tequilaOS/platform_system_core
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

NEON shortcut for flat colour blending into 16-bit

Browse source 
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.
This commit is contained in:
Martyn Capewell 2009-12-07 15:00:19 +00:00 committed by Dave Butcher
parent 303254eb67
commit f9e8ab03bd
4 changed files with 284 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
libpixelflinger/Android.mk
View file

@ -40,7 +40,13 @@ PIXELFLINGER_SRC_FILES:= \
buffer.cpp
ifeq ($(TARGET_ARCH),arm)
ifeq ($(TARGET_ARCH_VERSION),armv7-a)
PIXELFLINGER_SRC_FILES += col32cb16blend_neon.S
PIXELFLINGER_SRC_FILES += col32cb16blend.S
else
PIXELFLINGER_SRC_FILES += t32cb16blend.S
PIXELFLINGER_SRC_FILES += col32cb16blend.S
endif
endif
ifeq ($(TARGET_ARCH),arm)

78
libpixelflinger/col32cb16blend.S Normal file
View file

@ -0,0 +1,78 @@
/* libs/pixelflinger/col32cb16blend.S
**
** (C) COPYRIGHT 2009 ARM Limited.
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
**
*/
.text
.align
.global scanline_col32cb16blend_arm
//
// This function alpha blends a fixed color into a destination scanline, using
// the formula:
//
// d = s + (((a + (a >> 7)) * d) >> 8)
//
// where d is the destination pixel,
// s is the source color,
// a is the alpha channel of the source color.
//
// r0 = destination buffer pointer
// r1 = color value
// r2 = count
scanline_col32cb16blend_arm:
push {r4-r10, lr} // stack ARM regs
mov r5, r1, lsr #24 // shift down alpha
mov r9, #0xff // create mask
add r5, r5, r5, lsr #7 // add in top bit
rsb r5, r5, #256 // invert alpha
and r10, r1, #0xff // extract red
and r12, r9, r1, lsr #8 // extract green
and r4, r9, r1, lsr #16 // extract blue
mov r10, r10, lsl #5 // prescale red
mov r12, r12, lsl #6 // prescale green
mov r4, r4, lsl #5 // prescale blue
mov r9, r9, lsr #2 // create dest green mask
1:
ldrh r8, [r0] // load dest pixel
subs r2, r2, #1 // decrement loop counter
mov r6, r8, lsr #11 // extract dest red
and r7, r9, r8, lsr #5 // extract dest green
and r8, r8, #0x1f // extract dest blue
smlabb r6, r6, r5, r10 // dest red * alpha + src red
smlabb r7, r7, r5, r12 // dest green * alpha + src green
smlabb r8, r8, r5, r4 // dest blue * alpha + src blue
mov r6, r6, lsr #8 // shift down red
mov r7, r7, lsr #8 // shift down green
mov r6, r6, lsl #11 // shift red into 565
orr r6, r7, lsl #5 // shift green into 565
orr r6, r8, lsr #8 // shift blue into 565
strh r6, [r0], #2 // store pixel to dest, update ptr
bne 1b // if count != 0, loop
pop {r4-r10, pc} // return

