/* libs/pixelflinger/codeflinger/blending.cpp
**
** Copyright 2006, The Android Open Source Project
**
** 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.
*/
#define LOG_TAG "pixelflinger-code"
#include <assert.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <log/log.h>
#include "GGLAssembler.h"
namespace android {
void GGLAssembler::build_fog(
component_t& temp, // incomming fragment / output
int component,
Scratch& regs)
{
if (mInfo[component].fog) {
Scratch scratches(registerFile());
comment("fog");
integer_t fragment(temp.reg, temp.h, temp.flags);
if (!(temp.flags & CORRUPTIBLE)) {
temp.reg = regs.obtain();
temp.flags |= CORRUPTIBLE;
}
integer_t fogColor(scratches.obtain(), 8, CORRUPTIBLE);
LDRB(AL, fogColor.reg, mBuilderContext.Rctx,
immed12_pre(GGL_OFFSETOF(state.fog.color[component])));
integer_t factor(scratches.obtain(), 16, CORRUPTIBLE);
CONTEXT_LOAD(factor.reg, generated_vars.f);
// clamp fog factor (TODO: see if there is a way to guarantee
// we won't overflow, when setting the iterators)
BIC(AL, 0, factor.reg, factor.reg, reg_imm(factor.reg, ASR, 31));
CMP(AL, factor.reg, imm( 0x10000 ));
MOV(HS, 0, factor.reg, imm( 0x10000 ));
build_blendFOneMinusF(temp, factor, fragment, fogColor);
}
}
void GGLAssembler::build_blending(
component_t& temp, // incomming fragment / output
const pixel_t& pixel, // framebuffer
int component,
Scratch& regs)
{
if (!mInfo[component].blend)
return;
int fs = component==GGLFormat::ALPHA ? mBlendSrcA : mBlendSrc;
int fd = component==GGLFormat::ALPHA ? mBlendDstA : mBlendDst;
if (fs==GGL_SRC_ALPHA_SATURATE && component==GGLFormat::ALPHA)
fs = GGL_ONE;
const int blending = blending_codes(fs, fd);
if (!temp.size()) {
// here, blending will produce something which doesn't depend on
// that component (eg: GL_ZERO:GL_*), so the register has not been
// allocated yet. Will never be used as a source.
temp = component_t(regs.obtain(), CORRUPTIBLE);
}
// we are doing real blending...
// fb: extracted dst
// fragment: extracted src
// temp: component_t(fragment) and result
// scoped register allocator
Scratch scratches(registerFile());
comment("blending");
// we can optimize these cases a bit...
// (1) saturation is not needed
// (2) we can use only one multiply instead of 2
// (3) we can reduce the register pressure
// R = S*f + D*(1-f) = (S-D)*f + D
// R = S*(1-f) + D*f = (D-S)*f + S
const bool same_factor_opt1 =
(fs==GGL_DST_COLOR && fd==GGL_ONE_MINUS_DST_COLOR) ||
(fs==GGL_SRC_COLOR && fd==GGL_ONE_MINUS_SRC_COLOR) ||
(fs==GGL_DST_ALPHA && fd==GGL_ONE_MINUS_DST_ALPHA) ||
(fs==GGL_SRC_ALPHA && fd==GGL_ONE_MINUS_SRC_ALPHA);
const bool same_factor_opt2 =
(fs==GGL_ONE_MINUS_DST_COLOR && fd==GGL_DST_COLOR) ||
(fs==GGL_ONE_MINUS_SRC_COLOR && fd==GGL_SRC_COLOR) ||
(fs==GGL_ONE_MINUS_DST_ALPHA && fd==GGL_DST_ALPHA) ||
(fs==GGL_ONE_MINUS_SRC_ALPHA && fd==GGL_SRC_ALPHA);
// XXX: we could also optimize these cases:
// R = S*f + D*f = (S+D)*f
// R = S*(1-f) + D*(1-f) = (S+D)*(1-f)
// R = S*D + D*S = 2*S*D
// see if we need to extract 'component' from the destination (fb)
integer_t fb;
if (blending & (BLEND_DST|FACTOR_DST)) {
fb.setTo(scratches.obtain(), 32);
extract(fb, pixel, component);
if (mDithering) {
// XXX: maybe what we should do instead, is simply
// expand fb -or- fragment to the larger of the two
if (fb.size() < temp.size()) {
// for now we expand 'fb' to min(fragment, 8)
int new_size = temp.size() < 8 ? temp.size() : 8;
expand(fb, fb, new_size);
}
}
}
// convert input fragment to integer_t
if (temp.l && (temp.flags & CORRUPTIBLE)) {
MOV(AL, 0, temp.reg, reg_imm(temp.reg, LSR, temp.l));
temp.h -= temp.l;
temp.l = 0;
}
integer_t fragment(temp.reg, temp.size(), temp.flags);
// if not done yet, convert input fragment to integer_t
if (temp.l) {
// here we know temp is not CORRUPTIBLE
fragment.reg = scratches.obtain();
MOV(AL, 0, fragment.reg, reg_imm(temp.reg, LSR, temp.l));
fragment.flags |= CORRUPTIBLE;
}
if (!(temp.flags & CORRUPTIBLE)) {
// temp is not corruptible, but since it's the destination it
// will be modified, so we need to allocate a new register.
