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");