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bitmap drawing: use temp vars to help gcc opmize loops.

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By saving current_vp fields into temp vars just before the loop gcc can
put them into registers. This yields ~15% speedup for drawing anti-aliased fonts.

Change-Id: I4c0c9f5ff7a7f084e2eb08c4ed874176b1f9832c
This commit is contained in:
Thomas Martitz 2013-02-08 23:41:51 +01:00
parent 1430b07894
commit 68d3ce2acd
1 changed files with 10 additions and 10 deletions
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20
firmware/drivers/lcd-16bit-common.c
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@ -853,12 +853,6 @@ static inline unsigned blend_two_colors(unsigned c1, unsigned c2, unsigned a)
#endif
}
/* Blend the given color with the value from the alpha_color_lookup table */
static inline unsigned blend_color(unsigned c, unsigned a)
{
return blend_two_colors(c, current_vp->fg_pattern, a);
}
/* 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) */
@ -979,7 +973,10 @@ static void ICODE_ATTR lcd_alpha_bitmap_part_mix(const fb_data* image,
/* go through the rows and update each pixel */
do
{
unsigned bg;
/* saving current_vp->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;
uintptr_t bo;
col = width;
dst = dst_row;
@ -1053,9 +1050,10 @@ static void ICODE_ATTR lcd_alpha_bitmap_part_mix(const fb_data* image,
while (--col);
break;
case DRMODE_FG:
fg = current_vp->fg_pattern;
do
{
*dst = blend_color(*dst, data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(*dst, fg, data & ALPHA_COLOR_LOOKUP_SIZE );
dst += COL_INC;
UPDATE_SRC_ALPHA;
}
@ -1063,10 +1061,11 @@ static void ICODE_ATTR lcd_alpha_bitmap_part_mix(const fb_data* image,
break;
case DRMODE_SOLID|DRMODE_INT_MOD:
bo = lcd_backdrop_offset;
fg = current_vp->fg_pattern;
do
{
fb_data *c = (fb_data *)((uintptr_t)dst + bo);
*dst = blend_color(*c, data & ALPHA_COLOR_LOOKUP_SIZE );
*dst = blend_two_colors(*c, fg, data & ALPHA_COLOR_LOOKUP_SIZE );
dst += COL_INC;
UPDATE_SRC_ALPHA;
}
@ -1074,9 +1073,10 @@ static void ICODE_ATTR lcd_alpha_bitmap_part_mix(const fb_data* image,
break;
case DRMODE_SOLID:
bg = current_vp->bg_pattern;
fg = current_vp->fg_pattern;
do
{
*dst = blend_color(bg,
*dst = blend_two_colors(bg, fg,
data & ALPHA_COLOR_LOOKUP_SIZE );
dst += COL_INC;
UPDATE_SRC_ALPHA;