157 строки
3.6 KiB
C
157 строки
3.6 KiB
C
/*
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* Fast C2P (Chunky-to-Planar) Conversion
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*
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* Copyright (C) 2003-2008 Geert Uytterhoeven
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file COPYING in the main directory of this archive
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* for more details.
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*/
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#include <linux/module.h>
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#include <linux/string.h>
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#include <asm/unaligned.h>
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#include "c2p.h"
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#include "c2p_core.h"
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/*
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* Perform a full C2P step on 32 8-bit pixels, stored in 8 32-bit words
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* containing
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* - 32 8-bit chunky pixels on input
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* - permutated planar data (1 plane per 32-bit word) on output
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*/
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static void c2p_32x8(u32 d[8])
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{
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transp8(d, 16, 4);
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transp8(d, 8, 2);
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transp8(d, 4, 1);
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transp8(d, 2, 4);
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transp8(d, 1, 2);
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}
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/*
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* Array containing the permutation indices of the planar data after c2p
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*/
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static const int perm_c2p_32x8[8] = { 7, 5, 3, 1, 6, 4, 2, 0 };
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/*
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* Store a full block of planar data after c2p conversion
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*/
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static inline void store_planar(void *dst, u32 dst_inc, u32 bpp, u32 d[8])
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{
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int i;
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for (i = 0; i < bpp; i++, dst += dst_inc)
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put_unaligned_be32(d[perm_c2p_32x8[i]], dst);
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}
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/*
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* Store a partial block of planar data after c2p conversion
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*/
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static inline void store_planar_masked(void *dst, u32 dst_inc, u32 bpp,
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u32 d[8], u32 mask)
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{
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int i;
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for (i = 0; i < bpp; i++, dst += dst_inc)
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put_unaligned_be32(comp(d[perm_c2p_32x8[i]],
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get_unaligned_be32(dst), mask),
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dst);
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}
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/*
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* c2p_planar - Copy 8-bit chunky image data to a planar frame buffer
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* @dst: Starting address of the planar frame buffer
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* @dx: Horizontal destination offset (in pixels)
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* @dy: Vertical destination offset (in pixels)
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* @width: Image width (in pixels)
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* @height: Image height (in pixels)
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* @dst_nextline: Frame buffer offset to the next line (in bytes)
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* @dst_nextplane: Frame buffer offset to the next plane (in bytes)
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* @src_nextline: Image offset to the next line (in bytes)
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* @bpp: Bits per pixel of the planar frame buffer (1-8)
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*/
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void c2p_planar(void *dst, const void *src, u32 dx, u32 dy, u32 width,
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u32 height, u32 dst_nextline, u32 dst_nextplane,
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u32 src_nextline, u32 bpp)
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{
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union {
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u8 pixels[32];
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u32 words[8];
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} d;
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u32 dst_idx, first, last, w;
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const u8 *c;
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void *p;
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dst += dy*dst_nextline+(dx & ~31);
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dst_idx = dx % 32;
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first = 0xffffffffU >> dst_idx;
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last = ~(0xffffffffU >> ((dst_idx+width) % 32));
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while (height--) {
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c = src;
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p = dst;
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w = width;
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if (dst_idx+width <= 32) {
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/* Single destination word */
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first &= last;
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memset(d.pixels, 0, sizeof(d));
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memcpy(d.pixels+dst_idx, c, width);
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c += width;
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c2p_32x8(d.words);
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store_planar_masked(p, dst_nextplane, bpp, d.words,
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first);
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p += 4;
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} else {
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/* Multiple destination words */
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w = width;
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/* Leading bits */
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if (dst_idx) {
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w = 32 - dst_idx;
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memset(d.pixels, 0, dst_idx);
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memcpy(d.pixels+dst_idx, c, w);
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c += w;
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c2p_32x8(d.words);
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store_planar_masked(p, dst_nextplane, bpp,
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d.words, first);
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p += 4;
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w = width-w;
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}
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/* Main chunk */
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while (w >= 32) {
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memcpy(d.pixels, c, 32);
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c += 32;
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c2p_32x8(d.words);
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store_planar(p, dst_nextplane, bpp, d.words);
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p += 4;
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w -= 32;
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}
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/* Trailing bits */
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w %= 32;
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if (w > 0) {
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memcpy(d.pixels, c, w);
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memset(d.pixels+w, 0, 32-w);
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c2p_32x8(d.words);
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store_planar_masked(p, dst_nextplane, bpp,
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d.words, last);
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}
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}
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src += src_nextline;
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dst += dst_nextline;
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}
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}
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EXPORT_SYMBOL_GPL(c2p_planar);
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MODULE_LICENSE("GPL");
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