From f51218bc15ff7b82894a2096ec1cdb7c8f0084f4 Mon Sep 17 00:00:00 2001
From: Vladimir Serbinenko <phcoder@gmail.com>
Date: Thu, 26 Feb 2015 18:14:28 +0100
Subject: [PATCH 333/506] fbblit: Optimize by replacing division with additions
and shifts.
---
grub-core/video/fb/fbblit.c | 71 ++++++++++++++++++++++++++-------------------
1 file changed, 41 insertions(+), 30 deletions(-)
diff --git a/grub-core/video/fb/fbblit.c b/grub-core/video/fb/fbblit.c
index 3a073ce..d559248 100644
--- a/grub-core/video/fb/fbblit.c
+++ b/grub-core/video/fb/fbblit.c
@@ -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);
}
--
2.4.3