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lcd: Rewrite 16bit alpha bitmap blit

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Avoids a harmless out of bounds reads in ASAN that occurs with
malloc buflib. Code size and performance is similar.

Change-Id: I1c674d046b069e64ad8cb6941356f7c568a81e88
This commit is contained in:
Aidan MacDonald 2023-01-03 21:51:52 +00:00
parent b444ecfca2
commit 5d0c382a59
1 changed files with 220 additions and 225 deletions
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339
firmware/drivers/lcd-16bit-common.c
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@ -336,7 +336,7 @@ void lcd_mono_bitmap(const unsigned char *src, int x, int y, int width, int heig
}
/* About Rockbox' internal alpha channel format (for ALPHA_COLOR_FONT_DEPTH == 2)
/* About Rockbox' internal alpha channel format (for ALPHA_BPP == 4)
*
* For each pixel, 4bit of alpha information is stored in a byte-stream,
* so two pixels are packed into one byte.
@ -355,11 +355,15 @@ void lcd_mono_bitmap(const unsigned char *src, int x, int y, int width, int heig
* so lcd_bmp() do expect even rows.
*/
#define ALPHA_COLOR_FONT_DEPTH 2
#define ALPHA_COLOR_LOOKUP_SHIFT (1 << ALPHA_COLOR_FONT_DEPTH)
#define ALPHA_COLOR_LOOKUP_SIZE ((1 << ALPHA_COLOR_LOOKUP_SHIFT) - 1)
#define ALPHA_COLOR_PIXEL_PER_BYTE (8 >> ALPHA_COLOR_FONT_DEPTH)
#define ALPHA_COLOR_PIXEL_PER_WORD (32 >> ALPHA_COLOR_FONT_DEPTH)
#define ALPHA_BPP 4
#define ALPHA_MASK ((1 << ALPHA_BPP) - 1)
#define ALPHA_PIXELS_PER_BYTE (CHAR_BIT / ALPHA_BPP)
#define ALPHA_WORD_T uint32_t
#define ALPHA_WORD_LOAD load_le32
#define ALPHA_WORDSIZE sizeof(ALPHA_WORD_T)
#define ALPHA_PIXELS_PER_WORD (ALPHA_WORDSIZE * CHAR_BIT / ALPHA_BPP)
#ifdef CPU_ARM
#define BLEND_INIT do {} while (0)
#define BLEND_FINISH do {} while(0)
@ -368,6 +372,7 @@ void lcd_mono_bitmap(const unsigned char *src, int x, int y, int width, int heig
#define BLEND_CONT(acc, color, alpha) \
asm volatile("mla %0, %1, %2, %0" : "+&r" (acc) : "r" (color), "r" (alpha))
#define BLEND_OUT(acc) do {} while (0)
#elif defined(CPU_COLDFIRE)
#define ALPHA_BITMAP_READ_WORDS
#define BLEND_INIT \
@ -379,6 +384,7 @@ void lcd_mono_bitmap(const unsigned char *src, int x, int y, int width, int heig
asm volatile("mac.l %0, %1, %%acc0" :: "%d" (color), "d" (alpha))
#define BLEND_CONT BLEND_START
#define BLEND_OUT(acc) asm volatile("movclr.l %%acc0, %0" : "=d" (acc))
#else
#define BLEND_INIT do {} while (0)
#define BLEND_FINISH do {} while(0)
@ -390,7 +396,7 @@ void lcd_mono_bitmap(const unsigned char *src, int x, int y, int width, int heig
/* Blend the given two colors */
static inline unsigned blend_two_colors(unsigned c1, unsigned c2, unsigned a)
{
a += a >> (ALPHA_COLOR_LOOKUP_SHIFT - 1);
a += a >> (ALPHA_BPP - 1);
#if (LCD_PIXELFORMAT == RGB565SWAPPED)
c1 = swap16(c1);
c2 = swap16(c2);
@ -399,9 +405,9 @@ static inline unsigned blend_two_colors(unsigned c1, unsigned c2, unsigned a)
unsigned c2l = (c2 | (c2 << 16)) & 0x07e0f81f;
unsigned p;
BLEND_START(p, c1l, a);
BLEND_CONT(p, c2l, ALPHA_COLOR_LOOKUP_SIZE + 1 - a);
BLEND_CONT(p, c2l, ALPHA_MASK + 1 - a);
BLEND_OUT(p);
