auto import from //depot/cupcake/@135843

1 files changed, 1496 insertions, 0 deletions

diff --git a/libpixelflinger/scanline.cpp b/libpixelflinger/scanline.cpp
new file mode 100644
index 00000000..f7003068
--- /dev/null
+++ b/libpixelflinger/scanline.cpp
@@ -0,0 +1,1496 @@
+/* libs/pixelflinger/scanline.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"
+
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <cutils/memory.h>
+#include <cutils/log.h>
+
+#include "buffer.h"
+#include "scanline.h"
+
+#include "codeflinger/CodeCache.h"
+#include "codeflinger/GGLAssembler.h"
+#include "codeflinger/ARMAssembler.h"
+//#include "codeflinger/ARMAssemblerOptimizer.h"
+
+// ----------------------------------------------------------------------------
+
+#define ANDROID_CODEGEN_GENERIC     0   // force generic pixel pipeline
+#define ANDROID_CODEGEN_C           1   // hand-written C, fallback generic 
+#define ANDROID_CODEGEN_ASM         2   // hand-written asm, fallback generic
+#define ANDROID_CODEGEN_GENERATED   3   // hand-written asm, fallback codegen
+
+#ifdef NDEBUG
+#   define ANDROID_RELEASE
+#   define ANDROID_CODEGEN      ANDROID_CODEGEN_GENERATED
+#else
+#   define ANDROID_DEBUG
+#   define ANDROID_CODEGEN      ANDROID_CODEGEN_GENERATED
+#endif
+
+#if defined(__arm__)
+#   define ANDROID_ARM_CODEGEN  1
+#else
+#   define ANDROID_ARM_CODEGEN  0
+#endif
+
+#define DEBUG__CODEGEN_ONLY     0
+
+
+#define ASSEMBLY_SCRATCH_SIZE   2048
+
+// ----------------------------------------------------------------------------
+namespace android {
+// ----------------------------------------------------------------------------
+
+static void init_y(context_t*, int32_t);
+static void init_y_noop(context_t*, int32_t);
+static void init_y_packed(context_t*, int32_t);
+static void init_y_error(context_t*, int32_t);
+
+static void step_y__generic(context_t* c);
+static void step_y__nop(context_t*);
+static void step_y__smooth(context_t* c);
+static void step_y__tmu(context_t* c);
+static void step_y__w(context_t* c);
+
+static void scanline(context_t* c);
+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_memcpy(context_t* c);
+static void scanline_memset8(context_t* c);
+static void scanline_memset16(context_t* c);
+static void scanline_memset32(context_t* c);
+static void scanline_noop(context_t* c);
+static void scanline_set(context_t* c);
+static void scanline_clear(context_t* c);
+
+static void rect_generic(context_t* c, size_t yc);
+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);
+
+// ----------------------------------------------------------------------------
+
+struct shortcut_t {
+    needs_filter_t  filter;
+    const char*     desc;
+    void            (*scanline)(context_t*);
+    void            (*init_y)(context_t*, int32_t);
+};
+
+// Keep in sync with needs
+static shortcut_t shortcuts[] = {
+    { { { 0x03515104, 0x00000077, { 0x00000A01, 0x00000000 } },
+        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
+        "565 fb, 8888 tx, blend", scanline_t32cb16blend, init_y_noop },
+    { { { 0x03010104, 0x00000077, { 0x00000A01, 0x00000000 } },
+        { 0xFFFFFFFF, 0xFFFFFFFF, { 0xFFFFFFFF, 0x0000003F } } },
+        "565 fb, 8888 tx", scanline_t32cb16, init_y_noop  },  
+    { { { 0x00000000, 0x00000000, { 0x00000000, 0x00000000 } },
+        { 0x00000000, 0x00000007, { 0x00000000, 0x00000000 } } },
+        "(nop) alpha test", scanline_noop, init_y_noop },
+    { { { 0x00000000, 0x00000000, { 0x00000000, 0x00000000 } },
+        { 0x00000000, 0x00000070, { 0x00000000, 0x00000000 } } },
+        "(nop) depth test", scanline_noop, init_y_noop },
+    { { { 0x05000000, 0x00000000, { 0x00000000, 0x00000000 } },
+        { 0x0F000000, 0x00000080, { 0x00000000, 0x00000000 } } },
+        "(nop) logic_op", scanline_noop, init_y_noop },
+    { { { 0xF0000000, 0x00000000, { 0x00000000, 0x00000000 } },
+        { 0xF0000000, 0x00000080, { 0x00000000, 0x00000000 } } },
+        "(nop) color mask", scanline_noop, init_y_noop },
+    { { { 0x0F000000, 0x00000077, { 0x00000000, 0x00000000 } },
+        { 0xFF000000, 0x000000F7, { 0x00000000, 0x00000000 } } },
+        "(set) logic_op", scanline_set, init_y_noop },
+    { { { 0x00000000, 0x00000077, { 0x00000000, 0x00000000 } },
+        { 0xFF000000, 0x000000F7, { 0x00000000, 0x00000000 } } },
+        "(clear) logic_op", scanline_clear, init_y_noop },
+    { { { 0x03000000, 0x00000077, { 0x00000000, 0x00000000 } },
+        { 0xFFFFFF00, 0x000000F7, { 0x00000000, 0x00000000 } } },
+        "(clear) blending 0/0", scanline_clear, init_y_noop },
+    { { { 0x00000000, 0x00000000, { 0x00000000, 0x00000000 } },
+        { 0x0000003F, 0x00000000, { 0x00000000, 0x00000000 } } },
+        "(error) invalid color-buffer format", scanline_noop, init_y_error },
+};
+static const needs_filter_t noblend1to1 = {
+        // (disregard dithering, see below)
+        { 0x03010100, 0x00000077, { 0x00000A00, 0x00000000 } },
+        { 0xFFFFFFC0, 0xFFFFFEFF, { 0xFFFFFFC0, 0x0000003F } }
+};
+static  const needs_filter_t fill16noblend = {
+        { 0x03010100, 0x00000077, { 0x00000000, 0x00000000 } },
+        { 0xFFFFFFC0, 0xFFFFFFFF, { 0x0000003F, 0x0000003F } }
+};
+
+// ----------------------------------------------------------------------------
+
+#if ANDROID_ARM_CODEGEN
+static CodeCache gCodeCache(12 * 1024);
+
+class ScanlineAssembly : public Assembly {
+    AssemblyKey<needs_t> mKey;
+public:
+    ScanlineAssembly(needs_t needs, size_t size)
+        : Assembly(size), mKey(needs) { }
+    const AssemblyKey<needs_t>& key() const { return mKey; }
+};
+#endif
+
+// ----------------------------------------------------------------------------
+
+void ggl_init_scanline(context_t* c)
+{
+    c->init_y = init_y;
+    c->step_y = step_y__generic;
+    c->scanline = scanline;
+}
+
+void ggl_uninit_scanline(context_t* c)
+{
+    if (c->state.buffers.coverage)
+        free(c->state.buffers.coverage);
+#if ANDROID_ARM_CODEGEN
+    if (c->scanline_as)
+        c->scanline_as->decStrong(c);
+#endif
+}
+
+// ----------------------------------------------------------------------------
+
+static void pick_scanline(context_t* c)
+{
+#if (!defined(DEBUG__CODEGEN_ONLY) || (DEBUG__CODEGEN_ONLY == 0))
+
+#if ANDROID_CODEGEN == ANDROID_CODEGEN_GENERIC
+    c->init_y = init_y;
+    c->step_y = step_y__generic;
+    c->scanline = scanline;
+    return;
+#endif
+
+    //printf("*** needs [%08lx:%08lx:%08lx:%08lx]\n",
+    //    c->state.needs.n, c->state.needs.p,
+    //    c->state.needs.t[0], c->state.needs.t[1]);
+
+    // first handle the special case that we cannot test with a filter
+    const uint32_t cb_format = GGL_READ_NEEDS(CB_FORMAT, c->state.needs.n);
+    if (GGL_READ_NEEDS(T_FORMAT, c->state.needs.t[0]) == cb_format) {
+        if (c->state.needs.match(noblend1to1)) {
+            // this will match regardless of dithering state, since both
+            // src and dest have the same format anyway, there is no dithering
+            // to be done.
