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Optimize Newton-Raphson cuberoot with SSE2/SSE4.1

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Do all colors in parallel using SIMD.

Change-Id: I36cb47888d92c4244b5ea7a91c8d84ac3656c56a
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Allan Sandfeld Jensen 2024-03-14 11:07:44 +01:00
parent 27a3d3ac90
commit f944651e3d
1 changed files with 36 additions and 0 deletions
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36
src/gui/painting/qcolormatrix_p.h
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@ -18,6 +18,7 @@
#include <QtGui/qtguiglobal.h>
#include <QtCore/qpoint.h>
#include <QtCore/private/qglobal_p.h>
#include <QtCore/private/qsimd_p.h>
#include <cmath>
QT_BEGIN_NAMESPACE
@ -74,6 +75,40 @@ public:
constexpr QColorVector ref = D50();
constexpr float eps = 0.008856f;
constexpr float kap = 903.3f;
#if defined(__SSE2__)
const __m128 iref = _mm_setr_ps(1.f / ref.x, 1.f / ref.y, 1.f / ref.z, 0.f);
__m128 v = _mm_loadu_ps(&x);
v = _mm_mul_ps(v, iref);
const __m128 f3 = _mm_set1_ps(3.f);
__m128 est = _mm_add_ps(_mm_set1_ps(0.25f), _mm_mul_ps(v, _mm_set1_ps(0.75f))); // float est = 0.25f + (x * 0.75f);
__m128 estsq = _mm_mul_ps(est, est);
est = _mm_sub_ps(est, _mm_mul_ps(_mm_sub_ps(_mm_mul_ps(estsq, est), v),
_mm_rcp_ps(_mm_mul_ps(estsq, f3)))); // est -= ((est * est * est) - x) / (3.f * (est * est));
estsq = _mm_mul_ps(est, est);
est = _mm_sub_ps(est, _mm_mul_ps(_mm_sub_ps(_mm_mul_ps(estsq, est), v),
_mm_rcp_ps(_mm_mul_ps(estsq, f3)))); // est -= ((est * est * est) - x) / (3.f * (est * est));
estsq = _mm_mul_ps(est, est);
est = _mm_sub_ps(est, _mm_mul_ps(_mm_sub_ps(_mm_mul_ps(estsq, est), v),
_mm_rcp_ps(_mm_mul_ps(estsq, f3)))); // est -= ((est * est * est) - x) / (3.f * (est * est));
estsq = _mm_mul_ps(est, est);
est = _mm_sub_ps(est, _mm_mul_ps(_mm_sub_ps(_mm_mul_ps(estsq, est), v),
_mm_rcp_ps(_mm_mul_ps(estsq, f3)))); // est -= ((est * est * est) - x) / (3.f * (est * est));
__m128 kapmul = _mm_mul_ps(_mm_add_ps(_mm_mul_ps(v, _mm_set1_ps(kap)), _mm_set1_ps(16.f)),
_mm_set1_ps(1.f / 116.f)); // f_ = (kap * f_ + 16.f) * (1.f / 116.f);
__m128 cmpgt = _mm_cmpgt_ps(v, _mm_set1_ps(eps)); // if (f_ > eps)
#if defined(__SSE4_1__)
v = _mm_blendv_ps(kapmul, est, cmpgt); // if (..) f_ =.. else f_ =..
#else
v = _mm_or_ps(_mm_and_ps(cmpgt, est), _mm_andnot_ps(cmpgt, kapmul));
#endif
QColorVector out;
_mm_store_ps(&out.x, v);
const float L = 116.f * out.y - 16.f;
const float a = 500.f * (out.x - out.y);
const float b = 200.f * (out.y - out.z);
#else
float xr = x * (1.f / ref.x);
float yr = y * (1.f / ref.y);
float zr = z * (1.f / ref.z);
@ -95,6 +130,7 @@ public:
const float L = 116.f * fy - 16.f;
const float a = 500.f * (fx - fy);
const float b = 200.f * (fy - fz);
#endif
// We output Lab values that has been scaled to 0.0->1.0 values, see also labToXyz.
return QColorVector(L * (1.f / 100.f), (a + 128.f) * (1.f / 255.f), (b + 128.f) * (1.f / 255.f));
}