p = (p >> ALPHA_COLOR_LOOKUP_SHIFT) & 0x07e0f81f;
p = (p >> ALPHA_BPP) & 0x07e0f81f;
p |= (p >> 16);
#if (LCD_PIXELFORMAT == RGB565SWAPPED)
return swap16(p);
@ -410,251 +416,240 @@ static inline unsigned blend_two_colors(unsigned c1, unsigned c2, unsigned a)
#endif
}
/* Blend an image with an alpha channel
* if image is NULL, drawing will happen according to the drawmode
* src is the alpha channel (4bit per pixel) */
static void ICODE_ATTR lcd_alpha_bitmap_part_mix(const fb_data* image,
const unsigned char *src, int src_x,
int src_y, int x, int y,
int width, int height,
int stride_image, int stride_src)
static void ICODE_ATTR lcd_alpha_bitmap_part_mix(
const fb_data* image, const unsigned char *alpha,
int src_x, int src_y,
int x, int y, int width, int height,
int stride_image, int stride_alpha)
{
struct viewport *vp = lcd_current_viewport;
fb_data *dst, *dst_row;
unsigned dmask = 0x00000000;
unsigned int dmask = 0;
int drmode = vp->drawmode;
fb_data *dst;
#ifdef ALPHA_BITMAP_READ_WORDS
ALPHA_WORD_T alpha_data, *alpha_word;
size_t alpha_offset = 0, alpha_pixels;
#else
unsigned char alpha_data;
size_t alpha_pixels;
#endif
if (!clip_viewport_rect(vp, &x, &y, &width, &height, &src_x, &src_y))
return;
/* initialize blending */
BLEND_INIT;
/* the following drawmode combinations are possible:
* 1) COMPLEMENT: just negates the framebuffer contents
* 2) BG and BG+backdrop: draws _only_ background pixels with either
* the background color or the backdrop (if any). The backdrop
* is an image in native lcd format
* 3) FG and FG+image: draws _only_ foreground pixels with either
* the foreground color or an image buffer. The image is in
* native lcd format
* 4) SOLID, SOLID+backdrop, SOLID+image, SOLID+backdrop+image, i.e. all
* possible combinations of 2) and 3). Draws both, fore- and background,
* pixels. The rules of 2) and 3) apply.
*
* INVERSEVID swaps fore- and background pixels, i.e. background pixels
* become foreground ones and vice versa.
*/
if (drmode & DRMODE_INVERSEVID)
{
dmask = 0xffffffff;
drmode &= DRMODE_SOLID; /* mask out inversevid */
dmask = 0xFFFFFFFFu;
drmode &= ~DRMODE_INVERSEVID;
}
/* Use extra bits to avoid if () in the switch-cases below */
if (image != NULL)
drmode |= DRMODE_INT_IMG;
if ((drmode & DRMODE_BG) && lcd_backdrop)
drmode |= DRMODE_INT_BD;
dst_row = FBADDR(x, y);
int col, row = height;
unsigned data, pixels;
unsigned skip_end = (stride_src - width);
unsigned skip_start = src_y * stride_src + src_x;
unsigned skip_start_image = STRIDE_MAIN(src_y * stride_image + src_x,
src_x * stride_image + src_y);
#ifdef ALPHA_BITMAP_READ_WORDS
uint32_t *src_w = (uint32_t *)((uintptr_t)src & ~3);
skip_start += ALPHA_COLOR_PIXEL_PER_BYTE * ((uintptr_t)src & 3);
src_w += skip_start / ALPHA_COLOR_PIXEL_PER_WORD;
data = letoh32(*src_w++) ^ dmask;
pixels = skip_start % ALPHA_COLOR_PIXEL_PER_WORD;
#else
src += skip_start / ALPHA_COLOR_PIXEL_PER_BYTE;
data = *src ^ dmask;
pixels = skip_start % ALPHA_COLOR_PIXEL_PER_BYTE;
#endif
data >>= pixels * ALPHA_COLOR_LOOKUP_SHIFT;
#ifdef ALPHA_BITMAP_READ_WORDS
pixels = 8 - pixels;
#endif
/* image is only accessed in DRMODE_INT_IMG cases, i.e. when non-NULL.