temp.reg = regs.obtain();
temp.flags &= ~CORRUPTIBLE;
fragment.flags &= ~CORRUPTIBLE;
}
if ((blending & BLEND_SRC) && !same_factor_opt1) {
// source (fragment) is needed for the blending stage
// so it's not CORRUPTIBLE (unless we're doing same_factor_opt1)
fragment.flags &= ~CORRUPTIBLE;
}
if (same_factor_opt1) {
// R = S*f + D*(1-f) = (S-D)*f + D
integer_t factor;
build_blend_factor(factor, fs,
component, pixel, fragment, fb, scratches);
// fb is always corruptible from this point
fb.flags |= CORRUPTIBLE;
build_blendFOneMinusF(temp, factor, fragment, fb);
} else if (same_factor_opt2) {
// R = S*(1-f) + D*f = (D-S)*f + S
integer_t factor;
// fb is always corrruptible here
fb.flags |= CORRUPTIBLE;
build_blend_factor(factor, fd,
component, pixel, fragment, fb, scratches);
build_blendOneMinusFF(temp, factor, fragment, fb);
} else {
integer_t src_factor;
integer_t dst_factor;
// if destination (fb) is not needed for the blending stage,
// then it can be marked as CORRUPTIBLE
if (!(blending & BLEND_DST)) {
fb.flags |= CORRUPTIBLE;
}
// XXX: try to mark some registers as CORRUPTIBLE
// in most case we could make those corruptible
// when we're processing the last component
// but not always, for instance
// when fragment is constant and not reloaded
// when fb is needed for logic-ops or masking
// when a register is aliased (for instance with mAlphaSource)
// blend away...
if (fs==GGL_ZERO) {
if (fd==GGL_ZERO) { // R = 0
// already taken care of
} else if (fd==GGL_ONE) { // R = D
// already taken care of
} else { // R = D*fd
// compute fd
build_blend_factor(dst_factor, fd,
component, pixel, fragment, fb, scratches);
mul_factor(temp, fb, dst_factor);
}
} else if (fs==GGL_ONE) {
if (fd==GGL_ZERO) { // R = S
// NOP, taken care of
} else if (fd==GGL_ONE) { // R = S + D
component_add(temp, fb, fragment); // args order matters
component_sat(temp);
} else { // R = S + D*fd
// compute fd
build_blend_factor(dst_factor, fd,
component, pixel, fragment, fb, scratches);
mul_factor_add(temp, fb, dst_factor, component_t(fragment));
component_sat(temp);
}
} else {
// compute fs
build_blend_factor(src_factor, fs,
component, pixel, fragment, fb, scratches);
if (fd==GGL_ZERO) { // R = S*fs
mul_factor(temp, fragment, src_factor);
} else if (fd==GGL_ONE) { // R = S*fs + D
mul_factor_add(temp, fragment, src_factor, component_t(fb));
component_sat(temp);
} else { // R = S*fs + D*fd
mul_factor(temp, fragment, src_factor);
if (scratches.isUsed(src_factor.reg))
scratches.recycle(src_factor.reg);
// compute fd
build_blend_factor(dst_factor, fd,
component, pixel, fragment, fb, scratches);
mul_factor_add(temp, fb, dst_factor, temp);
if (!same_factor_opt1 && !same_factor_opt2) {
component_sat(temp);
}
}
}
}
// now we can be corrupted (it's the dest)
temp.flags |= CORRUPTIBLE;
}
void GGLAssembler::build_blend_factor(
integer_t& factor, int f, int component,
const pixel_t& dst_pixel,
integer_t& fragment,
integer_t& fb,
Scratch& scratches)
{
integer_t src_alpha(fragment);
// src_factor/dst_factor won't be used after blending,
// so it's fine to mark them as CORRUPTIBLE (if not aliased)
factor.flags |= CORRUPTIBLE;
switch(f) {
case GGL_ONE_MINUS_SRC_ALPHA:
case GGL_SRC_ALPHA:
if (component==GGLFormat::ALPHA && !isAlphaSourceNeeded()) {
// we're processing alpha, so we already have
// src-alpha in fragment, and we need src-alpha just this time.
