NEON shortcut for flat colour blending into 16-bit
This is a shortcut for the needs descriptor
00000077:03515104_00000000_00000000. It requires blending a single 32-bit
colour value into a 16-bit framebuffer.
It's used when fading out the screen, eg. when a modal requester pops-up.
The PF JIT produces code for this using 24 instructions/pixel. The NEON
implementation requires 2.1 instructions/pixel. Performance hasn't been
benchmarked, but the improvement is quite visible.
This code has only been tested by inspection of the fading effect described
above, when press+holding a finger on the home screen to pop up the
Shortcuts/Widgets/Folders/Wallpaper requester.
Along with the NEON version, a fallback v5TE implementation is also provided.
This ARM version of col32cb16blend is not fully optimised, but is a reasonable
implementation, and better than the version produced by the JIT. It is here as
a fallback, if NEON is not available.
diff --git a/libpixelflinger/scanline.cpp b/libpixelflinger/scanline.cpp
index f700306..a2f43eb 100644
--- a/libpixelflinger/scanline.cpp
+++ b/libpixelflinger/scanline.cpp
@@ -80,6 +80,7 @@
static void scanline_perspective_single(context_t* c);
static void scanline_t32cb16blend(context_t* c);
static void scanline_t32cb16(context_t* c);
+static void scanline_col32cb16blend(context_t* c);
static void scanline_memcpy(context_t* c);
static void scanline_memset8(context_t* c);
static void scanline_memset16(context_t* c);
@@ -93,6 +94,8 @@
extern "C" void scanline_t32cb16blend_arm(uint16_t*, uint32_t*, size_t);
extern "C" void scanline_t32cb16_arm(uint16_t *dst, uint32_t *src, size_t ct);
+extern "C" void scanline_col32cb16blend_neon(uint16_t *dst, uint32_t *col, size_t ct);
+extern "C" void scanline_col32cb16blend_arm(uint16_t *dst, uint32_t col, size_t ct);
// ----------------------------------------------------------------------------
@@ -111,6 +114,9 @@
{ { { 0x03010104, 0x00000077, { 0x00000A01, 0x00000000 } },
{ 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
"565 fb, 8888 tx", scanline_t32cb16, init_y_noop },
+ { { { 0x03515104, 0x00000077, { 0x00000000, 0x00000000 } },
+ { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0xFFFFFFFF } } },
+ "565 fb, 8888 fixed color", scanline_col32cb16blend, init_y_packed },
{ { { 0x00000000, 0x00000000, { 0x00000000, 0x00000000 } },
{ 0x00000000, 0x00000007, { 0x00000000, 0x00000000 } } },
"(nop) alpha test", scanline_noop, init_y_noop },
@@ -943,6 +949,8 @@
uint8_t f = c->state.buffers.color.format;
c->packed = ggl_pack_color(c, f,
c->shade.r0, c->shade.g0, c->shade.b0, c->shade.a0);
+ c->packed8888 = ggl_pack_color(c, GGL_PIXEL_FORMAT_RGBA_8888,
+ c->shade.r0, c->shade.g0, c->shade.b0, c->shade.a0);
c->iterators.y = y0;
c->step_y = step_y__nop;
// choose the rectangle blitter
@@ -1253,6 +1261,45 @@
// ----------------------------------------------------------------------------
+void scanline_col32cb16blend(context_t* c)
+{
+ int32_t x = c->iterators.xl;
+ size_t ct = c->iterators.xr - x;
+ int32_t y = c->iterators.y;
+ surface_t* cb = &(c->state.buffers.color);
+ union {
+ uint16_t* dst;
+ uint32_t* dst32;
+ };
+ dst = reinterpret_cast<uint16_t*>(cb->data) + (x+(cb->stride*y));
+
+#if ((ANDROID_CODEGEN >= ANDROID_CODEGEN_ASM) && defined(__arm__))
+#if defined(__ARM_HAVE_NEON) && BYTE_ORDER == LITTLE_ENDIAN
+ scanline_col32cb16blend_neon(dst, &(c->packed8888), ct);
+#else // defined(__ARM_HAVE_NEON) && BYTE_ORDER == LITTLE_ENDIAN
+ scanline_col32cb16blend_arm(dst, GGL_RGBA_TO_HOST(c->packed8888), ct);
+#endif // defined(__ARM_HAVE_NEON) && BYTE_ORDER == LITTLE_ENDIAN
+#else
+ uint32_t s = GGL_RGBA_TO_HOST(c->packed8888);
+ int sA = (s>>24);
+ int f = 0x100 - (sA + (sA>>7));
+ while (ct--) {
+ uint16_t d = *dst;
+ int dR = (d>>11)&0x1f;
+ int dG = (d>>5)&0x3f;
+ int dB = (d)&0x1f;
+ int sR = (s >> ( 3))&0x1F;
+ int sG = (s >> ( 8+2))&0x3F;
+ int sB = (s >> (16+3))&0x1F;
+ sR += (f*dR)>>8;
+ sG += (f*dG)>>8;
+ sB += (f*dB)>>8;
+ *dst++ = uint16_t((sR<<11)|(sG<<5)|sB);
+ }
+#endif
+
+}
+
void scanline_t32cb16(context_t* c)
{
int32_t x = c->iterators.xl;