* Therefore NULL accesses are impossible and we can increment
* unconditionally (applies for stride at the end of the loop as well) */
image += skip_start_image;
/* go through the rows and update each pixel */
do
{
/* saving lcd_current_viewport->fg/bg_pattern and lcd_backdrop_offset into these
* temp vars just before the loop helps gcc to opimize the loop better
* (testing showed ~15% speedup) */
unsigned fg, bg;
ptrdiff_t bo, img_offset;
col = width;
dst = dst_row;
dst_row += ROW_INC;
#ifdef ALPHA_BITMAP_READ_WORDS
#define UPDATE_SRC_ALPHA do { \
if (--pixels) \
data >>= ALPHA_COLOR_LOOKUP_SHIFT; \
else \
{ \
data = letoh32(*src_w++) ^ dmask; \
pixels = ALPHA_COLOR_PIXEL_PER_WORD; \
#define INIT_ALPHA() \
do { \
alpha_offset = src_y * stride_alpha + src_x; \
} while(0)
#define START_ALPHA() \
do { \
size_t __byteskip = (uintptr_t)alpha % ALPHA_WORDSIZE; \
size_t __byteoff = alpha_offset / ALPHA_PIXELS_PER_BYTE; \
alpha_word = (ALPHA_WORD_T *)ALIGN_DOWN(alpha + __byteoff, ALPHA_WORDSIZE); \
alpha_data = ALPHA_WORD_LOAD(alpha_word++) ^ dmask; \
alpha_pixels = ((__byteoff + __byteskip) % ALPHA_WORDSIZE) * ALPHA_PIXELS_PER_BYTE; \
alpha_pixels += alpha_offset % ALPHA_PIXELS_PER_BYTE; \
alpha_data >>= alpha_pixels * ALPHA_BPP; \
alpha_pixels = ALPHA_PIXELS_PER_WORD - alpha_pixels; \
} while(0)
#define END_ALPHA() \
do { \
alpha_offset += stride_alpha; \
} while(0)
#define READ_ALPHA() \
({ \
if (alpha_pixels == 0) { \
alpha_data = ALPHA_WORD_LOAD(alpha_word++) ^ dmask; \
alpha_pixels = ALPHA_PIXELS_PER_WORD; \
} \
ALPHA_WORD_T __ret = alpha_data & ALPHA_MASK; \
alpha_data >>= ALPHA_BPP; \
alpha_pixels--; \
__ret; \
})
#elif ALPHA_BPP == 4
#define INIT_ALPHA() \
do { \
alpha_pixels = src_y * stride_alpha + src_x; \
stride_alpha = stride_alpha - width; \
alpha += alpha_pixels / ALPHA_PIXELS_PER_BYTE; \
alpha_pixels &= 1; \
if (alpha_pixels) { \
alpha_data = *alpha++ ^ dmask; \
alpha_data >>= ALPHA_BPP; \
} \
} while(0)
#elif ALPHA_COLOR_PIXEL_PER_BYTE == 2
#define UPDATE_SRC_ALPHA do { \
if (pixels ^= 1) \
data >>= ALPHA_COLOR_LOOKUP_SHIFT; \
else \
data = *(++src) ^ dmask; \
#define START_ALPHA() do { } while(0)
#define END_ALPHA() \
do { \
if (stride_alpha) { \
alpha_pixels = stride_alpha - alpha_pixels; \
alpha += alpha_pixels / ALPHA_PIXELS_PER_BYTE; \
alpha_data = *alpha++ ^ dmask; \
alpha_pixels &= 1; \
if (alpha_pixels) \
alpha_data >>= ALPHA_BPP; \
} \
} while(0)
#define READ_ALPHA() \
({ \
if (alpha_pixels == 0) \
alpha_data = *alpha++ ^ dmask; \