} else {
// alpha-src will be needed for other components
if (!mBlendFactorCached || mBlendFactorCached==f) {
src_alpha = mAlphaSource;
factor = mAlphaSource;
factor.flags &= ~CORRUPTIBLE;
// we already computed the blend factor before, nothing to do.
if (mBlendFactorCached)
return;
// this is the first time, make sure to compute the blend
// factor properly.
mBlendFactorCached = f;
break;
} else {
// we have a cached alpha blend factor, but we want another one,
// this should really not happen because by construction,
// we cannot have BOTH source and destination
// blend factors use ALPHA *and* ONE_MINUS_ALPHA (because
// the blending stage uses the f/(1-f) optimization
// for completeness, we handle this case though. Since there
// are only 2 choices, this meens we want "the other one"
// (1-factor)
factor = mAlphaSource;
factor.flags &= ~CORRUPTIBLE;
RSB(AL, 0, factor.reg, factor.reg, imm((1<<factor.s)));
mBlendFactorCached = f;
return;
}
}
// fall-through...
case GGL_ONE_MINUS_DST_COLOR:
case GGL_DST_COLOR:
case GGL_ONE_MINUS_SRC_COLOR:
case GGL_SRC_COLOR:
case GGL_ONE_MINUS_DST_ALPHA:
case GGL_DST_ALPHA:
case GGL_SRC_ALPHA_SATURATE:
// help us find out what register we can use for the blend-factor
// CORRUPTIBLE registers are chosen first, or a new one is allocated.
if (fragment.flags & CORRUPTIBLE) {
factor.setTo(fragment.reg, 32, CORRUPTIBLE);
fragment.flags &= ~CORRUPTIBLE;
} else if (fb.flags & CORRUPTIBLE) {
factor.setTo(fb.reg, 32, CORRUPTIBLE);
fb.flags &= ~CORRUPTIBLE;
} else {
factor.setTo(scratches.obtain(), 32, CORRUPTIBLE);
}
break;
}
// XXX: doesn't work if size==1
switch(f) {
case GGL_ONE_MINUS_DST_COLOR:
case GGL_DST_COLOR:
factor.s = fb.s;
ADD(AL, 0, factor.reg, fb.reg, reg_imm(fb.reg, LSR, fb.s-1));
break;
case GGL_ONE_MINUS_SRC_COLOR:
case GGL_SRC_COLOR:
factor.s = fragment.s;
ADD(AL, 0, factor.reg, fragment.reg,
reg_imm(fragment.reg, LSR, fragment.s-1));
break;
case GGL_ONE_MINUS_SRC_ALPHA:
case GGL_SRC_ALPHA:
factor.s = src_alpha.s;
ADD(AL, 0, factor.reg, src_alpha.reg,
reg_imm(src_alpha.reg, LSR, src_alpha.s-1));
break;
case GGL_ONE_MINUS_DST_ALPHA:
case GGL_DST_ALPHA:
// XXX: should be precomputed
extract(factor, dst_pixel, GGLFormat::ALPHA);
ADD(AL, 0, factor.reg, factor.reg,
reg_imm(factor.reg, LSR, factor.s-1));
break;
case GGL_SRC_ALPHA_SATURATE:
// XXX: should be precomputed
// XXX: f = min(As, 1-Ad)
// btw, we're guaranteed that Ad's size is <= 8, because
// it's extracted from the framebuffer
break;
}
switch(f) {
case GGL_ONE_MINUS_DST_COLOR:
case GGL_ONE_MINUS_SRC_COLOR:
case GGL_ONE_MINUS_DST_ALPHA:
case GGL_ONE_MINUS_SRC_ALPHA:
RSB(AL, 0, factor.reg, factor.reg, imm((1<<factor.s)));
}
// don't need more than 8-bits for the blend factor
// and this will prevent overflows in the multiplies later
if (factor.s > 8) {
MOV(AL, 0, factor.reg, reg_imm(factor.reg, LSR, factor.s-8));
factor.s = 8;
}
}
int GGLAssembler::blending_codes(int fs, int fd)
{
int blending = 0;
switch(fs) {
case GGL_ONE:
blending |= BLEND_SRC;
break;
case GGL_ONE_MINUS_DST_COLOR:
case GGL_DST_COLOR:
blending |= FACTOR_DST|BLEND_SRC;
break;
case GGL_ONE_MINUS_DST_ALPHA:
case GGL_DST_ALPHA:
// no need to extract 'component' from the destination
// for the blend factor, because we need ALPHA only.