+            const GGLFormat* f =
+                &(c->formats[GGL_READ_NEEDS(T_FORMAT, c->state.needs.t[0])]);
+            if ((f->components == GGL_RGB) ||
+                (f->components == GGL_RGBA) ||
+                (f->components == GGL_LUMINANCE) ||
+                (f->components == GGL_LUMINANCE_ALPHA))
+            {
+                // format must have all of RGB components
+                // (so the current color doesn't show through)
+                c->scanline = scanline_memcpy;
+                c->init_y = init_y_noop;
+                return;
+            }
+        }
+    }
+
+    if (c->state.needs.match(fill16noblend)) {
+        c->init_y = init_y_packed;
+        switch (c->formats[cb_format].size) {
+        case 1: c->scanline = scanline_memset8;  return;
+        case 2: c->scanline = scanline_memset16; return;
+        case 4: c->scanline = scanline_memset32; return;
+        }
+    }
+
+    const int numFilters = sizeof(shortcuts)/sizeof(shortcut_t);
+    for (int i=0 ; i<numFilters ; i++) {
+        if (c->state.needs.match(shortcuts[i].filter)) {
+            c->scanline = shortcuts[i].scanline;
+            c->init_y = shortcuts[i].init_y;
+            return;
+        }
+    }
+
+#endif // DEBUG__CODEGEN_ONLY
+
+    c->init_y = init_y;
+    c->step_y = step_y__generic;
+
+#if ANDROID_ARM_CODEGEN
+    // we're going to have to generate some code...
+    // here, generate code for our pixel pipeline
+    const AssemblyKey<needs_t> key(c->state.needs);
+    sp<Assembly> assembly = gCodeCache.lookup(key);
+    if (assembly == 0) {
+        // create a new assembly region
+        sp<ScanlineAssembly> a = new ScanlineAssembly(c->state.needs, 
+                ASSEMBLY_SCRATCH_SIZE);
+        // initialize our assembler
+        GGLAssembler assembler( new ARMAssembler(a) );
+        //GGLAssembler assembler(
+        //        new ARMAssemblerOptimizer(new ARMAssembler(a)) );
+        // generate the scanline code for the given needs
+        int err = assembler.scanline(c->state.needs, c);
+        if (ggl_likely(!err)) {
+            // finally, cache this assembly
+            err = gCodeCache.cache(a->key(), a);
+        }
+        if (ggl_unlikely(err)) {
+            LOGE("error generating or caching assembly. Reverting to NOP.");
+            c->scanline = scanline_noop;
+            c->init_y = init_y_noop;
+            c->step_y = step_y__nop;
+            return;
+        }
+        assembly = a;
+    }
+
+    // release the previous assembly
+    if (c->scanline_as) {
+        c->scanline_as->decStrong(c);
+    }
+
+    //LOGI("using generated pixel-pipeline");
+    c->scanline_as = assembly.get();
+    c->scanline_as->incStrong(c); //  hold on to assembly
+    c->scanline = (void(*)(context_t* c))assembly->base();
+#else
+//    LOGW("using generic (slow) pixel-pipeline");
+    c->scanline = scanline;
+#endif
+}
+
+void ggl_pick_scanline(context_t* c)
+{
+    pick_scanline(c);
+    if ((c->state.enables & GGL_ENABLE_W) &&
+        (c->state.enables & GGL_ENABLE_TMUS))
+    {
+        c->span = c->scanline;
+        c->scanline = scanline_perspective;
+        if (!(c->state.enabled_tmu & (c->state.enabled_tmu - 1))) {
+            // only one TMU enabled
+            c->scanline = scanline_perspective_single;
+        }
+    }
+}
+
+// ----------------------------------------------------------------------------
+
+static void blending(context_t* c, pixel_t* fragment, pixel_t* fb);
+static void blend_factor(context_t* c, pixel_t* r, uint32_t factor,
+        const pixel_t* src, const pixel_t* dst);
+static void rescale(uint32_t& u, uint8_t& su, uint32_t& v, uint8_t& sv);
+
+#if ANDROID_ARM_CODEGEN && (ANDROID_CODEGEN == ANDROID_CODEGEN_GENERATED)
+
+// no need to compile the generic-pipeline, it can't be reached
+void scanline(context_t*)
+{
+}
+
+#else
+
+void rescale(uint32_t& u, uint8_t& su, uint32_t& v, uint8_t& sv)
+{
+    if (su && sv) {
+        if (su > sv) {
+            v = ggl_expand(v, sv, su);
+            sv = su;
+        } else if (su < sv) {
+            u = ggl_expand(u, su, sv);
+            su = sv;
+        }
+    }
+}
+
+void blending(context_t* c, pixel_t* fragment, pixel_t* fb)
+{
+    rescale(fragment->c[0], fragment->s[0], fb->c[0], fb->s[0]);
+    rescale(fragment->c[1], fragment->s[1], fb->c[1], fb->s[1]);
+    rescale(fragment->c[2], fragment->s[2], fb->c[2], fb->s[2]);
+    rescale(fragment->c[3], fragment->s[3], fb->c[3], fb->s[3]);
+
+    pixel_t sf, df;
+    blend_factor(c, &sf, c->state.blend.src, fragment, fb);
+    blend_factor(c, &df, c->state.blend.dst, fragment, fb);
+
+    fragment->c[1] =
+            gglMulAddx(fragment->c[1], sf.c[1], gglMulx(fb->c[1], df.c[1]));
+    fragment->c[2] =
+            gglMulAddx(fragment->c[2], sf.c[2], gglMulx(fb->c[2], df.c[2]));
+    fragment->c[3] =
+            gglMulAddx(fragment->c[3], sf.c[3], gglMulx(fb->c[3], df.c[3]));
