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fbblit: Optimize by replacing division with additions and shifts.

This commit is contained in:
Vladimir Serbinenko 2015-02-26 18:14:28 +01:00
parent dd4889f727
commit f51218bc15
1 changed files with 41 additions and 30 deletions
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71
grub-core/video/fb/fbblit.c
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@ -1145,6 +1145,20 @@ grub_video_fbblit_replace_index_RGB888 (struct grub_video_fbblit_info *dst,
}
}
static inline grub_uint8_t
alpha_dilute (grub_uint8_t bg, grub_uint8_t fg, grub_uint8_t alpha)
{
grub_uint16_t s;
grub_uint16_t h, l;
s = (fg * alpha) + (bg * (255 ^ alpha));
/* Optimised division by 255. */
h = s >> 8;
l = s & 0xff;
if (h + l >= 255)
h++;
return h;
}
/* Generic blending blitter. Works for every supported format. */
static void
grub_video_fbblit_blend (struct grub_video_fbblit_info *dst,
@ -1190,12 +1204,9 @@ grub_video_fbblit_blend (struct grub_video_fbblit_info *dst,
grub_video_fb_unmap_color_int (dst, dst_color, &dst_red,
&dst_green, &dst_blue, &dst_alpha);
dst_red = (((src_red * src_alpha)
+ (dst_red * (255 ^ src_alpha))) / 255U);
dst_green = (((src_green * src_alpha)
+ (dst_green * (255 ^ src_alpha))) / 255U);
dst_blue = (((src_blue * src_alpha)
+ (dst_blue * (255 ^ src_alpha))) / 255U);
dst_red = alpha_dilute (dst_red, src_red, src_alpha);
dst_green = alpha_dilute (dst_green, src_green, src_alpha);
dst_blue = alpha_dilute (dst_blue, src_blue, src_alpha);
dst_alpha = src_alpha;
dst_color = grub_video_fb_map_rgba (dst_red, dst_green, dst_blue,
@ -1270,11 +1281,11 @@ grub_video_fbblit_blend_BGRA8888_RGBA8888 (struct grub_video_fbblit_info *dst,
color = *dstptr;
dr = (color >> 16) & 0xFF;
dr = (dr * (255 ^ a) + sr * a) / 255U;
dr = alpha_dilute (dr, sr, a);
dg = (color >> 8) & 0xFF;
dg = (dg * (255 ^ a) + sg * a) / 255U;
dg = alpha_dilute (dg, sg, a);
db = (color >> 0) & 0xFF;
db = (db * (255 ^ a) + sb * a) / 255U;
db = alpha_dilute (db, sb, a);
}
color = (a << 24) | (dr << 16) | (dg << 8) | db;
@ -1360,9 +1371,9 @@ grub_video_fbblit_blend_BGR888_RGBA8888 (struct grub_video_fbblit_info *dst,
db = dstptr[2];
#endif
db = (db * (255 ^ a) + sb * a) / 255U;
dg = (dg * (255 ^ a) + sg * a) / 255U;
dr = (dr * (255 ^ a) + sr * a) / 255U;
db = alpha_dilute (db, sb, a);
dg = alpha_dilute (dg, sg, a);
dr = alpha_dilute (dr, sr, a);
}
#ifndef GRUB_CPU_WORDS_BIGENDIAN
@ -1440,9 +1451,9 @@ grub_video_fbblit_blend_RGBA8888_RGBA8888 (struct grub_video_fbblit_info *dst,
dg = (color >> 8) & 0xFF;
