1/* libs/pixelflinger/codeflinger/blending.cpp
2**
3** Copyright 2006, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18#include <assert.h>
19#include <stdint.h>
20#include <stdlib.h>
21#include <stdio.h>
22#include <sys/types.h>
23
24#include <cutils/log.h>
25
26#include "GGLAssembler.h"
27
28
29namespace android {
30
31void GGLAssembler::build_fog(
32                        component_t& temp,      // incomming fragment / output
33                        int component,
34                        Scratch& regs)
35{
36   if (mInfo[component].fog) {
37        Scratch scratches(registerFile());
38        comment("fog");
39
40        integer_t fragment(temp.reg, temp.h, temp.flags);
41        if (!(temp.flags & CORRUPTIBLE)) {
42            temp.reg = regs.obtain();
43            temp.flags |= CORRUPTIBLE;
44        }
45
46        integer_t fogColor(scratches.obtain(), 8, CORRUPTIBLE);
47        LDRB(AL, fogColor.reg, mBuilderContext.Rctx,
48                immed12_pre(GGL_OFFSETOF(state.fog.color[component])));
49
50        integer_t factor(scratches.obtain(), 16, CORRUPTIBLE);
51        CONTEXT_LOAD(factor.reg, generated_vars.f);
52
53        // clamp fog factor (TODO: see if there is a way to guarantee
54        // we won't overflow, when setting the iterators)
55        BIC(AL, 0, factor.reg, factor.reg, reg_imm(factor.reg, ASR, 31));
56        CMP(AL, factor.reg, imm( 0x10000 ));
57        MOV(HS, 0, factor.reg, imm( 0x10000 ));
58
59        build_blendFOneMinusF(temp, factor, fragment, fogColor);
60    }
61}
62
63void GGLAssembler::build_blending(
64                        component_t& temp,      // incomming fragment / output
65                        const pixel_t& pixel,   // framebuffer
66                        int component,
67                        Scratch& regs)
68{
69   if (!mInfo[component].blend)
70        return;
71
72    int fs = component==GGLFormat::ALPHA ? mBlendSrcA : mBlendSrc;
73    int fd = component==GGLFormat::ALPHA ? mBlendDstA : mBlendDst;
74    if (fs==GGL_SRC_ALPHA_SATURATE && component==GGLFormat::ALPHA)
75        fs = GGL_ONE;
76    const int blending = blending_codes(fs, fd);
77    if (!temp.size()) {
78        // here, blending will produce something which doesn't depend on
79        // that component (eg: GL_ZERO:GL_*), so the register has not been
80        // allocated yet. Will never be used as a source.
81        temp = component_t(regs.obtain(), CORRUPTIBLE);
82    }
83
84    // we are doing real blending...
85    // fb:          extracted dst
86    // fragment:    extracted src
87    // temp:        component_t(fragment) and result
88
89    // scoped register allocator
90    Scratch scratches(registerFile());
91    comment("blending");
92
93    // we can optimize these cases a bit...
94    // (1) saturation is not needed
95    // (2) we can use only one multiply instead of 2
96    // (3) we can reduce the register pressure
97    //      R = S*f + D*(1-f) = (S-D)*f + D
98    //      R = S*(1-f) + D*f = (D-S)*f + S
99
100    const bool same_factor_opt1 =
101        (fs==GGL_DST_COLOR && fd==GGL_ONE_MINUS_DST_COLOR) ||
102        (fs==GGL_SRC_COLOR && fd==GGL_ONE_MINUS_SRC_COLOR) ||
103        (fs==GGL_DST_ALPHA && fd==GGL_ONE_MINUS_DST_ALPHA) ||
104        (fs==GGL_SRC_ALPHA && fd==GGL_ONE_MINUS_SRC_ALPHA);
105
106    const bool same_factor_opt2 =
107        (fs==GGL_ONE_MINUS_DST_COLOR && fd==GGL_DST_COLOR) ||
108        (fs==GGL_ONE_MINUS_SRC_COLOR && fd==GGL_SRC_COLOR) ||
109        (fs==GGL_ONE_MINUS_DST_ALPHA && fd==GGL_DST_ALPHA) ||