+
+    if (c->state.blend.alpha_separate) {
+        blend_factor(c, &sf, c->state.blend.src_alpha, fragment, fb);
+        blend_factor(c, &df, c->state.blend.dst_alpha, fragment, fb);
+    }
+
+    fragment->c[0] =
+            gglMulAddx(fragment->c[0], sf.c[0], gglMulx(fb->c[0], df.c[0]));
+
+    // clamp to 1.0
+    if (fragment->c[0] >= (1LU<<fragment->s[0]))
+        fragment->c[0] = (1<<fragment->s[0])-1;
+    if (fragment->c[1] >= (1LU<<fragment->s[1]))
+        fragment->c[1] = (1<<fragment->s[1])-1;
+    if (fragment->c[2] >= (1LU<<fragment->s[2]))
+        fragment->c[2] = (1<<fragment->s[2])-1;
+    if (fragment->c[3] >= (1LU<<fragment->s[3]))
+        fragment->c[3] = (1<<fragment->s[3])-1;
+}
+
+static inline int blendfactor(uint32_t x, uint32_t size, uint32_t def = 0)
+{
+    if (!size)
+        return def;
+
+    // scale to 16 bits
+    if (size > 16) {
+        x >>= (size - 16);
+    } else if (size < 16) {
+        x = ggl_expand(x, size, 16);
+    }
+    x += x >> 15;
+    return x;
+}
+
+void blend_factor(context_t* c, pixel_t* r, 
+        uint32_t factor, const pixel_t* src, const pixel_t* dst)
+{
+    switch (factor) {
+        case GGL_ZERO:
+            r->c[1] = 
+            r->c[2] = 
+            r->c[3] = 
+            r->c[0] = 0;
+            break;
+        case GGL_ONE:
+            r->c[1] = 
+            r->c[2] = 
+            r->c[3] = 
+            r->c[0] = FIXED_ONE;
+            break;
+        case GGL_DST_COLOR:
+            r->c[1] = blendfactor(dst->c[1], dst->s[1]);
+            r->c[2] = blendfactor(dst->c[2], dst->s[2]);
+            r->c[3] = blendfactor(dst->c[3], dst->s[3]);
+            r->c[0] = blendfactor(dst->c[0], dst->s[0]);
+            break;
+        case GGL_SRC_COLOR:
+            r->c[1] = blendfactor(src->c[1], src->s[1]);
+            r->c[2] = blendfactor(src->c[2], src->s[2]);
+            r->c[3] = blendfactor(src->c[3], src->s[3]);
+            r->c[0] = blendfactor(src->c[0], src->s[0]);
+            break;
+        case GGL_ONE_MINUS_DST_COLOR:
+            r->c[1] = FIXED_ONE - blendfactor(dst->c[1], dst->s[1]);
+            r->c[2] = FIXED_ONE - blendfactor(dst->c[2], dst->s[2]);
+            r->c[3] = FIXED_ONE - blendfactor(dst->c[3], dst->s[3]);
+            r->c[0] = FIXED_ONE - blendfactor(dst->c[0], dst->s[0]);
+            break;
+        case GGL_ONE_MINUS_SRC_COLOR:
+            r->c[1] = FIXED_ONE - blendfactor(src->c[1], src->s[1]);
+            r->c[2] = FIXED_ONE - blendfactor(src->c[2], src->s[2]);
+            r->c[3] = FIXED_ONE - blendfactor(src->c[3], src->s[3]);
+            r->c[0] = FIXED_ONE - blendfactor(src->c[0], src->s[0]);
+            break;
+        case GGL_SRC_ALPHA:
+            r->c[1] = 
+            r->c[2] = 
+            r->c[3] = 
+            r->c[0] = blendfactor(src->c[0], src->s[0], FIXED_ONE);
+            break;
+        case GGL_ONE_MINUS_SRC_ALPHA:
+            r->c[1] = 
+            r->c[2] = 
+            r->c[3] = 
+            r->c[0] = FIXED_ONE - blendfactor(src->c[0], src->s[0], FIXED_ONE);
+            break;
+        case GGL_DST_ALPHA:
+            r->c[1] = 
+            r->c[2] = 
+            r->c[3] = 
+            r->c[0] = blendfactor(dst->c[0], dst->s[0], FIXED_ONE);
+            break;
+        case GGL_ONE_MINUS_DST_ALPHA:
+            r->c[1] = 
+            r->c[2] = 
+            r->c[3] = 
+            r->c[0] = FIXED_ONE - blendfactor(dst->c[0], dst->s[0], FIXED_ONE);
+            break;
+        case GGL_SRC_ALPHA_SATURATE:
+            // XXX: GGL_SRC_ALPHA_SATURATE
+            break;
+    }
+}
+
+static GGLfixed wrapping(int32_t coord, uint32_t size, int tx_wrap)
+{
+    GGLfixed d;
+    if (tx_wrap == GGL_REPEAT) {
+        d = (uint32_t(coord)>>16) * size;
+    } else if (tx_wrap == GGL_CLAMP) { // CLAMP_TO_EDGE semantics
+        const GGLfixed clamp_min = FIXED_HALF;
+        const GGLfixed clamp_max = (size << 16) - FIXED_HALF;
+        if (coord < clamp_min)     coord = clamp_min;
+        if (coord > clamp_max)     coord = clamp_max;
+        d = coord;
+    } else { // 1:1
+        const GGLfixed clamp_min = 0;
+        const GGLfixed clamp_max = (size << 16);
+        if (coord < clamp_min)     coord = clamp_min;
+        if (coord > clamp_max)     coord = clamp_max;
+        d = coord;
+    }
+    return d;
+}
+
+static inline
+GGLcolor ADJUST_COLOR_ITERATOR(GGLcolor v, GGLcolor dvdx, int len)
+{
+    const int32_t end = dvdx * (len-1) + v;
+    if (end < 0)
+        v -= end;
+    v &= ~(v>>31);
+    return v;
+}
+
+void scanline(context_t* c)
+{
+    const uint32_t enables = c->state.enables;
+    const int xs = c->iterators.xl;
+    const int x1 = c->iterators.xr;
+	int xc = x1 - xs;
+    const int16_t* covPtr = c->state.buffers.coverage + xs;
+
+    // All iterated values are sampled at the pixel center
+
+    // reset iterators for that scanline...
