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Add Linear and Sine folds from Vital Synth (#8)
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* Add linear & sine folds

* Add folder strings

* Use template method for sine fold

* Move the enums to end of list; add a comment so next person
knows to do that; clang-format

---------

Co-authored-by: BaconPaul <[email protected]>
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@KB1RD
KB1RD and BaconPaul authored Sep 8, 2024
1 parent cc4b899 commit a0d3fab
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Showing 4 changed files with 126 additions and 49 deletions.
27 changes: 24 additions & 3 deletions include/sst/waveshapers/Effects.h
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Original file line number Diff line number Diff line change
Expand Up @@ -19,20 +19,41 @@ inline __m128 DIGI_SSE2(QuadWaveshaperState *__restrict, __m128 in, __m128 drive
return _mm_mul_ps(drive, _mm_mul_ps(m16inv, _mm_sub_ps(_mm_cvtepi32_ps(a), mofs)));
}

template <bool DO_FOLD = false>
inline __m128 SINUS_SSE2(QuadWaveshaperState *__restrict s, __m128 in, __m128 drive)
{
const __m128 one = _mm_set1_ps(1.f);
const __m128 m256 = _mm_set1_ps(256.f);
const __m128 m512 = _mm_set1_ps(512.f);

// Scale so that -1.0 - 1.0 goes to 256 - 768
// +6 dB gets you the full sine wave
__m128 x = _mm_mul_ps(in, drive);
x = _mm_add_ps(_mm_mul_ps(x, m256), m512);

// Convert to 32 bit ints
__m128i e = _mm_cvtps_epi32(x);
// Calculate the remainder due to truncation. This is used for later interpolation
__m128 a = _mm_sub_ps(x, _mm_cvtepi32_ps(e));
e = _mm_packs_epi32(e, e);
const __m128i UB = _mm_set1_epi16(0x3fe);
e = _mm_max_epi16(_mm_min_epi16(e, UB), _mm_setzero_si128());

// Template arg -- Compiler will optimize this out
if (DO_FOLD)
{
// Now, make sure the fold pattern repeats
// Fortunately, we're dealing with a power-of-two LUT so we can do a modulus by bitwise and
// like so:
e = _mm_and_si128(e, _mm_set1_epi32(0x3ff));
// Now pack into 16 bit ints. Should already be truncated
// If not, whoops, segfault
e = _mm_packs_epi32(e, e);
}
else
{
// Don't repeat; Instead, clip to zero at the boundaries
e = _mm_packs_epi32(e, e);
const __m128i UB = _mm_set1_epi16(0x3fe);
e = _mm_max_epi16(_mm_min_epi16(e, UB), _mm_setzero_si128());
}

#if MAC
// this should be very fast on C2D/C1D (and there are no macs with K8's)
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6 changes: 5 additions & 1 deletion include/sst/waveshapers/QuadWaveshaper_Impl.h
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Expand Up @@ -32,7 +32,7 @@ inline QuadWaveshaperPtr GetQuadWaveshaper(WaveshaperType type)

// effects
case WaveshaperType::wst_sine:
return SINUS_SSE2;
return SINUS_SSE2<false>;
case WaveshaperType::wst_digital:
return DIGI_SSE2;

Expand Down Expand Up @@ -79,6 +79,10 @@ inline QuadWaveshaperPtr GetQuadWaveshaper(WaveshaperType type)
return WAVEFOLDER<dualFoldADAA>;
case WaveshaperType::wst_westfold:
return WAVEFOLDER<westCoastFoldADAA>;
case WaveshaperType::wst_linearfold:
return LINFOLD_SSE2;
case WaveshaperType::wst_sinefold:
return SINUS_SSE2<true>;

// fuzzes
case WaveshaperType::wst_fuzz:
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39 changes: 39 additions & 0 deletions include/sst/waveshapers/Wavefolders.h
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Expand Up @@ -125,6 +125,45 @@ inline __m128 SoftOneFold(QuadWaveshaperState *__restrict, __m128 x, __m128 driv

return _mm_mul_ps(y, _mm_rcp_ps(num));
}

inline __m128 LINFOLD_SSE2(QuadWaveshaperState *__restrict s, __m128 in, __m128 drive)
{
// The following code is heavily derived from Vital's linear fold (GPLv3, compatible with SST)
// I think there might be some optimizations to be done here, but I haven't messed with it yet
// Lots of constants, yikes
const __m128 mfour = _mm_set1_ps(-4.f);
const __m128 two = _mm_set1_ps(2.f);
const __m128 one = _mm_set1_ps(1.f);
const __m128 p75 = _mm_set1_ps(0.75f);
const __m128 p25 = _mm_set1_ps(0.25f);
const __m128 zero = _mm_set1_ps(0.f);