110        (fs==GGL_ONE_MINUS_SRC_ALPHA && fd==GGL_SRC_ALPHA);
111
112
113    // XXX: we could also optimize these cases:
114    // R = S*f + D*f = (S+D)*f
115    // R = S*(1-f) + D*(1-f) = (S+D)*(1-f)
116    // R = S*D + D*S = 2*S*D
117
118
119    // see if we need to extract 'component' from the destination (fb)
120    integer_t fb;
121    if (blending & (BLEND_DST|FACTOR_DST)) {
122        fb.setTo(scratches.obtain(), 32);
123        extract(fb, pixel, component);
124        if (mDithering) {
125            // XXX: maybe what we should do instead, is simply
126            // expand fb -or- fragment to the larger of the two
127            if (fb.size() < temp.size()) {
128                // for now we expand 'fb' to min(fragment, 8)
129                int new_size = temp.size() < 8 ? temp.size() : 8;
130                expand(fb, fb, new_size);
131            }
132        }
133    }
134
135
136    // convert input fragment to integer_t
137    if (temp.l && (temp.flags & CORRUPTIBLE)) {
138        MOV(AL, 0, temp.reg, reg_imm(temp.reg, LSR, temp.l));
139        temp.h -= temp.l;
140        temp.l = 0;
141    }
142    integer_t fragment(temp.reg, temp.size(), temp.flags);
143
144    // if not done yet, convert input fragment to integer_t
145    if (temp.l) {
146        // here we know temp is not CORRUPTIBLE
147        fragment.reg = scratches.obtain();
148        MOV(AL, 0, fragment.reg, reg_imm(temp.reg, LSR, temp.l));
149        fragment.flags |= CORRUPTIBLE;
150    }
151
152    if (!(temp.flags & CORRUPTIBLE)) {
153        // temp is not corruptible, but since it's the destination it
154        // will be modified, so we need to allocate a new register.
155        temp.reg = regs.obtain();
156        temp.flags &= ~CORRUPTIBLE;
157        fragment.flags &= ~CORRUPTIBLE;
158    }
159
160    if ((blending & BLEND_SRC) && !same_factor_opt1) {
161        // source (fragment) is needed for the blending stage
162        // so it's not CORRUPTIBLE (unless we're doing same_factor_opt1)
163        fragment.flags &= ~CORRUPTIBLE;
164    }
165
166
167    if (same_factor_opt1) {
168        //  R = S*f + D*(1-f) = (S-D)*f + D
169        integer_t factor;
170        build_blend_factor(factor, fs,
171                component, pixel, fragment, fb, scratches);
172        // fb is always corruptible from this point
173        fb.flags |= CORRUPTIBLE;
174        build_blendFOneMinusF(temp, factor, fragment, fb);
175    } else if (same_factor_opt2) {
176        //  R = S*(1-f) + D*f = (D-S)*f + S
177        integer_t factor;
178        // fb is always corrruptible here
179        fb.flags |= CORRUPTIBLE;
180        build_blend_factor(factor, fd,
181                component, pixel, fragment, fb, scratches);
182        build_blendOneMinusFF(temp, factor, fragment, fb);
183    } else {
184        integer_t src_factor;
185        integer_t dst_factor;
186
187        // if destination (fb) is not needed for the blending stage,
188        // then it can be marked as CORRUPTIBLE
189        if (!(blending & BLEND_DST)) {
190            fb.flags |= CORRUPTIBLE;
191        }
192
193        // XXX: try to mark some registers as CORRUPTIBLE
194        // in most case we could make those corruptible
195        // when we're processing the last component
196        // but not always, for instance
197        //    when fragment is constant and not reloaded
198        //    when fb is needed for logic-ops or masking
199        //    when a register is aliased (for instance with mAlphaSource)
200
201        // blend away...