unsigned char __ret = alpha_data & ALPHA_MASK; \
alpha_data >>= ALPHA_BPP; \
alpha_pixels ^= 1; \
__ret; \
})
#else
#define UPDATE_SRC_ALPHA do { \
if (pixels = (++pixels % ALPHA_COLOR_PIXEL_PER_BYTE)) \
data >>= ALPHA_COLOR_LOOKUP_SHIFT; \
else \
data = *(++src) ^ dmask; \
#define INIT_ALPHA() \
do { \
alpha_pixels = src_y * stride_alpha + src_x; \
stride_alpha = stride_alpha - width; \
alpha += alpha_pixels / ALPHA_PIXELS_PER_BYTE; \
alpha_data = *alpha++ ^ dmask; \
alpha_pixels %= ALPHA_PIXELS_PER_BYTE; \
alpha_data >>= ALPHA_BPP * alpha_pixels; \
alpha_pixels = ALPHA_PIXELS_PER_BYTE - alpha_pixels; \
} while(0)
#define START_ALPHA() do { } while(0)
#define END_ALPHA() \
do { \
if ((size_t)stride_alpha <= alpha_pixels) \
alpha_pixels -= stride_alpha; \
else { \
alpha_pixels = stride_alpha - alpha_pixels; \
alpha += alpha_pixels / ALPHA_PIXELS_PER_BYTE; \
alpha_data = *alpha++ ^ dmask; \
alpha_pixels %= ALPHA_PIXELS_PER_BYTE; \
alpha_data >>= ALPHA_BPP * alpha_pixels; \
alpha_pixels = ALPHA_PIXELS_PER_BYTE - alpha_pixels; \
} \
} while(0)
#define READ_ALPHA() \
({ \
if (alpha_pixels == 0) { \
alpha_data = *alpha++ ^ dmask; \
alpha_pixels = ALPHA_PIXELS_PER_BYTE; \
} \
unsigned char __ret = alpha_data & ALPHA_MASK; \
alpha_data >>= ALPHA_BPP; \
alpha_pixels--; \
__ret; \
})
#endif
dst = FBADDR(x, y);
image += STRIDE_MAIN(src_y * stride_image + src_x,
src_x * stride_image + src_y);
INIT_ALPHA();
BLEND_INIT;
do
{
intptr_t bo, io;
unsigned int fg, bg;
int col = width;
fb_data *dst_row = dst;
START_ALPHA();
switch (drmode)
{
case DRMODE_COMPLEMENT:
do
{
*dst = blend_two_colors(*dst, ~(*dst),
data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(*dst, ~(*dst), READ_ALPHA());
dst += COL_INC;
UPDATE_SRC_ALPHA;
}
while (--col);
} while (--col);
break;
case DRMODE_BG|DRMODE_INT_BD:
bo = lcd_backdrop_offset;
do
{
fb_data c = *(fb_data *)((uintptr_t)dst + bo);
*dst = blend_two_colors(c, *dst, data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(*PTR_ADD(dst, bo), *dst, READ_ALPHA());
dst += COL_INC;
image += STRIDE_MAIN(1, stride_image);
UPDATE_SRC_ALPHA;
}
while (--col);
} while (--col);
break;
case DRMODE_BG:
bg = vp->bg_pattern;
do
{
*dst = blend_two_colors(bg, *dst, data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(bg, *dst, READ_ALPHA());
dst += COL_INC;
UPDATE_SRC_ALPHA;
}
while (--col);
} while (--col);
break;
case DRMODE_FG|DRMODE_INT_IMG:
img_offset = image - dst;
io = image - dst;
do
{