__m128 x = _mm_mul_ps(in, drive);
// Prescale the input value
x = _mm_mul_ps(x, p25);
x = _mm_add_ps(x, p75);

// Now, perform a modulus by 1
__m128i e = _mm_cvtps_epi32(x);
__m128 a = _mm_sub_ps(x, _mm_cvtepi32_ps(e));
a = _mm_add_ps(a, _mm_and_ps(one, _mm_cmplt_ps(a, zero)));

// Finally, scale the output value
a = _mm_mul_ps(a, mfour);
a = _mm_add_ps(a, two);

// Absolute value
uint32_t v = 0x7fffffff; // Trick C++ into initializing a float mask that clears the sign bit
a = _mm_and_ps(a, _mm_set1_ps(*((float *)&v)));

// Now finish up by shifting down a bit...
a = _mm_sub_ps(a, one);

return a;
}

// Sine fold is implemented in SINUS_SSE2 in Effects.h via template args

} // namespace sst::waveshapers

#endif // SST_WAVESHAPERS_WAVEFOLDERS_H
103 changes: 58 additions & 45 deletions include/sst/waveshapers/WaveshaperConfiguration.h
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Expand Up @@ -7,6 +7,8 @@
namespace sst::waveshapers
{

// Since these are streamed in some properties, please only add items to the end
// Grouping and ordering in uis happens via the groupname below not the order here
enum class WaveshaperType
{
wst_none = 0,
Expand Down Expand Up @@ -65,54 +67,63 @@ enum class WaveshaperType

wst_softfold,

wst_linearfold,
wst_sinefold,

n_ws_types,
};

const char wst_names[(int)WaveshaperType::n_ws_types][32] = {"Off",
"Soft",
"Hard",
"Asymmetric",
"Sine",
"Digital",
"Soft Harmonic 2",
"Soft Harmonic 3",
"Soft Harmonic 4",
"Soft Harmonic 5",
"Full Wave",
"Half Wave Positive",
"Half Wave Negative",
"Soft Rectifier",
"Single Fold",
"Double Fold",
"West Coast Fold",
"Additive 1+2",
"Additive 1+3",
"Additive 1+4",
"Additive 1+5",
"Additive 12345",
"Additive Saw 3",
"Additive Square 3",

"Fuzz",
"Fuzz Soft Clip",
"Heavy Fuzz",
"Fuzz Center",
"Fuzz Soft Edge",

"Sin+x",
"Sin 2x + x",
"Sin 3x + x",
"Sin 7x + x",
"Sin 10x + x",
"2 Cycle",
"7 Cycle",
"10 Cycle",
"2 Cycle Bound",
"7 Cycle Bound",
"10 Cycle Bound",
"Medium",
"OJD",
"Soft Single Fold"};
const char wst_names[(int)WaveshaperType::n_ws_types][32] = {
"Off",
"Soft",
"Hard",
"Asymmetric",
"Sine",
"Digital",

"Soft Harmonic 2",
"Soft Harmonic 3",
"Soft Harmonic 4",
"Soft Harmonic 5",
"Full Wave",
"Half Wave Positive",
"Half Wave Negative",
"Soft Rectifier",
"Single Fold",
"Double Fold",
"West Coast Fold",

"Additive 1+2",
"Additive 1+3",
"Additive 1+4",
"Additive 1+5",
"Additive 12345",
"Additive Saw 3",
"Additive Square 3",

"Fuzz",
"Fuzz Soft Clip",
"Heavy Fuzz",
"Fuzz Center",
"Fuzz Soft Edge",

"Sin+x",
"Sin 2x + x",
"Sin 3x + x",
"Sin 7x + x",
"Sin 10x + x",
"2 Cycle",
"7 Cycle",
"10 Cycle",
"2 Cycle Bound",
"7 Cycle Bound",
"10 Cycle Bound",
"Medium",
"OJD",
"Soft Single Fold",
"Linear Fold",
"Sine Fold",
};

inline std::vector<std::pair<int, std::string>> WaveshaperGroupName()
{
Expand Down Expand Up @@ -158,6 +169,8 @@ inline std::vector<std::pair<int, std::string>> WaveshaperGroupName()
p(sst::waveshapers::WaveshaperType::wst_singlefold, "Wavefolder");
p(sst::waveshapers::WaveshaperType::wst_dualfold, "Wavefolder");
p(sst::waveshapers::WaveshaperType::wst_westfold, "Wavefolder");
p(sst::waveshapers::WaveshaperType::wst_linearfold, "Wavefolder");
p(sst::waveshapers::WaveshaperType::wst_sinefold, "Wavefolder");

p(sst::waveshapers::WaveshaperType::wst_fuzz, "Fuzz");
p(sst::waveshapers::WaveshaperType::wst_fuzzheavy, "Fuzz");
Expand Down

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