153
libpixelflinger/col32cb16blend_neon.S Normal file
View file

@ -0,0 +1,153 @@
/* libs/pixelflinger/col32cb16blend_neon.S
**
** (C) COPYRIGHT 2009 ARM Limited.
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
**
*/
.text
.align
.global scanline_col32cb16blend_neon
//
// This function alpha blends a fixed color into a destination scanline, using
// the formula:
//
// d = s + (((a + (a >> 7)) * d) >> 8)
//
// where d is the destination pixel,
// s is the source color,
// a is the alpha channel of the source color.
//
// The NEON implementation processes 16 pixels per iteration. The remaining 0 - 15
// pixels are processed in ARM code.
//
// r0 = destination buffer pointer
// r1 = color pointer
// r2 = count
scanline_col32cb16blend_neon:
push {r4-r11, lr} // stack ARM regs
vmov.u16 q15, #256 // create alpha constant
movs r3, r2, lsr #4 // calc. sixteens iterations
vmov.u16 q14, #0x1f // create blue mask
beq 2f // if r3 == 0, branch to singles
vld4.8 {d0[], d2[], d4[], d6[]}, [r1] // load color into four registers
// split and duplicate them, such that
// d0 = 8 equal red values
// d2 = 8 equal green values
// d4 = 8 equal blue values
// d6 = 8 equal alpha values
vshll.u8 q0, d0, #5 // shift up red and widen
vshll.u8 q1, d2, #6 // shift up green and widen
vshll.u8 q2, d4, #5 // shift up blue and widen
vshr.u8 d7, d6, #7 // extract top bit of alpha
vaddl.u8 q3, d6, d7 // add top bit into alpha
vsub.u16 q3, q15, q3 // invert alpha
1:
// This loop processes 16 pixels per iteration. In the comments, references to
// the first eight pixels are suffixed with "0" (red0, green0, blue0),
// the second eight are suffixed "1".
// q8 = dst red0
// q9 = dst green0
// q10 = dst blue0
// q13 = dst red1
// q12 = dst green1
// q11 = dst blue1
vld1.16 {d20, d21, d22, d23}, [r0] // load 16 dest pixels
vshr.u16 q8, q10, #11 // shift dst red0 to low 5 bits
pld [r0, #63] // preload next dest pixels
vshl.u16 q9, q10, #5 // shift dst green0 to top 6 bits
vand q10, q10, q14 // extract dst blue0
vshr.u16 q9, q9, #10 // shift dst green0 to low 6 bits
vmul.u16 q8, q8, q3 // multiply dst red0 by src alpha
vshl.u16 q12, q11, #5 // shift dst green1 to top 6 bits
vmul.u16 q9, q9, q3 // multiply dst green0 by src alpha
vshr.u16 q13, q11, #11 // shift dst red1 to low 5 bits
vmul.u16 q10, q10, q3 // multiply dst blue0 by src alpha
vshr.u16 q12, q12, #10 // shift dst green1 to low 6 bits
vand q11, q11, q14 // extract dst blue1
vadd.u16 q8, q8, q0 // add src red to dst red0
vmul.u16 q13, q13, q3 // multiply dst red1 by src alpha
vadd.u16 q9, q9, q1 // add src green to dst green0
vmul.u16 q12, q12, q3 // multiply dst green1 by src alpha
vadd.u16 q10, q10, q2 // add src blue to dst blue0
vmul.u16 q11, q11, q3 // multiply dst blue1 by src alpha
vshr.u16 q8, q8, #8 // shift down red0
vadd.u16 q13, q13, q0 // add src red to dst red1
vshr.u16 q9, q9, #8 // shift down green0
vadd.u16 q12, q12, q1 // add src green to dst green1
vshr.u16 q10, q10, #8 // shift down blue0
vadd.u16 q11, q11, q2 // add src blue to dst blue1
vsli.u16 q10, q9, #5 // shift & insert green0 into blue0
vshr.u16 q13, q13, #8 // shift down red1
vsli.u16 q10, q8, #11 // shift & insert red0 into blue0
vshr.u16 q12, q12, #8 // shift down green1
vshr.u16 q11, q11, #8 // shift down blue1
subs r3, r3, #1 // decrement loop counter
vsli.u16 q11, q12, #5 // shift & insert green1 into blue1
vsli.u16 q11, q13, #11 // shift & insert red1 into blue1
vst1.16 {d20, d21, d22, d23}, [r0]! // write 16 pixels back to dst
bne 1b // if count != 0, loop
2:
ands r3, r2, #15 // calc. single iterations
beq 4f // if r3 == 0, exit
ldr r4, [r1] // load source color
mov r5, r4, lsr #24 // shift down alpha
add r5, r5, r5, lsr #7 // add in top bit
rsb r5, r5, #256 // invert alpha
and r11, r4, #0xff // extract red
ubfx r12, r4, #8, #8 // extract green
ubfx r4, r4, #16, #8 // extract blue
mov r11, r11, lsl #5 // prescale red
mov r12, r12, lsl #6 // prescale green
mov r4, r4, lsl #5 // prescale blue
3:
ldrh r8, [r0] // load dest pixel
subs r3, r3, #1 // decrement loop counter
mov r6, r8, lsr #11 // extract dest red
ubfx r7, r8, #5, #6 // extract dest green
and r8, r8, #0x1f // extract dest blue
smlabb r6, r6, r5, r11 // dest red * alpha + src red
smlabb r7, r7, r5, r12 // dest green * alpha + src green
smlabb r8, r8, r5, r4 // dest blue * alpha + src blue
mov r6, r6, lsr #8 // shift down red
mov r7, r7, lsr #8 // shift down green
mov r6, r6, lsl #11 // shift red into 565
orr r6, r7, lsl #5 // shift green into 565
orr r6, r8, lsr #8 // shift blue into 565
strh r6, [r0], #2 // store pixel to dest, update ptr
bne 3b // if count != 0, loop
4:
pop {r4-r11, pc} // return

47
libpixelflinger/scanline.cpp
View file

@ -80,6 +80,7 @@ static void scanline_perspective(context_t* c);
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 @@ static void rect_memcpy(context_t* c, size_t yc);
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 @@ static shortcut_t shortcuts[] = {
{ { { 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 @@ void init_y_packed(context_t* c, int32_t y0)
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 @@ finish:
// ----------------------------------------------------------------------------
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;