202        if (fs==GGL_ZERO) {
203            if (fd==GGL_ZERO) {         // R = 0
204                // already taken care of
205            } else if (fd==GGL_ONE) {   // R = D
206                // already taken care of
207            } else {                    // R = D*fd
208                // compute fd
209                build_blend_factor(dst_factor, fd,
210                        component, pixel, fragment, fb, scratches);
211                mul_factor(temp, fb, dst_factor);
212            }
213        } else if (fs==GGL_ONE) {
214            if (fd==GGL_ZERO) {         // R = S
215                // NOP, taken care of
216            } else if (fd==GGL_ONE) {   // R = S + D
217                component_add(temp, fb, fragment); // args order matters
218                component_sat(temp);
219            } else {                    // R = S + D*fd
220                // compute fd
221                build_blend_factor(dst_factor, fd,
222                        component, pixel, fragment, fb, scratches);
223                mul_factor_add(temp, fb, dst_factor, component_t(fragment));
224                component_sat(temp);
225            }
226        } else {
227            // compute fs
228            build_blend_factor(src_factor, fs,
229                    component, pixel, fragment, fb, scratches);
230            if (fd==GGL_ZERO) {         // R = S*fs
231                mul_factor(temp, fragment, src_factor);
232            } else if (fd==GGL_ONE) {   // R = S*fs + D
233                mul_factor_add(temp, fragment, src_factor, component_t(fb));
234                component_sat(temp);
235            } else {                    // R = S*fs + D*fd
236                mul_factor(temp, fragment, src_factor);
237                if (scratches.isUsed(src_factor.reg))
238                    scratches.recycle(src_factor.reg);
239                // compute fd
240                build_blend_factor(dst_factor, fd,
241                        component, pixel, fragment, fb, scratches);
242                mul_factor_add(temp, fb, dst_factor, temp);
243                if (!same_factor_opt1 && !same_factor_opt2) {
244                    component_sat(temp);
245                }
246            }
247        }
248    }
249
250    // now we can be corrupted (it's the dest)
251    temp.flags |= CORRUPTIBLE;
252}
253
254void GGLAssembler::build_blend_factor(
255        integer_t& factor, int f, int component,
256        const pixel_t& dst_pixel,
257        integer_t& fragment,
258        integer_t& fb,
259        Scratch& scratches)
260{
261    integer_t src_alpha(fragment);
262
263    // src_factor/dst_factor won't be used after blending,
264    // so it's fine to mark them as CORRUPTIBLE (if not aliased)
265    factor.flags |= CORRUPTIBLE;
266
267    switch(f) {
268    case GGL_ONE_MINUS_SRC_ALPHA:
269    case GGL_SRC_ALPHA:
270        if (component==GGLFormat::ALPHA && !isAlphaSourceNeeded()) {
271            // we're processing alpha, so we already have
272            // src-alpha in fragment, and we need src-alpha just this time.
273        } else {
274           // alpha-src will be needed for other components
275            if (!mBlendFactorCached || mBlendFactorCached==f) {
276                src_alpha = mAlphaSource;
277                factor = mAlphaSource;
278                factor.flags &= ~CORRUPTIBLE;
279                // we already computed the blend factor before, nothing to do.
280                if (mBlendFactorCached)
281                    return;
282                // this is the first time, make sure to compute the blend
283                // factor properly.
284                mBlendFactorCached = f;
285                break;
286            } else {
287                // we have a cached alpha blend factor, but we want another one,
288                // this should really not happen because by construction,
289                // we cannot have BOTH source and destination
290                // blend factors use ALPHA *and* ONE_MINUS_ALPHA (because
291                // the blending stage uses the f/(1-f) optimization
292
293                // for completeness, we handle this case though. Since there
294                // are only 2 choices, this meens we want "the other one"
295                // (1-factor)
296                factor = mAlphaSource;
297                factor.flags &= ~CORRUPTIBLE;
298                RSB(AL, 0, factor.reg, factor.reg, imm((1<<factor.s)));
299                mBlendFactorCached = f;
300                return;
301            }
302        }
303        // fall-through...
304    case GGL_ONE_MINUS_DST_COLOR:
305    case GGL_DST_COLOR:
306    case GGL_ONE_MINUS_SRC_COLOR:
307    case GGL_SRC_COLOR:
308    case GGL_ONE_MINUS_DST_ALPHA:
309    case GGL_DST_ALPHA:
310    case GGL_SRC_ALPHA_SATURATE:
311        // help us find out what register we can use for the blend-factor
312        // CORRUPTIBLE registers are chosen first, or a new one is allocated.