blending |= BLEND_SRC;
break;
case GGL_ONE_MINUS_SRC_COLOR:
case GGL_SRC_COLOR:
blending |= FACTOR_SRC|BLEND_SRC;
break;
case GGL_ONE_MINUS_SRC_ALPHA:
case GGL_SRC_ALPHA:
case GGL_SRC_ALPHA_SATURATE:
blending |= FACTOR_SRC|BLEND_SRC;
break;
}
switch(fd) {
case GGL_ONE:
blending |= BLEND_DST;
break;
case GGL_ONE_MINUS_DST_COLOR:
case GGL_DST_COLOR:
blending |= FACTOR_DST|BLEND_DST;
break;
case GGL_ONE_MINUS_DST_ALPHA:
case GGL_DST_ALPHA:
blending |= FACTOR_DST|BLEND_DST;
break;
case GGL_ONE_MINUS_SRC_COLOR:
case GGL_SRC_COLOR:
blending |= FACTOR_SRC|BLEND_DST;
break;
case GGL_ONE_MINUS_SRC_ALPHA:
case GGL_SRC_ALPHA:
// no need to extract 'component' from the source
// for the blend factor, because we need ALPHA only.
blending |= BLEND_DST;
break;
}
return blending;
}
// ---------------------------------------------------------------------------
void GGLAssembler::build_blendFOneMinusF(
component_t& temp,
const integer_t& factor,
const integer_t& fragment,
const integer_t& fb)
{
// R = S*f + D*(1-f) = (S-D)*f + D
Scratch scratches(registerFile());
// compute S-D
integer_t diff(fragment.flags & CORRUPTIBLE ?
fragment.reg : scratches.obtain(), fb.size(), CORRUPTIBLE);
const int shift = fragment.size() - fb.size();
if (shift>0) RSB(AL, 0, diff.reg, fb.reg, reg_imm(fragment.reg, LSR, shift));
else if (shift<0) RSB(AL, 0, diff.reg, fb.reg, reg_imm(fragment.reg, LSL,-shift));
else RSB(AL, 0, diff.reg, fb.reg, fragment.reg);
mul_factor_add(temp, diff, factor, component_t(fb));
}
void GGLAssembler::build_blendOneMinusFF(
component_t& temp,
const integer_t& factor,
const integer_t& fragment,
const integer_t& fb)
{
// R = S*f + D*(1-f) = (S-D)*f + D
Scratch scratches(registerFile());
// compute D-S
integer_t diff(fb.flags & CORRUPTIBLE ?
fb.reg : scratches.obtain(), fb.size(), CORRUPTIBLE);
const int shift = fragment.size() - fb.size();
if (shift>0) SUB(AL, 0, diff.reg, fb.reg, reg_imm(fragment.reg, LSR, shift));
else if (shift<0) SUB(AL, 0, diff.reg, fb.reg, reg_imm(fragment.reg, LSL,-shift));
else SUB(AL, 0, diff.reg, fb.reg, fragment.reg);
mul_factor_add(temp, diff, factor, component_t(fragment));
}
// ---------------------------------------------------------------------------
void GGLAssembler::mul_factor( component_t& d,
const integer_t& v,
const integer_t& f)
{
int vs = v.size();
int fs = f.size();
int ms = vs+fs;
// XXX: we could have special cases for 1 bit mul
// all this code below to use the best multiply instruction
// wrt the parameters size. We take advantage of the fact
// that the 16-bits multiplies allow a 16-bit shift
// The trick is that we just make sure that we have at least 8-bits
// per component (which is enough for a 8 bits display).
