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Optimize C version of ff_emulated_edge_mc().

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From ~780 cycles to 551 cycles, mostly just by using libc memcpy()
instead of manually shuffling individual bytes around.
This commit is contained in:
Ronald S. Bultje 2011-01-26 22:37:50 -05:00
parent 4d54df8e07
commit e5262ec44a
1 changed files with 23 additions and 16 deletions
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37
libavcodec/dsputil.c
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@ -355,38 +355,45 @@ void ff_emulated_edge_mc(uint8_t *buf, const uint8_t *src, int linesize, int blo
start_x= FFMAX(0, -src_x);
end_y= FFMIN(block_h, h-src_y);
end_x= FFMIN(block_w, w-src_x);
assert(start_y < end_y && block_h);
assert(start_x < end_x && block_w);
// copy existing part
for(y=start_y; y<end_y; y++){
for(x=start_x; x<end_x; x++){
buf[x + y*linesize]= src[x + y*linesize];
}
}
w = end_x - start_x;
src += start_y*linesize + start_x;
buf += start_x;
//top
for(y=0; y<start_y; y++){
for(x=start_x; x<end_x; x++){
buf[x + y*linesize]= buf[x + start_y*linesize];
memcpy(buf, src, w);
buf += linesize;
}
// copy existing part
for(; y<end_y; y++){
memcpy(buf, src, w);
src += linesize;
buf += linesize;
}
//bottom
for(y=end_y; y<block_h; y++){
for(x=start_x; x<end_x; x++){
buf[x + y*linesize]= buf[x + (end_y-1)*linesize];
}
src -= linesize;
for(; y<block_h; y++){
memcpy(buf, src, w);
buf += linesize;
}
for(y=0; y<block_h; y++){
buf -= block_h * linesize + start_x;
while (block_h--){
//left
for(x=0; x<start_x; x++){
buf[x + y*linesize]= buf[start_x + y*linesize];
buf[x] = buf[start_x];
}
//right
for(x=end_x; x<block_w; x++){
buf[x + y*linesize]= buf[end_x - 1 + y*linesize];
buf[x] = buf[end_x - 1];
}
buf += linesize;
}
}