*dst = blend_two_colors(*dst, *(dst + img_offset), data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(*dst, *(dst + io), READ_ALPHA());
dst += COL_INC;
UPDATE_SRC_ALPHA;
}
while (--col);
} while (--col);
break;
case DRMODE_FG:
fg = vp->fg_pattern;
do
{
*dst = blend_two_colors(*dst, fg, data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(*dst, fg, READ_ALPHA());
dst += COL_INC;
UPDATE_SRC_ALPHA;
}
while (--col);
} while (--col);
break;
case DRMODE_SOLID|DRMODE_INT_BD:
bo = lcd_backdrop_offset;
fg = vp->fg_pattern;
bo = lcd_backdrop_offset;
do
{
fb_data *c = (fb_data *)((uintptr_t)dst + bo);
*dst = blend_two_colors(*c, fg, data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(*PTR_ADD(dst, bo), fg, READ_ALPHA());
dst += COL_INC;
UPDATE_SRC_ALPHA;
}
while (--col);
} while (--col);
break;
case DRMODE_SOLID|DRMODE_INT_IMG:
bg = vp->bg_pattern;
img_offset = image - dst;
io = image - dst;
do
{
*dst = blend_two_colors(bg, *(dst + img_offset), data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(bg, *(dst + io), READ_ALPHA());
dst += COL_INC;
UPDATE_SRC_ALPHA;
}
while (--col);
} while (--col);
break;
case DRMODE_SOLID|DRMODE_INT_BD|DRMODE_INT_IMG:
bo = lcd_backdrop_offset;
img_offset = image - dst;
io = image - dst;
do
{
fb_data *c = (fb_data *)((uintptr_t)dst + bo);
*dst = blend_two_colors(*c, *(dst + img_offset), data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(*PTR_ADD(dst, bo), *(dst + io), READ_ALPHA());
dst += COL_INC;
UPDATE_SRC_ALPHA;
}
while (--col);
} while (--col);
break;
case DRMODE_SOLID:
bg = vp->bg_pattern;
fg = vp->fg_pattern;
bg = vp->bg_pattern;
do
{
*dst = blend_two_colors(bg, fg, data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(bg, fg, READ_ALPHA());
dst += COL_INC;
UPDATE_SRC_ALPHA;
}
while (--col);
} while (--col);
break;
}
#ifdef ALPHA_BITMAP_READ_WORDS
if (skip_end < pixels)
{
pixels -= skip_end;
data >>= skip_end * ALPHA_COLOR_LOOKUP_SHIFT;
} else {
pixels = skip_end - pixels;
src_w += pixels / ALPHA_COLOR_PIXEL_PER_WORD;
pixels %= ALPHA_COLOR_PIXEL_PER_WORD;
data = letoh32(*src_w++) ^ dmask;
data >>= pixels * ALPHA_COLOR_LOOKUP_SHIFT;
pixels = 8 - pixels;
}
#else
if (skip_end)
{
pixels += skip_end;
if (pixels >= ALPHA_COLOR_PIXEL_PER_BYTE)
{
src += pixels / ALPHA_COLOR_PIXEL_PER_BYTE;
pixels %= ALPHA_COLOR_PIXEL_PER_BYTE;
data = *src ^ dmask;
data >>= pixels * ALPHA_COLOR_LOOKUP_SHIFT;
} else
data >>= skip_end * ALPHA_COLOR_LOOKUP_SHIFT;
}
#endif
END_ALPHA();
image += STRIDE_MAIN(stride_image, 1);
} while (--row);
dst = dst_row + ROW_INC;
} while (--height);
BLEND_FINISH;
}