313        if (fragment.flags & CORRUPTIBLE) {
314            factor.setTo(fragment.reg, 32, CORRUPTIBLE);
315            fragment.flags &= ~CORRUPTIBLE;
316        } else if (fb.flags & CORRUPTIBLE) {
317            factor.setTo(fb.reg, 32, CORRUPTIBLE);
318            fb.flags &= ~CORRUPTIBLE;
319        } else {
320            factor.setTo(scratches.obtain(), 32, CORRUPTIBLE);
321        }
322        break;
323    }
324
325    // XXX: doesn't work if size==1
326
327    switch(f) {
328    case GGL_ONE_MINUS_DST_COLOR:
329    case GGL_DST_COLOR:
330        factor.s = fb.s;
331        ADD(AL, 0, factor.reg, fb.reg, reg_imm(fb.reg, LSR, fb.s-1));
332        break;
333    case GGL_ONE_MINUS_SRC_COLOR:
334    case GGL_SRC_COLOR:
335        factor.s = fragment.s;
336        ADD(AL, 0, factor.reg, fragment.reg,
337            reg_imm(fragment.reg, LSR, fragment.s-1));
338        break;
339    case GGL_ONE_MINUS_SRC_ALPHA:
340    case GGL_SRC_ALPHA:
341        factor.s = src_alpha.s;
342        ADD(AL, 0, factor.reg, src_alpha.reg,
343                reg_imm(src_alpha.reg, LSR, src_alpha.s-1));
344        break;
345    case GGL_ONE_MINUS_DST_ALPHA:
346    case GGL_DST_ALPHA:
347        // XXX: should be precomputed
348        extract(factor, dst_pixel, GGLFormat::ALPHA);
349        ADD(AL, 0, factor.reg, factor.reg,
350                reg_imm(factor.reg, LSR, factor.s-1));
351        break;
352    case GGL_SRC_ALPHA_SATURATE:
353        // XXX: should be precomputed
354        // XXX: f = min(As, 1-Ad)
355        // btw, we're guaranteed that Ad's size is <= 8, because
356        // it's extracted from the framebuffer
357        break;
358    }
359
360    switch(f) {
361    case GGL_ONE_MINUS_DST_COLOR:
362    case GGL_ONE_MINUS_SRC_COLOR:
363    case GGL_ONE_MINUS_DST_ALPHA:
364    case GGL_ONE_MINUS_SRC_ALPHA:
365        RSB(AL, 0, factor.reg, factor.reg, imm((1<<factor.s)));
366    }
367
368    // don't need more than 8-bits for the blend factor
369    // and this will prevent overflows in the multiplies later
370    if (factor.s > 8) {
371        MOV(AL, 0, factor.reg, reg_imm(factor.reg, LSR, factor.s-8));
372        factor.s = 8;
373    }
374}
375
376int GGLAssembler::blending_codes(int fs, int fd)
377{
378    int blending = 0;
379    switch(fs) {
380    case GGL_ONE:
381        blending |= BLEND_SRC;
382        break;
383
384    case GGL_ONE_MINUS_DST_COLOR:
385    case GGL_DST_COLOR:
386        blending |= FACTOR_DST|BLEND_SRC;
387        break;
388    case GGL_ONE_MINUS_DST_ALPHA:
389    case GGL_DST_ALPHA:
390        // no need to extract 'component' from the destination
391        // for the blend factor, because we need ALPHA only.
392        blending |= BLEND_SRC;
393        break;
394
395    case GGL_ONE_MINUS_SRC_COLOR:
396    case GGL_SRC_COLOR:
397        blending |= FACTOR_SRC|BLEND_SRC;
398        break;
399    case GGL_ONE_MINUS_SRC_ALPHA:
400    case GGL_SRC_ALPHA:
401    case GGL_SRC_ALPHA_SATURATE:
402        blending |= FACTOR_SRC|BLEND_SRC;
403        break;
404    }
405    switch(fd) {
406    case GGL_ONE:
407        blending |= BLEND_DST;
408        break;
409
410    case GGL_ONE_MINUS_DST_COLOR:
411    case GGL_DST_COLOR:
412        blending |= FACTOR_DST|BLEND_DST;
413        break;
414    case GGL_ONE_MINUS_DST_ALPHA:
415    case GGL_DST_ALPHA:
416        blending |= FACTOR_DST|BLEND_DST;
417        break;
418
419    case GGL_ONE_MINUS_SRC_COLOR:
420    case GGL_SRC_COLOR:
421        blending |= FACTOR_SRC|BLEND_DST;
422        break;
423    case GGL_ONE_MINUS_SRC_ALPHA:
424    case GGL_SRC_ALPHA:
425        // no need to extract 'component' from the source
426        // for the blend factor, because we need ALPHA only.
427        blending |= BLEND_DST;
428        break;
429    }
430    return blending;
431}
432
433// ---------------------------------------------------------------------------
434
435void GGLAssembler::build_blendFOneMinusF(
436        component_t& temp,
437        const integer_t& factor,
438        const integer_t& fragment,
439        const integer_t& fb)
440{
441    //  R = S*f + D*(1-f) = (S-D)*f + D
442    Scratch scratches(registerFile());
443    // compute S-D
444    integer_t diff(fragment.flags & CORRUPTIBLE ?