+    GGLcolor r, g, b, a;
+    iterators_t& ci = c->iterators;
+    if (enables & GGL_ENABLE_SMOOTH) {
+        r = (xs * c->shade.drdx) + ci.ydrdy;
+        g = (xs * c->shade.dgdx) + ci.ydgdy;
+        b = (xs * c->shade.dbdx) + ci.ydbdy;
+        a = (xs * c->shade.dadx) + ci.ydady;
+        r = ADJUST_COLOR_ITERATOR(r, c->shade.drdx, xc);
+        g = ADJUST_COLOR_ITERATOR(g, c->shade.dgdx, xc);
+        b = ADJUST_COLOR_ITERATOR(b, c->shade.dbdx, xc);
+        a = ADJUST_COLOR_ITERATOR(a, c->shade.dadx, xc);
+    } else {
+        r = ci.ydrdy;
+        g = ci.ydgdy;
+        b = ci.ydbdy;
+        a = ci.ydady;
+    }
+
+    // z iterators are 1.31
+    GGLfixed z = (xs * c->shade.dzdx) + ci.ydzdy;
+    GGLfixed f = (xs * c->shade.dfdx) + ci.ydfdy;
+
+    struct {
+        GGLfixed s, t;
+    } tc[GGL_TEXTURE_UNIT_COUNT];
+    if (enables & GGL_ENABLE_TMUS) {
+        for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
+            if (c->state.texture[i].enable) {
+                texture_iterators_t& ti = c->state.texture[i].iterators;
+                if (enables & GGL_ENABLE_W) {
+                    tc[i].s = ti.ydsdy;
+                    tc[i].t = ti.ydtdy;
+                } else {
+                    tc[i].s = (xs * ti.dsdx) + ti.ydsdy;
+                    tc[i].t = (xs * ti.dtdx) + ti.ydtdy;
+                }
+            }
+        }
+    }
+
+    pixel_t fragment;
+    pixel_t texel;
+    pixel_t fb;
+
+	uint32_t x = xs;
+	uint32_t y = c->iterators.y;
+
+	while (xc--) {
+    
+        { // just a scope
+
+		// read color (convert to 8 bits by keeping only the integer part)
+        fragment.s[1] = fragment.s[2] =
+        fragment.s[3] = fragment.s[0] = 8;
+        fragment.c[1] = r >> (GGL_COLOR_BITS-8);
+        fragment.c[2] = g >> (GGL_COLOR_BITS-8);
+        fragment.c[3] = b >> (GGL_COLOR_BITS-8);
+        fragment.c[0] = a >> (GGL_COLOR_BITS-8);
+
+		// texturing
+        if (enables & GGL_ENABLE_TMUS) {
+            for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
+                texture_t& tx = c->state.texture[i];
+                if (!tx.enable)
+                    continue;
+                texture_iterators_t& ti = tx.iterators;
+                int32_t u, v;
+
+                // s-coordinate
+                if (tx.s_coord != GGL_ONE_TO_ONE) {
+                    const int w = tx.surface.width;
+                    u = wrapping(tc[i].s, w, tx.s_wrap);
+                    tc[i].s += ti.dsdx;
+                } else {
+                    u = (((tx.shade.is0>>16) + x)<<16) + FIXED_HALF;
+                }
+
+                // t-coordinate
+                if (tx.t_coord != GGL_ONE_TO_ONE) {
+                    const int h = tx.surface.height;
+                    v = wrapping(tc[i].t, h, tx.t_wrap);
+                    tc[i].t += ti.dtdx;
+                } else {
+                    v = (((tx.shade.it0>>16) + y)<<16) + FIXED_HALF;
+                }
+
+                // read texture
+                if (tx.mag_filter == GGL_NEAREST &&
+                    tx.min_filter == GGL_NEAREST)
+                {
+                    u >>= 16;
+                    v >>= 16;
+                    tx.surface.read(&tx.surface, c, u, v, &texel);
+                } else {
+                    const int w = tx.surface.width;
+                    const int h = tx.surface.height;
+                    u -= FIXED_HALF;
+                    v -= FIXED_HALF;
+                    int u0 = u >> 16;
+                    int v0 = v >> 16;
+                    int u1 = u0 + 1;
+                    int v1 = v0 + 1;
+                    if (tx.s_wrap == GGL_REPEAT) {
+                        if (u0<0)  u0 += w;
+                        if (u1<0)  u1 += w;
+                        if (u0>=w) u0 -= w;
+                        if (u1>=w) u1 -= w;
+                    } else {
+                        if (u0<0)  u0 = 0;
+                        if (u1<0)  u1 = 0;
+                        if (u0>=w) u0 = w-1;
+                        if (u1>=w) u1 = w-1;
+                    }
+                    if (tx.t_wrap == GGL_REPEAT) {
+                        if (v0<0)  v0 += h;
+                        if (v1<0)  v1 += h;
+                        if (v0>=h) v0 -= h;
+                        if (v1>=h) v1 -= h;
+                    } else {
+                        if (v0<0)  v0 = 0;
+                        if (v1<0)  v1 = 0;
+                        if (v0>=h) v0 = h-1;
+                        if (v1>=h) v1 = h-1;
+                    }
+                    pixel_t texels[4];
+                    uint32_t mm[4];
+                    tx.surface.read(&tx.surface, c, u0, v0, &texels[0]);
+                    tx.surface.read(&tx.surface, c, u0, v1, &texels[1]);
+                    tx.surface.read(&tx.surface, c, u1, v0, &texels[2]);
+                    tx.surface.read(&tx.surface, c, u1, v1, &texels[3]);
+                    u = (u >> 12) & 0xF; 
+                    v = (v >> 12) & 0xF;
+                    u += u>>3;
+                    v += v>>3;
+                    mm[0] = (0x10 - u) * (0x10 - v);
+                    mm[1] = (0x10 - u) * v;
+                    mm[2] = u * (0x10 - v);
+                    mm[3] = 0x100 - (mm[0] + mm[1] + mm[2]);
+                    for (int j=0 ; j<4 ; j++) {
+                        texel.s[j] = texels[0].s[j];
+                        if (!texel.s[j]) continue;
+                        texel.s[j] += 8;
+                        texel.c[j] =    texels[0].c[j]*mm[0] +
+                                        texels[1].c[j]*mm[1] +
+                                        texels[2].c[j]*mm[2] +
+                                        texels[3].c[j]*mm[3] ;
+                    }
+                }
+
+                // Texture environnement...
+                for (int j=0 ; j<4 ; j++) {
+                    uint32_t& Cf = fragment.c[j];
+                    uint32_t& Ct = texel.c[j];
+                    uint8_t& sf  = fragment.s[j];
+                    uint8_t& st  = texel.s[j];
+                    uint32_t At = texel.c[0];
+                    uint8_t sat = texel.s[0];
+                    switch (tx.env) {
+                    case GGL_REPLACE:
+                        if (st) {
+                            Cf = Ct;
+                            sf = st;
+                        }
+                        break;
+                    case GGL_MODULATE:
+                        if (st) {
+                            uint32_t factor = Ct + (Ct>>(st-1));
+                            Cf = (Cf * factor) >> st;
+                        }
+                        break;
+                    case GGL_DECAL:
+                        if (sat) {
+                            rescale(Cf, sf, Ct, st);
+                            Cf += ((Ct - Cf) * (At + (At>>(sat-1)))) >> sat;
+                        }
+                        break;
+                    case GGL_BLEND:
+                        if (st) {
+                            uint32_t Cc = tx.env_color[i];
+                            if (sf>8)       Cc = (Cc * ((1<<sf)-1))>>8;
+                            else if (sf<8)  Cc = (Cc - (Cc>>(8-sf)))>>(8-sf);
