154 строки
3.5 KiB
C
154 строки
3.5 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 16 8-bit pixels, stored in 4 32-bit words
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* containing
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* - 16 8-bit chunky pixels on input
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* - permutated planar data (2 planes per 32-bit word) on output
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*/
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static void c2p_16x8(u32 d[4])
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{
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transp4(d, 8, 2);
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transp4(d, 1, 2);
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transp4x(d, 16, 2);
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transp4x(d, 2, 2);
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transp4(d, 4, 1);
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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_16x8[4] = { 1, 3, 0, 2 };
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/*
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* Store a full block of iplan2 data after c2p conversion
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*/
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static inline void store_iplan2(void *dst, u32 bpp, u32 d[4])
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{
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int i;
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for (i = 0; i < bpp/2; i++, dst += 4)
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put_unaligned_be32(d[perm_c2p_16x8[i]], dst);
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}
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/*
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* Store a partial block of iplan2 data after c2p conversion
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*/
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static inline void store_iplan2_masked(void *dst, u32 bpp, u32 d[4], u32 mask)
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{
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int i;
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for (i = 0; i < bpp/2; i++, dst += 4)
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put_unaligned_be32(comp(d[perm_c2p_16x8[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_iplan2 - Copy 8-bit chunky image data to an interleaved planar
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* frame buffer with 2 bytes of interleave
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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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* @src_nextline: Image offset to the next line (in bytes)
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* @bpp: Bits per pixel of the planar frame buffer (2, 4, or 8)
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*/
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void c2p_iplan2(void *dst, const void *src, u32 dx, u32 dy, u32 width,
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u32 height, u32 dst_nextline, u32 src_nextline, u32 bpp)
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{
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union {
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u8 pixels[16];
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u32 words[4];
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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 & ~15)*bpp;
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dst_idx = dx % 16;
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first = 0xffffU >> dst_idx;
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first |= first << 16;
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last = 0xffffU ^ (0xffffU >> ((dst_idx+width) % 16));
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last |= last << 16;
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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 <= 16) {
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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_16x8(d.words);
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store_iplan2_masked(p, bpp, d.words, first);
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p += bpp*2;
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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 = 16 - 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_16x8(d.words);
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store_iplan2_masked(p, bpp, d.words, first);
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p += bpp*2;
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w = width-w;
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}
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/* Main chunk */
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while (w >= 16) {
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memcpy(d.pixels, c, 16);
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c += 16;
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c2p_16x8(d.words);
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store_iplan2(p, bpp, d.words);
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p += bpp*2;
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w -= 16;
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}
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/* Trailing bits */
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w %= 16;
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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, 16-w);
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c2p_16x8(d.words);
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store_iplan2_masked(p, bpp, 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_iplan2);
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MODULE_LICENSE("GPL");
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