c2p_iplan2.c
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/*
* Fast C2P (Chunky-to-Planar) Conversion
*
* Copyright (C) 2003-2008 Geert Uytterhoeven
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive
* for more details.
*/
#include <linux/module.h>
#include <linux/string.h>
#include <asm/unaligned.h>
#include "c2p.h"
#include "c2p_core.h"
/*
* Perform a full C2P step on 16 8-bit pixels, stored in 4 32-bit words
* containing
* - 16 8-bit chunky pixels on input
* - permutated planar data (2 planes per 32-bit word) on output
*/
static void c2p_16x8(u32 d[4])
{
transp4(d, 8, 2);
transp4(d, 1, 2);
transp4x(d, 16, 2);
transp4x(d, 2, 2);
transp4(d, 4, 1);
}
/*
* Array containing the permutation indices of the planar data after c2p
*/
static const int perm_c2p_16x8[4] = { 1, 3, 0, 2 };
/*
* Store a full block of iplan2 data after c2p conversion
*/
static inline void store_iplan2(void *dst, u32 bpp, u32 d[4])
{
int i;
for (i = 0; i < bpp/2; i++, dst += 4)
put_unaligned_be32(d[perm_c2p_16x8[i]], dst);
}
/*
* Store a partial block of iplan2 data after c2p conversion
*/
static inline void store_iplan2_masked(void *dst, u32 bpp, u32 d[4], u32 mask)
{
int i;
for (i = 0; i < bpp/2; i++, dst += 4)
put_unaligned_be32(comp(d[perm_c2p_16x8[i]],
get_unaligned_be32(dst), mask),
dst);
}
/*
* c2p_iplan2 - Copy 8-bit chunky image data to an interleaved planar
* frame buffer with 2 bytes of interleave
* @dst: Starting address of the planar frame buffer
* @dx: Horizontal destination offset (in pixels)
* @dy: Vertical destination offset (in pixels)
* @width: Image width (in pixels)
* @height: Image height (in pixels)
* @dst_nextline: Frame buffer offset to the next line (in bytes)
* @src_nextline: Image offset to the next line (in bytes)
* @bpp: Bits per pixel of the planar frame buffer (2, 4, or 8)
*/
void c2p_iplan2(void *dst, const void *src, u32 dx, u32 dy, u32 width,
u32 height, u32 dst_nextline, u32 src_nextline, u32 bpp)
{
union {
u8 pixels[16];
u32 words[4];
} d;
u32 dst_idx, first, last, w;
const u8 *c;
void *p;
dst += dy*dst_nextline+(dx & ~15)*bpp;
dst_idx = dx % 16;
first = 0xffffU >> dst_idx;
first |= first << 16;
last = 0xffffU ^ (0xffffU >> ((dst_idx+width) % 16));
last |= last << 16;
while (height--) {
c = src;
p = dst;
w = width;
if (dst_idx+width <= 16) {
/* Single destination word */
first &= last;
memset(d.pixels, 0, sizeof(d));
memcpy(d.pixels+dst_idx, c, width);
c += width;
c2p_16x8(d.words);
store_iplan2_masked(p, bpp, d.words, first);
p += bpp*2;
} else {
/* Multiple destination words */
w = width;
/* Leading bits */
if (dst_idx) {
w = 16 - dst_idx;
memset(d.pixels, 0, dst_idx);
memcpy(d.pixels+dst_idx, c, w);
c += w;
c2p_16x8(d.words);
store_iplan2_masked(p, bpp, d.words, first);
p += bpp*2;
w = width-w;
}
/* Main chunk */
while (w >= 16) {
memcpy(d.pixels, c, 16);
c += 16;
c2p_16x8(d.words);
store_iplan2(p, bpp, d.words);
p += bpp*2;
w -= 16;
}
/* Trailing bits */
w %= 16;
if (w > 0) {
memcpy(d.pixels, c, w);
memset(d.pixels+w, 0, 16-w);
c2p_16x8(d.words);
store_iplan2_masked(p, bpp, d.words, last);
}
}
src += src_nextline;
dst += dst_nextline;
}
}
EXPORT_SYMBOL_GPL(c2p_iplan2);
MODULE_LICENSE("GPL");