+                            uint32_t factor = Ct + (Ct>>(st-1));
+                            Cf = ((((1<<st) - factor) * Cf) + Ct*Cc)>>st;
+                        }
+                        break;
+                    case GGL_ADD:
+                        if (st) {
+                            rescale(Cf, sf, Ct, st);
+                            Cf += Ct;
+                        }
+                        break;
+                    }
+                }
+            }
+		}
+    
+        // coverage application
+        if (enables & GGL_ENABLE_AA) {
+            int16_t cf = *covPtr++;
+            fragment.c[0] = (int64_t(fragment.c[0]) * cf) >> 15;
+        }
+        
+        // alpha-test
+        if (enables & GGL_ENABLE_ALPHA_TEST) {
+            GGLcolor ref = c->state.alpha_test.ref;
+            GGLcolor alpha = (uint64_t(fragment.c[0]) *
+                    ((1<<GGL_COLOR_BITS)-1)) / ((1<<fragment.s[0])-1);
+            switch (c->state.alpha_test.func) {
+            case GGL_NEVER:     goto discard;
+            case GGL_LESS:      if (alpha<ref)  break; goto discard;
+            case GGL_EQUAL:     if (alpha==ref) break; goto discard;
+            case GGL_LEQUAL:    if (alpha<=ref) break; goto discard;
+            case GGL_GREATER:   if (alpha>ref)  break; goto discard;
+            case GGL_NOTEQUAL:  if (alpha!=ref) break; goto discard;
+            case GGL_GEQUAL:    if (alpha>=ref) break; goto discard;
+            }
+        }
+        
+        // depth test
+        if (c->state.buffers.depth.format) {
+            if (enables & GGL_ENABLE_DEPTH_TEST) {
+                surface_t* cb = &(c->state.buffers.depth);
+                uint16_t* p = (uint16_t*)(cb->data)+(x+(cb->stride*y));
+                uint16_t zz = uint32_t(z)>>(16);
+                uint16_t depth = *p;
+                switch (c->state.depth_test.func) {
+                case GGL_NEVER:     goto discard;
+                case GGL_LESS:      if (zz<depth)    break; goto discard;
+                case GGL_EQUAL:     if (zz==depth)   break; goto discard;
+                case GGL_LEQUAL:    if (zz<=depth)   break; goto discard;
+                case GGL_GREATER:   if (zz>depth)    break; goto discard;
+                case GGL_NOTEQUAL:  if (zz!=depth)   break; goto discard;
+                case GGL_GEQUAL:    if (zz>=depth)   break; goto discard;
+                }
+                // depth buffer is not enabled, if depth-test is not enabled
+/*
+        fragment.s[1] = fragment.s[2] =
+        fragment.s[3] = fragment.s[0] = 8;
+        fragment.c[1] = 
+        fragment.c[2] = 
+        fragment.c[3] = 
+        fragment.c[0] = 255 - (zz>>8);
+*/
+                if (c->state.mask.depth) {
+                    *p = zz;
+                }
+            }
+        }
+
+        // fog
+        if (enables & GGL_ENABLE_FOG) {
+            for (int i=1 ; i<=3 ; i++) {
+                GGLfixed fc = (c->state.fog.color[i] * 0x10000) / 0xFF;
+                uint32_t& c = fragment.c[i];
+                uint8_t& s  = fragment.s[i];
+                c = (c * 0x10000) / ((1<<s)-1);
+                c = gglMulAddx(c, f, gglMulx(fc, 0x10000 - f));
+                s = 16;
+            }
+        }
+
+        // blending
+        if (enables & GGL_ENABLE_BLENDING) {
+            fb.c[1] = fb.c[2] = fb.c[3] = fb.c[0] = 0; // placate valgrind
+            fb.s[1] = fb.s[2] = fb.s[3] = fb.s[0] = 0;
+            c->state.buffers.color.read(
+                    &(c->state.buffers.color), c, x, y, &fb);
+            blending( c, &fragment, &fb );
+        }
+
+		// write
+        c->state.buffers.color.write(
+                &(c->state.buffers.color), c, x, y, &fragment);
+        }
+
+discard:
+		// iterate...
+        x += 1;
+        if (enables & GGL_ENABLE_SMOOTH) {
+            r += c->shade.drdx;
+            g += c->shade.dgdx;
+            b += c->shade.dbdx;
+            a += c->shade.dadx;
+        }
+        z += c->shade.dzdx;
+        f += c->shade.dfdx;
+	}
+}
+
+#endif // ANDROID_ARM_CODEGEN && (ANDROID_CODEGEN == ANDROID_CODEGEN_GENERATED)
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#pragma mark Scanline
+#endif
+
+template <typename T, typename U>
+static inline __attribute__((const))
+T interpolate(int y, T v0, U dvdx, U dvdy) {
+    // interpolates in pixel's centers
+    // v = v0 + (y + 0.5) * dvdy + (0.5 * dvdx)
+    return (y * dvdy) + (v0 + ((dvdy + dvdx) >> 1));
+}
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#endif
+
+void init_y(context_t* c, int32_t ys)
+{
+    const uint32_t enables = c->state.enables;
+
+    // compute iterators...
+    iterators_t& ci = c->iterators;
+    
+    // sample in the center
+    ci.y = ys;
+
+    if (enables & (GGL_ENABLE_DEPTH_TEST|GGL_ENABLE_W|GGL_ENABLE_FOG)) {
+        ci.ydzdy = interpolate(ys, c->shade.z0, c->shade.dzdx, c->shade.dzdy);
+        ci.ydwdy = interpolate(ys, c->shade.w0, c->shade.dwdx, c->shade.dwdy);
+        ci.ydfdy = interpolate(ys, c->shade.f0, c->shade.dfdx, c->shade.dfdy);
+    }
+
+    if (ggl_unlikely(enables & GGL_ENABLE_SMOOTH)) {
+        ci.ydrdy = interpolate(ys, c->shade.r0, c->shade.drdx, c->shade.drdy);
+        ci.ydgdy = interpolate(ys, c->shade.g0, c->shade.dgdx, c->shade.dgdy);
+        ci.ydbdy = interpolate(ys, c->shade.b0, c->shade.dbdx, c->shade.dbdy);
+        ci.ydady = interpolate(ys, c->shade.a0, c->shade.dadx, c->shade.dady);
+        c->step_y = step_y__smooth;
+    } else {
+        ci.ydrdy = c->shade.r0;
+        ci.ydgdy = c->shade.g0;
+        ci.ydbdy = c->shade.b0;
+        ci.ydady = c->shade.a0;
+        // XXX: do only if needed, or make sure this is fast
+        c->packed = ggl_pack_color(c, c->state.buffers.color.format,
+                ci.ydrdy, ci.ydgdy, ci.ydbdy, ci.ydady);
+        c->packed8888 = ggl_pack_color(c, GGL_PIXEL_FORMAT_RGBA_8888, 
+                ci.ydrdy, ci.ydgdy, ci.ydbdy, ci.ydady);
+    }
+
+    // initialize the variables we need in the shader
+    generated_vars_t& gen = c->generated_vars;
+    gen.argb[GGLFormat::ALPHA].c  = ci.ydady;
+    gen.argb[GGLFormat::ALPHA].dx = c->shade.dadx;
+    gen.argb[GGLFormat::RED  ].c  = ci.ydrdy;
+    gen.argb[GGLFormat::RED  ].dx = c->shade.drdx;
+    gen.argb[GGLFormat::GREEN].c  = ci.ydgdy;
+    gen.argb[GGLFormat::GREEN].dx = c->shade.dgdx;
+    gen.argb[GGLFormat::BLUE ].c  = ci.ydbdy;
+    gen.argb[GGLFormat::BLUE ].dx = c->shade.dbdx;
+    gen.dzdx = c->shade.dzdx;
+    gen.f    = ci.ydfdy;
+    gen.dfdx = c->shade.dfdx;
+
+    if (enables & GGL_ENABLE_TMUS) {
+        for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
+            texture_t& t = c->state.texture[i];
+            if (!t.enable) continue;
+
+            texture_iterators_t& ti = t.iterators;
+            if (t.s_coord == GGL_ONE_TO_ONE && t.t_coord == GGL_ONE_TO_ONE) {
+                // we need to set all of these to 0 because in some cases
+                // step_y__generic() or step_y__tmu() will be used and
+                // therefore will update dtdy, however, in 1:1 mode
+                // this is always done by the scanline rasterizer.