445            fragment.reg : scratches.obtain(), fb.size(), CORRUPTIBLE);
446    const int shift = fragment.size() - fb.size();
447    if (shift>0)        RSB(AL, 0, diff.reg, fb.reg, reg_imm(fragment.reg, LSR, shift));
448    else if (shift<0)   RSB(AL, 0, diff.reg, fb.reg, reg_imm(fragment.reg, LSL,-shift));
449    else                RSB(AL, 0, diff.reg, fb.reg, fragment.reg);
450    mul_factor_add(temp, diff, factor, component_t(fb));
451}
452
453void GGLAssembler::build_blendOneMinusFF(
454        component_t& temp,
455        const integer_t& factor,
456        const integer_t& fragment,
457        const integer_t& fb)
458{
459    //  R = S*f + D*(1-f) = (S-D)*f + D
460    Scratch scratches(registerFile());
461    // compute D-S
462    integer_t diff(fb.flags & CORRUPTIBLE ?
463            fb.reg : scratches.obtain(), fb.size(), CORRUPTIBLE);
464    const int shift = fragment.size() - fb.size();
465    if (shift>0)        SUB(AL, 0, diff.reg, fb.reg, reg_imm(fragment.reg, LSR, shift));
466    else if (shift<0)   SUB(AL, 0, diff.reg, fb.reg, reg_imm(fragment.reg, LSL,-shift));
467    else                SUB(AL, 0, diff.reg, fb.reg, fragment.reg);
468    mul_factor_add(temp, diff, factor, component_t(fragment));
469}
470
471// ---------------------------------------------------------------------------
472
473void GGLAssembler::mul_factor(  component_t& d,
474                                const integer_t& v,
475                                const integer_t& f)
476{
477    int vs = v.size();
478    int fs = f.size();
479    int ms = vs+fs;
480
481    // XXX: we could have special cases for 1 bit mul
482
483    // all this code below to use the best multiply instruction
484    // wrt the parameters size. We take advantage of the fact
485    // that the 16-bits multiplies allow a 16-bit shift
486    // The trick is that we just make sure that we have at least 8-bits
487    // per component (which is enough for a 8 bits display).
488
489    int xy;
490    int vshift = 0;
491    int fshift = 0;
492    int smulw = 0;
493
494    if (vs<16) {
495        if (fs<16) {
496            xy = xyBB;
497        } else if (GGL_BETWEEN(fs, 24, 31)) {
498            ms -= 16;
499            xy = xyTB;
500        } else {
501            // eg: 15 * 18  ->  15 * 15
502            fshift = fs - 15;
503            ms -= fshift;
504            xy = xyBB;
505        }
506    } else if (GGL_BETWEEN(vs, 24, 31)) {
507        if (fs<16) {
508            ms -= 16;
509            xy = xyTB;
510        } else if (GGL_BETWEEN(fs, 24, 31)) {
511            ms -= 32;
512            xy = xyTT;
513        } else {
514            // eg: 24 * 18  ->  8 * 18
515            fshift = fs - 15;
516            ms -= 16 + fshift;
517            xy = xyTB;
518        }
519    } else {
520        if (fs<16) {
521            // eg: 18 * 15  ->  15 * 15
522            vshift = vs - 15;
523            ms -= vshift;
524            xy = xyBB;
525        } else if (GGL_BETWEEN(fs, 24, 31)) {
526            // eg: 18 * 24  ->  15 * 8
527            vshift = vs - 15;
528            ms -= 16 + vshift;
529            xy = xyBT;
530        } else {
531            // eg: 18 * 18  ->  (15 * 18)>>16
532            fshift = fs - 15;
533            ms -= 16 + fshift;
534            xy = yB;    //XXX SMULWB
535            smulw = 1;
536        }
537    }
538
539    ALOGE_IF(ms>=32, "mul_factor overflow vs=%d, fs=%d", vs, fs);
540
541    int vreg = v.reg;
542    int freg = f.reg;
543    if (vshift) {
544        MOV(AL, 0, d.reg, reg_imm(vreg, LSR, vshift));
545        vreg = d.reg;
546    }
547    if (fshift) {
548        MOV(AL, 0, d.reg, reg_imm(vreg, LSR, fshift));
549        freg = d.reg;
550    }
551    if (smulw)  SMULW(AL, xy, d.reg, vreg, freg);
552    else        SMUL(AL, xy, d.reg, vreg, freg);
553
554
555    d.h = ms;
556    if (mDithering) {
557        d.l = 0;
558    } else {
559        d.l = fs;
560        d.flags |= CLEAR_LO;
561    }
562}
563
564void GGLAssembler::mul_factor_add(  component_t& d,
565                                    const integer_t& v,
566                                    const integer_t& f,
567                                    const component_t& a)
568{
569    // XXX: we could have special cases for 1 bit mul
570    Scratch scratches(registerFile());
571
572    int vs = v.size();
573    int fs = f.size();
574    int as = a.h;
575    int ms = vs+fs;
576
577    ALOGE_IF(ms>=32, "mul_factor_add overflow vs=%d, fs=%d, as=%d", vs, fs, as);
578
579    integer_t add(a.reg, a.h, a.flags);
580
581    // 'a' is a component_t but it is guaranteed to have
582    // its high bits set to 0. However in the dithering case,
583    // we can't get away with truncating the potentially bad bits
584    // so extraction is needed.