db = (color >> 16) & 0xFF;
dr = (dr * (255 ^ a) + sr * a) / 255U;
dg = (dg * (255 ^ a) + sg * a) / 255U;
db = (db * (255 ^ a) + sb * a) / 255U;
dr = alpha_dilute (dr, sr, a);
dg = alpha_dilute (dg, sg, a);
db = alpha_dilute (db, sb, a);
color = (a << 24) | (db << 16) | (dg << 8) | dr;
@ -1525,9 +1536,9 @@ grub_video_fbblit_blend_RGB888_RGBA8888 (struct grub_video_fbblit_info *dst,
dr = dstptr[2];
#endif
dr = (dr * (255 ^ a) + sr * a) / 255U;
dg = (dg * (255 ^ a) + sg * a) / 255U;
db = (db * (255 ^ a) + sb * a) / 255U;
dr = alpha_dilute (dr, sr, a);
dg = alpha_dilute (dg, sg, a);
db = alpha_dilute (db, sb, a);
#ifndef GRUB_CPU_WORDS_BIGENDIAN
*dstptr++ = dr;
@ -1601,9 +1612,9 @@ grub_video_fbblit_blend_index_RGBA8888 (struct grub_video_fbblit_info *dst,
grub_video_fb_unmap_color_int (dst, *dstptr, &dr, &dg, &db, &da);
dr = (dr * (255 ^ a) + sr * a) / 255U;
dg = (dg * (255 ^ a) + sg * a) / 255U;
db = (db * (255 ^ a) + sb * a) / 255U;
dr = alpha_dilute (dr, sr, a);
dg = alpha_dilute (dg, sg, a);
db = alpha_dilute (db, sb, a);
color = grub_video_fb_map_rgb(dr, dg, db);
@ -1683,9 +1694,9 @@ grub_video_fbblit_blend_XXXA8888_1bit (struct grub_video_fbblit_info *dst,
grub_uint8_t d2 = (*dstptr >> 8) & 0xFF;
grub_uint8_t d3 = (*dstptr >> 16) & 0xFF;
d1 = (d1 * (255 ^ a) + s1 * a) / 255U;
d2 = (d2 * (255 ^ a) + s2 * a) / 255U;
d3 = (d3 * (255 ^ a) + s3 * a) / 255U;
d1 = alpha_dilute (d1, s1, a);
d2 = alpha_dilute (d2, s2, a);
d3 = alpha_dilute (d3, s3, a);
*dstptr = (a << 24) | (d3 << 16) | (d2 << 8) | d1;
}
@ -1791,9 +1802,9 @@ grub_video_fbblit_blend_XXX888_1bit (struct grub_video_fbblit_info *dst,
grub_uint8_t d2 = (*(grub_uint32_t *) dstptr >> 8) & 0xFF;
grub_uint8_t d3 = (*(grub_uint32_t *) dstptr >> 16) & 0xFF;
((grub_uint8_t *) dstptr)[0] = (d1 * (255 ^ a) + s1 * a) / 255U;
((grub_uint8_t *) dstptr)[1] = (d2 * (255 ^ a) + s2 * a) / 255U;
((grub_uint8_t *) dstptr)[2] = (d3 * (255 ^ a) + s3 * a) / 255U;
((grub_uint8_t *) dstptr)[0] = alpha_dilute (d1, s1, a);
((grub_uint8_t *) dstptr)[1] = alpha_dilute (d2, s2, a);
((grub_uint8_t *) dstptr)[2] = alpha_dilute (d3, s3, a);
}
srcmask >>= 1;
@ -1887,9 +1898,9 @@ grub_video_fbblit_blend_XXX565_1bit (struct grub_video_fbblit_info *dst,
grub_uint8_t d2 = (*dstptr >> 5) & 0x3F;
grub_uint8_t d3 = (*dstptr >> 11) & 0x1F;
d1 = (d1 * (255 ^ a) + s1 * a) / 255U;
d2 = (d2 * (255 ^ a) + s2 * a) / 255U;
d3 = (d3 * (255 ^ a) + s3 * a) / 255U;
d1 = alpha_dilute (d1, s1, a);
d2 = alpha_dilute (d2, s2, a);
d3 = alpha_dilute (d3, s3, a);
*dstptr = (d1 & 0x1f) | ((d2 & 0x3f) << 5) | ((d3 & 0x1f) << 11);
}