift == Shift::Up);
output_scale = scale;
z_.fill({});
}