+                ti.dsdx = ti.dsdy = ti.dtdx = ti.dtdy = 0;
+                ti.ydsdy = t.shade.is0;
+                ti.ydtdy = t.shade.it0;
+            } else {
+                const int adjustSWrap = ((t.s_wrap==GGL_CLAMP)?0:16);
+                const int adjustTWrap = ((t.t_wrap==GGL_CLAMP)?0:16);
+                ti.sscale = t.shade.sscale + adjustSWrap;
+                ti.tscale = t.shade.tscale + adjustTWrap;
+                if (!(enables & GGL_ENABLE_W)) {
+                    // S coordinate
+                    const int32_t sscale = ti.sscale;
+                    const int32_t sy = interpolate(ys,
+                            t.shade.is0, t.shade.idsdx, t.shade.idsdy);
+                    if (sscale>=0) {
+                        ti.ydsdy= sy            << sscale;
+                        ti.dsdx = t.shade.idsdx << sscale; 
+                        ti.dsdy = t.shade.idsdy << sscale;
+                    } else {
+                        ti.ydsdy= sy            >> -sscale;
+                        ti.dsdx = t.shade.idsdx >> -sscale; 
+                        ti.dsdy = t.shade.idsdy >> -sscale;
+                    }
+                    // T coordinate
+                    const int32_t tscale = ti.tscale;
+                    const int32_t ty = interpolate(ys,
+                            t.shade.it0, t.shade.idtdx, t.shade.idtdy);
+                    if (tscale>=0) {
+                        ti.ydtdy= ty            << tscale;
+                        ti.dtdx = t.shade.idtdx << tscale; 
+                        ti.dtdy = t.shade.idtdy << tscale;
+                    } else {
+                        ti.ydtdy= ty            >> -tscale;
+                        ti.dtdx = t.shade.idtdx >> -tscale; 
+                        ti.dtdy = t.shade.idtdy >> -tscale;
+                    }
+                }
+            }
+            // mirror for generated code...
+            generated_tex_vars_t& gen = c->generated_vars.texture[i];
+            gen.width   = t.surface.width;
+            gen.height  = t.surface.height;
+            gen.stride  = t.surface.stride;
+            gen.data    = int32_t(t.surface.data);
+            gen.dsdx = ti.dsdx;
+            gen.dtdx = ti.dtdx;
+        }
+    }
+
+    // choose the y-stepper
+    c->step_y = step_y__nop;
+    if (enables & GGL_ENABLE_FOG) {
+        c->step_y = step_y__generic;
+    } else if (enables & GGL_ENABLE_TMUS) {
+        if (enables & GGL_ENABLE_SMOOTH) {
+            c->step_y = step_y__generic;
+        } else if (enables & GGL_ENABLE_W) {
+            c->step_y = step_y__w;
+        } else {
+            c->step_y = step_y__tmu;
+        }
+    } else {
+        if (enables & GGL_ENABLE_SMOOTH) {
+            c->step_y = step_y__smooth;
+        }
+    }
+    
+    // choose the rectangle blitter
+    c->rect = rect_generic;
+    if ((c->step_y == step_y__nop) &&
+        (c->scanline == scanline_memcpy))
+    {
+        c->rect = rect_memcpy;
+    }
+}
+
+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->iterators.y = y0;
+    c->step_y = step_y__nop;
+    // choose the rectangle blitter
+    c->rect = rect_generic;
+    if (c->scanline == scanline_memcpy) {
+        c->rect = rect_memcpy;
+    }
+}
+
+void init_y_noop(context_t* c, int32_t y0)
+{
+    c->iterators.y = y0;
+    c->step_y = step_y__nop;
+    // choose the rectangle blitter
+    c->rect = rect_generic;
+    if (c->scanline == scanline_memcpy) {
+        c->rect = rect_memcpy;
+    }
+}
+
+void init_y_error(context_t* c, int32_t y0)
+{
+    // woooops, shoud never happen,
+    // fail gracefully (don't display anything)
+    init_y_noop(c, y0);
+    LOGE("color-buffer has an invalid format!");
+}
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#endif
+
+void step_y__generic(context_t* c)
+{
+    const uint32_t enables = c->state.enables;
+
+    // iterate...
+    iterators_t& ci = c->iterators;
+    ci.y += 1;
+                
+    if (enables & GGL_ENABLE_SMOOTH) {
+        ci.ydrdy += c->shade.drdy;
+        ci.ydgdy += c->shade.dgdy;
+        ci.ydbdy += c->shade.dbdy;
+        ci.ydady += c->shade.dady;
+    }
+
+    const uint32_t mask =
+            GGL_ENABLE_DEPTH_TEST |
+            GGL_ENABLE_W |
+            GGL_ENABLE_FOG;
+    if (enables & mask) {
+        ci.ydzdy += c->shade.dzdy;
+        ci.ydwdy += c->shade.dwdy;
+        ci.ydfdy += c->shade.dfdy;
+    }
+
+    if ((enables & GGL_ENABLE_TMUS) && (!(enables & GGL_ENABLE_W))) {
+        for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
+            if (c->state.texture[i].enable) {
+                texture_iterators_t& ti = c->state.texture[i].iterators;
+                ti.ydsdy += ti.dsdy;
+                ti.ydtdy += ti.dtdy;
+            }
+        }
+    }
+}
+
+void step_y__nop(context_t* c)
+{
+    c->iterators.y += 1;
+    c->iterators.ydzdy += c->shade.dzdy;
+}
+
+void step_y__smooth(context_t* c)
+{
+    iterators_t& ci = c->iterators;
+    ci.y += 1;
+    ci.ydrdy += c->shade.drdy;
+    ci.ydgdy += c->shade.dgdy;
+    ci.ydbdy += c->shade.dbdy;
+    ci.ydady += c->shade.dady;
+    ci.ydzdy += c->shade.dzdy;
+}
+
+void step_y__w(context_t* c)
+{
+    iterators_t& ci = c->iterators;
+    ci.y += 1;
+    ci.ydzdy += c->shade.dzdy;
+    ci.ydwdy += c->shade.dwdy;
+}
+
+void step_y__tmu(context_t* c)
+{
+    iterators_t& ci = c->iterators;
+    ci.y += 1;
+    ci.ydzdy += c->shade.dzdy;
+    for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
+        if (c->state.texture[i].enable) {
+            texture_iterators_t& ti = c->state.texture[i].iterators;
+            ti.ydsdy += ti.dsdy;
+            ti.ydtdy += ti.dtdy;
+        }
+    }
+}
+
+// ----------------------------------------------------------------------------
+#if 0
+#pragma mark -
+#endif
+
+void scanline_perspective(context_t* c)
+{
+    struct {
+        union {
+            struct {
+                int32_t s, sq;
+                int32_t t, tq;
+            };
+            struct {
+                int32_t v, q;
+            } st[2];
+        };
+    } tc[GGL_TEXTURE_UNIT_COUNT] __attribute__((aligned(16)));
+
+    // XXX: we should have a special case when dwdx = 0
+
+    // 32 pixels spans works okay. 16 is a lot better,
+    // but hey, it's a software renderer...
+    const uint32_t SPAN_BITS = 5; 
+    const uint32_t ys = c->iterators.y;
+    const uint32_t xs = c->iterators.xl;
+    const uint32_t x1 = c->iterators.xr;
+	const uint32_t xc = x1 - xs;
+    uint32_t remainder = xc & ((1<<SPAN_BITS)-1);
+    uint32_t numSpans = xc >> SPAN_BITS;
+
+    const iterators_t& ci = c->iterators;
+    int32_t w0 = (xs * c->shade.dwdx) + ci.ydwdy;
+    int32_t q0 = gglRecipQ(w0, 30);
+    const int iwscale = 32 - gglClz(q0);
+
+    const int32_t dwdx = c->shade.dwdx << SPAN_BITS;
+    int32_t xl = c->iterators.xl;
+
+    // We process s & t with a loop to reduce the code size
+    // (and i-cache pressure).