int xy;
int vshift = 0;
int fshift = 0;
int smulw = 0;
if (vs<16) {
if (fs<16) {
xy = xyBB;
} else if (GGL_BETWEEN(fs, 24, 31)) {
ms -= 16;
xy = xyTB;
} else {
// eg: 15 * 18 -> 15 * 15
fshift = fs - 15;
ms -= fshift;
xy = xyBB;
}
} else if (GGL_BETWEEN(vs, 24, 31)) {
if (fs<16) {
ms -= 16;
xy = xyTB;
} else if (GGL_BETWEEN(fs, 24, 31)) {
ms -= 32;
xy = xyTT;
} else {
// eg: 24 * 18 -> 8 * 18
fshift = fs - 15;
ms -= 16 + fshift;
xy = xyTB;
}
} else {
if (fs<16) {
// eg: 18 * 15 -> 15 * 15
vshift = vs - 15;
ms -= vshift;
xy = xyBB;
} else if (GGL_BETWEEN(fs, 24, 31)) {
// eg: 18 * 24 -> 15 * 8
vshift = vs - 15;
ms -= 16 + vshift;
xy = xyBT;
} else {
// eg: 18 * 18 -> (15 * 18)>>16
fshift = fs - 15;
ms -= 16 + fshift;
xy = yB; //XXX SMULWB
smulw = 1;
}
}
ALOGE_IF(ms>=32, "mul_factor overflow vs=%d, fs=%d", vs, fs);
int vreg = v.reg;
int freg = f.reg;
if (vshift) {
MOV(AL, 0, d.reg, reg_imm(vreg, LSR, vshift));
vreg = d.reg;
}
if (fshift) {
MOV(AL, 0, d.reg, reg_imm(vreg, LSR, fshift));
freg = d.reg;
}
if (smulw) SMULW(AL, xy, d.reg, vreg, freg);
else SMUL(AL, xy, d.reg, vreg, freg);
d.h = ms;
if (mDithering) {
d.l = 0;
} else {
d.l = fs;
d.flags |= CLEAR_LO;
}
}
void GGLAssembler::mul_factor_add( component_t& d,
const integer_t& v,
const integer_t& f,
const component_t& a)
{
// XXX: we could have special cases for 1 bit mul
Scratch scratches(registerFile());
int vs = v.size();
int fs = f.size();
int as = a.h;
int ms = vs+fs;
ALOGE_IF(ms>=32, "mul_factor_add overflow vs=%d, fs=%d, as=%d", vs, fs, as);
integer_t add(a.reg, a.h, a.flags);
// 'a' is a component_t but it is guaranteed to have
// its high bits set to 0. However in the dithering case,
// we can't get away with truncating the potentially bad bits
// so extraction is needed.
if ((mDithering) && (a.size() < ms)) {
// we need to expand a
if (!(a.flags & CORRUPTIBLE)) {
// ... but it's not corruptible, so we need to pick a
// temporary register.
// Try to uses the destination register first (it's likely
// to be usable, unless it aliases an input).
if (d.reg!=a.reg && d.reg!=v.reg && d.reg!=f.reg) {
add.reg = d.reg;
} else {
add.reg = scratches.obtain();
}
}
expand(add, a, ms); // extracts and expands
as = ms;
}
if (ms == as) {
if (vs<16 && fs<16) SMLABB(AL, d.reg, v.reg, f.reg, add.reg);
else MLA(AL, 0, d.reg, v.reg, f.reg, add.reg);
} else {
int temp = d.reg;
if (temp == add.reg) {
// the mul will modify add.reg, we need an intermediary reg
if (v.flags & CORRUPTIBLE) temp = v.reg;
else if (f.flags & CORRUPTIBLE) temp = f.reg;
else temp = scratches.obtain();
}
if (vs<16 && fs<16) SMULBB(AL, temp, v.reg, f.reg);
else MUL(AL, 0, temp, v.reg, f.reg);
if (ms>as) {
ADD(AL, 0, d.reg, temp, reg_imm(add.reg, LSL, ms-as));
} else if (ms<as) {
// not sure if we should expand the mul instead?
ADD(AL, 0, d.reg, temp, reg_imm(add.reg, LSR, as-ms));
}
}
d.h = ms;
if (mDithering) {
d.l = a.l;
} else {
d.l = fs>a.l ? fs : a.l;
d.flags |= CLEAR_LO;
}
}
void GGLAssembler::component_add(component_t& d,
const integer_t& dst, const integer_t& src)
{
// here we're guaranteed that fragment.size() >= fb.size()
const int shift = src.size() - dst.size();
if (!shift) {
ADD(AL, 0, d.reg, src.reg, dst.reg);
} else {
ADD(AL, 0, d.reg, src.reg, reg_imm(dst.reg, LSL, shift));
}
d.h = src.size();
if (mDithering) {
d.l = 0;
} else {
d.l = shift;
d.flags |= CLEAR_LO;
}
}
void GGLAssembler::component_sat(const component_t& v)
{
const int one = ((1<<v.size())-1)<<v.l;
CMP(AL, v.reg, imm( 1<<v.h ));
if (isValidImmediate(one)) {
MOV(HS, 0, v.reg, imm( one ));
} else if (isValidImmediate(~one)) {
MVN(HS, 0, v.reg, imm( ~one ));
} else {
MOV(HS, 0, v.reg, imm( 1<<v.h ));
SUB(HS, 0, v.reg, v.reg, imm( 1<<v.l ));
}
}
// ----------------------------------------------------------------------------
}; // namespace android