585
586   if ((mDithering) && (a.size() < ms)) {
587        // we need to expand a
588        if (!(a.flags & CORRUPTIBLE)) {
589            // ... but it's not corruptible, so we need to pick a
590            // temporary register.
591            // Try to uses the destination register first (it's likely
592            // to be usable, unless it aliases an input).
593            if (d.reg!=a.reg && d.reg!=v.reg && d.reg!=f.reg) {
594                add.reg = d.reg;
595            } else {
596                add.reg = scratches.obtain();
597            }
598        }
599        expand(add, a, ms); // extracts and expands
600        as = ms;
601    }
602
603    if (ms == as) {
604        if (vs<16 && fs<16) SMLABB(AL, d.reg, v.reg, f.reg, add.reg);
605        else                MLA(AL, 0, d.reg, v.reg, f.reg, add.reg);
606    } else {
607        int temp = d.reg;
608        if (temp == add.reg) {
609            // the mul will modify add.reg, we need an intermediary reg
610            if (v.flags & CORRUPTIBLE)      temp = v.reg;
611            else if (f.flags & CORRUPTIBLE) temp = f.reg;
612            else                            temp = scratches.obtain();
613        }
614
615        if (vs<16 && fs<16) SMULBB(AL, temp, v.reg, f.reg);
616        else                MUL(AL, 0, temp, v.reg, f.reg);
617
618        if (ms>as) {
619            ADD(AL, 0, d.reg, temp, reg_imm(add.reg, LSL, ms-as));
620        } else if (ms<as) {
621            // not sure if we should expand the mul instead?
622            ADD(AL, 0, d.reg, temp, reg_imm(add.reg, LSR, as-ms));
623        }
624    }
625
626    d.h = ms;
627    if (mDithering) {
628        d.l = a.l;
629    } else {
630        d.l = fs>a.l ? fs : a.l;
631        d.flags |= CLEAR_LO;
632    }
633}
634
635void GGLAssembler::component_add(component_t& d,
636        const integer_t& dst, const integer_t& src)
637{
638    // here we're guaranteed that fragment.size() >= fb.size()
639    const int shift = src.size() - dst.size();
640    if (!shift) {
641        ADD(AL, 0, d.reg, src.reg, dst.reg);
642    } else {
643        ADD(AL, 0, d.reg, src.reg, reg_imm(dst.reg, LSL, shift));
644    }
645
646    d.h = src.size();
647    if (mDithering) {
648        d.l = 0;
649    } else {
650        d.l = shift;
651        d.flags |= CLEAR_LO;
652    }
653}
654
655void GGLAssembler::component_sat(const component_t& v)
656{
657    const int one = ((1<<v.size())-1)<<v.l;
658    CMP(AL, v.reg, imm( 1<<v.h ));
659    if (isValidImmediate(one)) {
660        MOV(HS, 0, v.reg, imm( one ));
661    } else if (isValidImmediate(~one)) {
662        MVN(HS, 0, v.reg, imm( ~one ));
663    } else {
664        MOV(HS, 0, v.reg, imm( 1<<v.h ));
665        SUB(HS, 0, v.reg, v.reg, imm( 1<<v.l ));
666    }
667}
668
669// ----------------------------------------------------------------------------
670
671}; // namespace android
672
673