+
+    for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
+        const texture_t& tmu = c->state.texture[i];
+        if (!tmu.enable) continue;
+        int32_t s =   tmu.shade.is0 +
+                     (tmu.shade.idsdy * ys) + (tmu.shade.idsdx * xs) +
+                     ((tmu.shade.idsdx + tmu.shade.idsdy)>>1);
+        int32_t t =   tmu.shade.it0 +
+                     (tmu.shade.idtdy * ys) + (tmu.shade.idtdx * xs) +
+                     ((tmu.shade.idtdx + tmu.shade.idtdy)>>1);
+        tc[i].s  = s;
+        tc[i].t  = t;
+        tc[i].sq = gglMulx(s, q0, iwscale);
+        tc[i].tq = gglMulx(t, q0, iwscale);
+    }
+
+    int32_t span = 0;
+    do {
+        int32_t w1;
+        if (ggl_likely(numSpans)) {
+            w1 = w0 + dwdx;
+        } else {
+            if (remainder) {
+                // finish off the scanline...
+                span = remainder;
+                w1 = (c->shade.dwdx * span) + w0;
+            } else {
+                break;
+            }
+        }
+        int32_t q1 = gglRecipQ(w1, 30);
+        for (int i=0 ; i<GGL_TEXTURE_UNIT_COUNT ; ++i) {
+            texture_t& tmu = c->state.texture[i];
+            if (!tmu.enable) continue;
+            texture_iterators_t& ti = tmu.iterators;
+
+            for (int j=0 ; j<2 ; j++) {
+                int32_t v = tc[i].st[j].v;
+                if (span)   v += (tmu.shade.st[j].dx)*span;
+                else        v += (tmu.shade.st[j].dx)<<SPAN_BITS;
+                const int32_t v0 = tc[i].st[j].q;
+                const int32_t v1 = gglMulx(v, q1, iwscale);
+                int32_t dvdx = v1 - v0;
+                if (span)   dvdx /= span;
+                else        dvdx >>= SPAN_BITS;
+                tc[i].st[j].v = v;
+                tc[i].st[j].q = v1;
+
+                const int scale = ti.st[j].scale + (iwscale - 30);
+                if (scale >= 0) {
+                    ti.st[j].ydvdy = v0   << scale;
+                    ti.st[j].dvdx  = dvdx << scale;
+                } else {
+                    ti.st[j].ydvdy = v0   >> -scale;
+                    ti.st[j].dvdx  = dvdx >> -scale;
+                }
+            }
+            generated_tex_vars_t& gen = c->generated_vars.texture[i];
+            gen.dsdx = ti.st[0].dvdx;
+            gen.dtdx = ti.st[1].dvdx;
+        }
+        c->iterators.xl = xl;
+        c->iterators.xr = xl = xl + (span ? span : (1<<SPAN_BITS));
+        w0 = w1;
+        q0 = q1;
+        c->span(c);
+    } while(numSpans--);
+}
+
+void scanline_perspective_single(context_t* c)
+{
+    // 32 pixels spans works okay. 16 is a lot better,
+    // but hey, it's a software renderer...
+    const uint32_t SPAN_BITS = 5; 
+    const uint32_t ys = c->iterators.y;
+    const uint32_t xs = c->iterators.xl;
+    const uint32_t x1 = c->iterators.xr;
+	const uint32_t xc = x1 - xs;
+
+    const iterators_t& ci = c->iterators;
+    int32_t w = (xs * c->shade.dwdx) + ci.ydwdy;
+    int32_t iw = gglRecipQ(w, 30);
+    const int iwscale = 32 - gglClz(iw);
+
+    const int i = 31 - gglClz(c->state.enabled_tmu);
+    generated_tex_vars_t& gen = c->generated_vars.texture[i];
+    texture_t& tmu = c->state.texture[i];
+    texture_iterators_t& ti = tmu.iterators;
+    const int sscale = ti.sscale + (iwscale - 30);
+    const int tscale = ti.tscale + (iwscale - 30);
+    int32_t s =   tmu.shade.is0 +
+                 (tmu.shade.idsdy * ys) + (tmu.shade.idsdx * xs) +
+                 ((tmu.shade.idsdx + tmu.shade.idsdy)>>1);
+    int32_t t =   tmu.shade.it0 +
+                 (tmu.shade.idtdy * ys) + (tmu.shade.idtdx * xs) +
+                 ((tmu.shade.idtdx + tmu.shade.idtdy)>>1);
+    int32_t s0 = gglMulx(s, iw, iwscale);
+    int32_t t0 = gglMulx(t, iw, iwscale);
+    int32_t xl = c->iterators.xl;
+
+    int32_t sq, tq, dsdx, dtdx;
+    int32_t premainder = xc & ((1<<SPAN_BITS)-1);
+    uint32_t numSpans = xc >> SPAN_BITS;
+    if (c->shade.dwdx == 0) {
+        // XXX: we could choose to do this if the error is small enough
+        numSpans = 0;
+        premainder = xc;
+        goto no_perspective;
+    }
+
+    if (premainder) {
+        w += c->shade.dwdx   * premainder;
+        iw = gglRecipQ(w, 30);
+no_perspective:        
+        s += tmu.shade.idsdx * premainder;
+        t += tmu.shade.idtdx * premainder;
+        sq = gglMulx(s, iw, iwscale);
+        tq = gglMulx(t, iw, iwscale);
+        dsdx = (sq - s0) / premainder;
+        dtdx = (tq - t0) / premainder;
+        c->iterators.xl = xl;
+        c->iterators.xr = xl = xl + premainder;
+        goto finish;
+    }
+
+    while (numSpans--) {
+        w += c->shade.dwdx   << SPAN_BITS;
+        s += tmu.shade.idsdx << SPAN_BITS;
+        t += tmu.shade.idtdx << SPAN_BITS;
+        iw = gglRecipQ(w, 30);
+        sq = gglMulx(s, iw, iwscale);
+        tq = gglMulx(t, iw, iwscale);
+        dsdx = (sq - s0) >> SPAN_BITS;
+        dtdx = (tq - t0) >> SPAN_BITS;
+        c->iterators.xl = xl;
+        c->iterators.xr = xl = xl + (1<<SPAN_BITS);
+finish:
+        if (sscale >= 0) {
+            ti.ydsdy = s0   << sscale;
+            ti.dsdx  = dsdx << sscale;
+        } else {
+            ti.ydsdy = s0   >>-sscale;
+            ti.dsdx  = dsdx >>-sscale;
+        }
+        if (tscale >= 0) {
+            ti.ydtdy = t0   << tscale;
+            ti.dtdx  = dtdx << tscale;
+        } else {
+            ti.ydtdy = t0   >>-tscale;
+            ti.dtdx  = dtdx >>-tscale;
+        }
+        s0 = sq;
+        t0 = tq;
+        gen.dsdx = ti.dsdx;
+        gen.dtdx = ti.dtdx;
+        c->span(c);
+    }
+}
+
+// ----------------------------------------------------------------------------
+
+void scanline_t32cb16(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));
+
+    surface_t* tex = &(c->state.texture[0].surface);
+    const int32_t u = (c->state.texture[0].shade.is0>>16) + x;
+    const int32_t v = (c->state.texture[0].shade.it0>>16) + y;
+    uint32_t *src = reinterpret_cast<uint32_t*>(tex->data)+(u+(tex->stride*v));
