Implement the composition mode Plus with Neon.

On the benchmark tst_QPainter::compositionModes(), this patches gives
the following improvements:
-300x300:opaque: 390%
-300x300:!opaque: 1085%

Reviewed-by: Samuel Rødal

1 files changed, 24 insertions, 0 deletions

diff --git a/src/gui/painting/qdrawhelper_p.h b/src/gui/painting/qdrawhelper_p.h
index d04c70d..75f42a0 100644
--- a/src/gui/painting/qdrawhelper_p.h
+++ b/src/gui/painting/qdrawhelper_p.h
@@ -1944,6 +1944,30 @@ const uint qt_bayer_matrix[16][16] = {
     ((((argb >> 24) * alpha) >> 8) << 24) | (argb & 0x00ffffff)
 
 
+#if QT_POINTER_SIZE == 8 // 64-bit versions
+#define AMIX(mask) (qMin(((qint64(s)&mask) + (qint64(d)&mask)), qint64(mask)))
+#define MIX(mask) (qMin(((qint64(s)&mask) + (qint64(d)&mask)), qint64(mask)))
+#else // 32 bits
+// The mask for alpha can overflow over 32 bits
+#define AMIX(mask) quint32(qMin(((qint64(s)&mask) + (qint64(d)&mask)), qint64(mask)))
+#define MIX(mask) (qMin(((quint32(s)&mask) + (quint32(d)&mask)), quint32(mask)))
+#endif
+
+inline int comp_func_Plus_one_pixel_const_alpha(uint d, const uint s, const uint const_alpha, const uint one_minus_const_alpha)
+{
+    const int result = (AMIX(AMASK) | MIX(RMASK) | MIX(GMASK) | MIX(BMASK));
+    return INTERPOLATE_PIXEL_255(result, const_alpha, d, one_minus_const_alpha);
+}
+
+inline int comp_func_Plus_one_pixel(uint d, const uint s)
+{
+    const int result = (AMIX(AMASK) | MIX(RMASK) | MIX(GMASK) | MIX(BMASK));
+    return result;
+}
+
+#undef MIX
+#undef AMIX
+
 // prototypes of all the composition functions
 void QT_FASTCALL comp_func_SourceOver(uint *dest, const uint *src, int length, uint const_alpha);
 void QT_FASTCALL comp_func_DestinationOver(uint *dest, const uint *src, int length, uint const_alpha);