c2p_planar.c

  1/*
  2 *  Fast C2P (Chunky-to-Planar) Conversion
  3 *
  4 *  Copyright (C) 2003-2008 Geert Uytterhoeven
  5 *
  6 *  This file is subject to the terms and conditions of the GNU General Public
  7 *  License. See the file COPYING in the main directory of this archive
  8 *  for more details.
  9 */
 10
 11#include <linux/export.h>
 12#include <linux/module.h>
 13#include <linux/string.h>
 14
 15#include <linux/unaligned.h>
 16
 17#include "c2p.h"
 18#include "c2p_core.h"
 19
 20
 21    /*
 22     *  Perform a full C2P step on 32 8-bit pixels, stored in 8 32-bit words
 23     *  containing
 24     *    - 32 8-bit chunky pixels on input
 25     *    - permutated planar data (1 plane per 32-bit word) on output
 26     */
 27
 28static void c2p_32x8(u32 d[8])
 29{
 30	transp8(d, 16, 4);
 31	transp8(d, 8, 2);
 32	transp8(d, 4, 1);
 33	transp8(d, 2, 4);
 34	transp8(d, 1, 2);
 35}
 36
 37
 38    /*
 39     *  Array containing the permutation indices of the planar data after c2p
 40     */
 41
 42static const int perm_c2p_32x8[8] = { 7, 5, 3, 1, 6, 4, 2, 0 };
 43
 44
 45    /*
 46     *  Store a full block of planar data after c2p conversion
 47     */
 48
 49static inline void store_planar(void *dst, u32 dst_inc, u32 bpp, u32 d[8])
 50{
 51	int i;
 52
 53	for (i = 0; i < bpp; i++, dst += dst_inc)
 54		put_unaligned_be32(d[perm_c2p_32x8[i]], dst);
 55}
 56
 57
 58    /*
 59     *  Store a partial block of planar data after c2p conversion
 60     */
 61
 62static inline void store_planar_masked(void *dst, u32 dst_inc, u32 bpp,
 63				       u32 d[8], u32 mask)
 64{
 65	int i;
 66
 67	for (i = 0; i < bpp; i++, dst += dst_inc)
 68		put_unaligned_be32(comp(d[perm_c2p_32x8[i]],
 69					get_unaligned_be32(dst), mask),
 70				   dst);
 71}
 72
 73
 74    /*
 75     *  c2p_planar - Copy 8-bit chunky image data to a planar frame buffer
 76     *  @dst: Starting address of the planar frame buffer
 77     *  @dx: Horizontal destination offset (in pixels)
 78     *  @dy: Vertical destination offset (in pixels)
 79     *  @width: Image width (in pixels)
 80     *  @height: Image height (in pixels)
 81     *  @dst_nextline: Frame buffer offset to the next line (in bytes)
 82     *  @dst_nextplane: Frame buffer offset to the next plane (in bytes)
 83     *  @src_nextline: Image offset to the next line (in bytes)
 84     *  @bpp: Bits per pixel of the planar frame buffer (1-8)
 85     */
 86
 87void c2p_planar(void *dst, const void *src, u32 dx, u32 dy, u32 width,
 88		u32 height, u32 dst_nextline, u32 dst_nextplane,
 89		u32 src_nextline, u32 bpp)
 90{
 91	union {
 92		u8 pixels[32];
 93		u32 words[8];
 94	} d;
 95	u32 dst_idx, first, last, w;
 96	const u8 *c;
 97	void *p;
 98
 99	dst += dy*dst_nextline+(dx & ~31);
100	dst_idx = dx % 32;
101	first = 0xffffffffU >> dst_idx;
102	last = ~(0xffffffffU >> ((dst_idx+width) % 32));
103	while (height--) {
104		c = src;
105		p = dst;
106		w = width;
107		if (dst_idx+width <= 32) {
108			/* Single destination word */
109			first &= last;
110			memset(d.pixels, 0, sizeof(d));
111			memcpy(d.pixels+dst_idx, c, width);
112			c += width;
113			c2p_32x8(d.words);
114			store_planar_masked(p, dst_nextplane, bpp, d.words,
115					    first);
116			p += 4;
117		} else {
118			/* Multiple destination words */
119			w = width;
120			/* Leading bits */
121			if (dst_idx) {
122				w = 32 - dst_idx;
123				memset(d.pixels, 0, dst_idx);
124				memcpy(d.pixels+dst_idx, c, w);
125				c += w;
126				c2p_32x8(d.words);
127				store_planar_masked(p, dst_nextplane, bpp,
128						    d.words, first);
129				p += 4;
130				w = width-w;
131			}
132			/* Main chunk */
133			while (w >= 32) {
134				memcpy(d.pixels, c, 32);
135				c += 32;
136				c2p_32x8(d.words);
137				store_planar(p, dst_nextplane, bpp, d.words);
138				p += 4;
139				w -= 32;
140			}
141			/* Trailing bits */
142			w %= 32;
143			if (w > 0) {
144				memcpy(d.pixels, c, w);
145				memset(d.pixels+w, 0, 32-w);
146				c2p_32x8(d.words);
147				store_planar_masked(p, dst_nextplane, bpp,
148						    d.words, last);
149			}
150		}
151		src += src_nextline;
152		dst += dst_nextline;
153	}
154}
155EXPORT_SYMBOL_GPL(c2p_planar);
156
157MODULE_DESCRIPTION("Fast C2P (Chunky-to-Planar) Conversion");
158MODULE_LICENSE("GPL");