+    int sR, sG, sB;
+    uint32_t s, d;
+
+    if (ct==1 || uint32_t(dst)&2) {
+last_one:
+        s = GGL_RGBA_TO_HOST( *src++ );
+        sR = (s >> (   3))&0x1F;
+        sG = (s >> ( 8+2))&0x3F;
+        sB = (s >> (16+3))&0x1F;
+        *dst++ = uint16_t((sR<<11)|(sG<<5)|sB);
+        ct--;
+    }
+
+    while (ct >= 2) {
+        s = GGL_RGBA_TO_HOST( *src++ );
+        sR = (s >> (   3))&0x1F;
+        sG = (s >> ( 8+2))&0x3F;
+        sB = (s >> (16+3))&0x1F;
+        d = (sR<<11)|(sG<<5)|sB;
+        
+        s = GGL_RGBA_TO_HOST( *src++ );
+        sR = (s >> (   3))&0x1F;
+        sG = (s >> ( 8+2))&0x3F;
+        sB = (s >> (16+3))&0x1F;        
+        d |= ((sR<<11)|(sG<<5)|sB)<<16;
+
+#if BYTE_ORDER == BIG_ENDIAN
+        d = (d>>16) | (d<<16);
+#endif
+
+        *dst32++ = d;
+        ct -= 2;
+    }
+    
+    if (ct > 0) {
+        goto last_one;
+    }
+}
+
+void scanline_t32cb16blend(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);
+    uint16_t* dst = reinterpret_cast<uint16_t*>(cb->data) + (x+(cb->stride*y));
+
+    surface_t* tex = &(c->state.texture[0].surface);
+    const int32_t u = (c->state.texture[0].shade.is0>>16) + x;
+    const int32_t v = (c->state.texture[0].shade.it0>>16) + y;
+    uint32_t *src = reinterpret_cast<uint32_t*>(tex->data)+(u+(tex->stride*v));
+
+#if ((ANDROID_CODEGEN >= ANDROID_CODEGEN_ASM) && defined(__arm__))
+    scanline_t32cb16blend_arm(dst, src, ct);
+#else
+    while (ct--) {
+        uint32_t s = *src++;
+        if (!s) {
+            dst++;
+            continue;
+        }
+        uint16_t d = *dst;
+        s = GGL_RGBA_TO_HOST(s);
+        int sR = (s >> (   3))&0x1F;
+        int sG = (s >> ( 8+2))&0x3F;
+        int sB = (s >> (16+3))&0x1F;
+        int sA = (s>>24);
+        int f = 0x100 - (sA + (sA>>7));
+        int dR = (d>>11)&0x1f;
+        int dG = (d>>5)&0x3f;
+        int dB = (d)&0x1f;
+        sR += (f*dR)>>8;
+        sG += (f*dG)>>8;
+        sB += (f*dB)>>8;
+        *dst++ = uint16_t((sR<<11)|(sG<<5)|sB);
+    }
+#endif
+}
+
+void scanline_memcpy(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);
+    const GGLFormat* fp = &(c->formats[cb->format]);
+    uint8_t* dst = reinterpret_cast<uint8_t*>(cb->data) +
+                            (x + (cb->stride * y)) * fp->size;
+
+    surface_t* tex = &(c->state.texture[0].surface);
+    const int32_t u = (c->state.texture[0].shade.is0>>16) + x;
+    const int32_t v = (c->state.texture[0].shade.it0>>16) + y;
+    uint8_t *src = reinterpret_cast<uint8_t*>(tex->data) +
+                            (u + (tex->stride * v)) * fp->size;
+
+    const size_t size = ct * fp->size;
+    memcpy(dst, src, size);
+}
+
+void scanline_memset8(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);
+    uint8_t* dst = reinterpret_cast<uint8_t*>(cb->data) + (x+(cb->stride*y));
+    uint32_t packed = c->packed;
+    memset(dst, packed, ct);
+}
+
+void scanline_memset16(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);
+    uint16_t* dst = reinterpret_cast<uint16_t*>(cb->data) + (x+(cb->stride*y));
+    uint32_t packed = c->packed;
+    android_memset16(dst, packed, ct*2);
+}
+
+void scanline_memset32(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);
+    uint32_t* dst = reinterpret_cast<uint32_t*>(cb->data) + (x+(cb->stride*y));
+    uint32_t packed = GGL_HOST_TO_RGBA(c->packed);
+    android_memset32(dst, packed, ct*4);
+}
+
+void scanline_clear(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);
+    const GGLFormat* fp = &(c->formats[cb->format]);
+    uint8_t* dst = reinterpret_cast<uint8_t*>(cb->data) +
+                            (x + (cb->stride * y)) * fp->size;
+    const size_t size = ct * fp->size;
+    memset(dst, 0, size);
+}
+
+void scanline_set(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);
+    const GGLFormat* fp = &(c->formats[cb->format]);
+    uint8_t* dst = reinterpret_cast<uint8_t*>(cb->data) +
+                            (x + (cb->stride * y)) * fp->size;
+    const size_t size = ct * fp->size;
+    memset(dst, 0xFF, size);
+}
+
+void scanline_noop(context_t* c)
+{
+}
+
+void rect_generic(context_t* c, size_t yc)
+{
+    do {
+        c->scanline(c);
+        c->step_y(c);
+    } while (--yc);
+}
+
+void rect_memcpy(context_t* c, size_t yc)
+{
+    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);
+    const GGLFormat* fp = &(c->formats[cb->format]);
+    uint8_t* dst = reinterpret_cast<uint8_t*>(cb->data) +
+                            (x + (cb->stride * y)) * fp->size;
+
+    surface_t* tex = &(c->state.texture[0].surface);
+    const int32_t u = (c->state.texture[0].shade.is0>>16) + x;
+    const int32_t v = (c->state.texture[0].shade.it0>>16) + y;
+    uint8_t *src = reinterpret_cast<uint8_t*>(tex->data) +
+                            (u + (tex->stride * v)) * fp->size;
+
+    if (cb->stride == tex->stride && ct == size_t(cb->stride)) {
+        memcpy(dst, src, ct * fp->size * yc);
+    } else {
+        const size_t size = ct * fp->size;
+        const size_t dbpr = cb->stride  * fp->size;
+        const size_t sbpr = tex->stride * fp->size;
+        do {
+            memcpy(dst, src, size);
+            dst += dbpr;
+            src += sbpr;        
+        } while (--yc);
+    }
+}
+// ----------------------------------------------------------------------------
+}; // namespace android
+
+using namespace android;
+extern "C" void ggl_test_codegen(uint32_t n, uint32_t p, uint32_t t0, uint32_t t1)
+{
+#if ANDROID_ARM_CODEGEN
+    GGLContext* c;
+    gglInit(&c);
+    needs_t needs;
+    needs.n = n;
+    needs.p = p;
+    needs.t[0] = t0;
+    needs.t[1] = t1;
+    sp<ScanlineAssembly> a(new ScanlineAssembly(needs, ASSEMBLY_SCRATCH_SIZE));
+    GGLAssembler assembler( new ARMAssembler(a) );
+    int err = assembler.scanline(needs, (context_t*)c);
+    if (err != 0) {
+        printf("error %08x (%s)\n", err, strerror(-err));
+    }
+    gglUninit(c);
+#else
+    printf("This test runs only on ARM\n");
+#endif
+}
+